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  • 1.
    Bérard, Adrien
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Isikveren, Askin
    Dept. of Aerospace Engineering, University of Bristol.
    CADac: A New Geometry Construction Tool for Aerospace Vehicle Pre-Design and Conceptual Design2008In: 26th AIAA Applied Aerodynamics Conference: Honolulu, HI: 18 August 2008 through 21 August 2008, 2008Conference paper (Refereed)
    Abstract [en]

    In view of a continuous increase of computer performance, it is nowadays feasable to use CFD (Computational Fluid Dynamics) analysis very early in the conceptual design stage, if not the pre-concept phase, of aircraft. This requires the generation of a CAD (Computer Aided Design) model suitable for CFD computations, which is a tedious and time consuming process because a disconnect exists between the geometrical definition required for a CAD model and the limited number of geometry related design parameters defined by the designer. An additional complication to this is the requirement of producing a closed and consistent CAD model suitable for problem setup of CFD computations. The CADac (CAD-aircraft) tool nils this gap by automating the generation of closed and consistent CAD models via the implementation of a parameterized approach to conceptual design. CADac enables therefore to use CFD earlier and to use tools with inter-laced fidelity at the conceptual design phase.

  • 2.
    Bérard, Adrien
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Isikveren, Askin
    Development and Implementation of Aerodynamic Analysis Methods for Aircraft Conceptual Design2007Conference paper (Other academic)
  • 3. Böhnke, D.
    et al.
    Nagel, B.
    Zhang, Mengmeng
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Towards a collaborative and integrated set of open tools for aircraft design2013In: 51st AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition 2013, Deutsches Zentrum fuer Luftund Raumfahrt e.V. (DLR) , 2013Conference paper (Refereed)
    Abstract [en]

    A third generation Multi-Disciplinary Analysis & Optimization setup includes the collaboration of a distributed team of disciplinary experts and their respective anylsis tool to perform aircraft design. The integration of these tools can be eased by the application of open source software leaving more resources for the actual design task. Within the scope of this paper three open tools for aircraft design (OpenVSP, CEASIOM and VAMPzero) are introduced and integrated via a common namespace (CPACS). A design study on a two-engine transport aircraft is set up as an exemplary workflow.

  • 4.
    Cavagna, L.
    et al.
    Dipartimento di Ingegneria Aerospaziale, Politecnico di Milano.
    Riccobene, L.
    Dipartimento di Ingegneria Aerospaziale, Politecnico di Milano.
    Ricci, S.
    Dipartimento di Ingegneria Aerospaziale, Politecnico di Milano.
    Bérard, Adrien
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    A Fast MDO tool for Aeroelastic Optimization in Aircraft Conceptual Design2008Conference paper (Other academic)
    Abstract [en]

    This paper presents a design tool based on computational methods for the aero-structural analysis and optimization of aircraft layouts at the conceptual design stage. The whole methodology is based upon the integration of geometry construction, aerodynamic and structural analysis codes that combine depictive, computational, analytical, and semiempirical methods, validated in an aircraft design environment. The two primary modules are presented: CADac (Computer Aided Design Aircraft) for parametric geometry handling and NeoCASS (Next generation Conceptual Aero-Structural Sizing Suite) for structural sizing and numerical aeroelastic analysis. The aero-structural numerical kernel enables the creation of efficient low-order, high fidelity models which makes particularly suitable to be succesfully used within an MDO framework to drive the optimization tool into the most appropriate direction. Indeed, solving adverse aeroelastic issues like divergence, control surfaces reversal, flutter, increased drag at cruise speed due to structural deformability may require considerable changes in the structural design, limitations in flight envelope or weight penalties. The late discovery of this type of issues may result in significant cost increases and, in some cases, it may even require to actually close the project. In order to overcome the insurgence of these issues, the influence of deformability on flight and handling performances, on structural weight and on design costs needs to be taken into account as early as possible in the design process.

  • 5. Cella, U.
    et al.
    Rizzi, Arthur
    KTH, Superseded Departments, Aeronautical and Vehicle Engineering.
    Sensitivity to physical and numerical modeling in Navier-Stokes simulations2000In: Journal of Aerospace Engineering, ISSN 0893-1321, E-ISSN 1943-5525, Vol. 13, no 2, p. 47-51Article in journal (Refereed)
    Abstract [en]

    Navier-Stokes Multiblock code solves the fully coupled system of equations simultaneously using a cell-centered finite-volume approach. This note assesses the sensitivity to some turbulence models and numerical schemes implemented in Navier-Stokes Multiblock when computing two test cases in standard mode, i.e., without tuning the code to these two cases. The cases are (1) subsonic flow around the MS(1)-0313 airfoil, and (2) transonic flow around the ONERA M6 wing, using various combinations of models (algebraic Baldwin-Lomax or Granville, one-equation Spalart-Allmaras, or the two-equation k - epsilon model of Chien) together with a numerical scheme of either the second-order central or third-order Roe upwind type.

  • 6.
    Crippa, Simone
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Initial Steady and Unsteady CFD Analysis of a Half-span Delta Wing2006In: Proceedings of the 25th Congress of the International Council of the Aeronautical Sciences 2006, 2006Conference paper (Refereed)
  • 7.
    Crippa, Simone
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Initial steady/unsteady CFD analysis of vortex flow over the VFE-2 delta wing2006In: 25th Congress of the International Council of the Aeronautical Sciences, 3-8 September 2006, Hamburg, Germany, 2006, p. 883-892Conference paper (Refereed)
    Abstract [en]

    This study is aimed at assessing the application of the latest unstationary CFD method, Detached- Eddy Simulation (DES), to simulate the flowfield around blunt leading edge delta wings. For this purpose, the Second International Vortex Flow Experiment (VFE-2) 65° sweep delta wing model was used to perform numerical investigations at a Reynolds number of 6 million, Mach number of 0.4 and angles of attack of 18.5° and 23°. As the nature of this study is mainly exploratory, various numerical grids have been used. The results confirm the maturity of Reynolds averaged Navier-Stokes (RANS) methods but also the problems of DES to predict free separation and the grid sensitivity of this model.

  • 8.
    Crippa, Simone
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Numerical investigation of Reynolds number effects on a blunt leading-edge delta wing2006In: 24th AIAA Applied Aerodynamics Conference: San Francisco, CA : 5 June 2006 through 8 June 2006, 2006, p. 708-726Conference paper (Refereed)
    Abstract [en]

    Numerical results are presented and discussed in this paper allowing a deeper and more precise characterization of the unique double vortex system, which develops on the second International Vortex Flow Experiment (VFE-2) blunt leading edge delta wing of 65° sweep. Computational fluid dynamic (CFD) computations have been performed for three Reynolds numbers (2, 6 and 60 million) at three angles of attack (13.3°, 18.5° and 23.0°) for a fixed Mach number of 0.4. Leading edge primary separation onset is shown to match best the available wind tunnel data at the highest investigated Reynolds number of 60 million and at an angle of attack of 23.0°. At this condition, the coupling between outer primary vortex attachment line with the inner primary vortex separation line is clearly recognizable. Only if the inner primary vortex strength is predicted well, the attached flow passing under the inner primary vortex core is accelerated sufficiently to trigger (inner) secondary separation.

  • 9.
    Crippa, Simone
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Reynolds number effects on blunt leading edge delta wings2007In: 1st CEAS European Air and Space Conference: September 2007, Berlin, Germany, 2007Conference paper (Refereed)
  • 10.
    Crippa, Simone
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Steady, subsonic CFD analysis of the VFE-2 configuration and comparison to wind tunnel data2008In: 46th AIAA Aerospace Sciences Meeting and Exhibit, 2008Conference paper (Refereed)
    Abstract [en]

    A steady computational fluid dynamic (CFD) study is performed over a wide range of Reynolds numbers at low incidence and subsonic speeds on the Second International Vortex Flow Experiment (VFE-2) blunt leading-edge delta wing of 65° sweep. The numerical results are presented and compared to experimental data and are further used to understand the formation of a weak, thin vortical structure that develops upstream of primary leading-edge separation onset. Comparisons between computational results and experiments are presented with regard to surface pressure coefficient and surface flow patterns for the suction side of the delta wing. Inviscid computations displaying a similar vortical pattern as the viscous results raise the doubt that time-accurate computations might be necessary to correctly predict the formation of the weak apex vortex.

  • 11. Da Ronch, A.
    et al.
    Ghoreyshi, M.
    Vallespin, D.
    Badcock, K. J.
    Mengmeng, Zhang
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Oppelstrup, Jesper
    KTH, School of Computer Science and Communication (CSC), Numerical Analysis and Computer Science, NADA.
    Rizzi, Arthur W.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    A framework for constrained control allocation using CFD-based tabular data2011In: AIAA Aerosp. Sci. Meet. Incl. New Horiz. Forum Aerosp. Expos., 2011Conference paper (Refereed)
    Abstract [en]

    This paper describes a framework for control allocation problem using Computational Fluid Dynamics (CFD) aerodata, which is represented by a multidimensional array of dimensionless coefficients of aerodynamic forces and moments, stored as a function of the state vector and control-surface deflections. The challenges addressed are, first, the control surface treatment for the automated generation of aerodata using CFD and, second, sampling and data fusion to allow the timely calculation of large data tables. In this framework, the generation of aerodynamic tables is described based on an efficient sampling/data fusion approach. Also, the treatment of aerodynamics of control surfaces is being addressed for three flow solvers: TORNADO, a vortex-lattice method, and two CFD codes, EDGE from the Swedis Defence Agency and PMB from the University of Liverpool. In TORNADO, the vortex points located at the trailing edge of the flaps are rotated around the hinge line to simulate the deflected surfaces. The transpiration boundary conditions approach is used for modeling moving flaps in EDGE, whereas, the surface deflection is achieved using mode shapes in PMB. The test cases used to illustrate the approaches is the Ranger 2000 fighter trainer and a reduced geometry description of Boeing 747-100. Data tables are then generated for the state vector and multiple control surface deflections. The look-up table aerodata are then used to resolve the control allocation problem under the constraint that each surface has an upper and lower limit of deflection angle.

  • 12. Da Ronch, A.
    et al.
    McFarlane, C.
    Beaverstock, C.
    Oppelstrup, Jesper
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Zhang, Mengmeng
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Benchmarking ceasiom software to predict flight control and flying qualities of the B-7472010In: 27th Congress of the International Council of the Aeronautical Sciences 2010, ICAS 2010: Volume 4, 2010, p. 2906-2912Conference paper (Refereed)
    Abstract [en]

    CEASIOM, the Computerized Environment for Aircraft Synthesis and Integrated Optimization Methods, is a framework that integrates discipline-specific tools for conceptual design. At this early stage of the design it is very useful to be able to predict the flying and handling qualities of the aircraft. In order to do this for the configuration being studied, the aerodynamic database needs to be computed and coupled to the stability and control tools to carry out the analysis. This paper describes how the adaptivefidelity CFD module of CEASIOM computes the aerodynamic database of an aircraft configuration, and how that data is analyzed by the FCSDT module to determine the flying qualities and the control laws of the aircraft. The paper compares the predicted flying qualities with the flight-test data of the Boeing B747 aircraft in order to verify the goodness of the overall approach.

  • 13.
    Da Ronch, A.
    et al.
    Department of Engineering, University of Liverpool, UK.
    McFarlane, C.
    Department of Aerospace Engineering, Bristol University, UK.
    Oppelstrup, Jesper
    KTH, School of Computer Science and Communication (CSC), Numerical Analysis, NA.
    Zhang, Mengmeng
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Benchmarking CEASIO software to predict flight control and flying qualities of the B-7472010In: 27th International Congress of the Aeronautical Sciences, ICAS 2010, 2010Conference paper (Refereed)
  • 14. Eliasson, P.
    et al.
    Vos, J. B.
    Da Ronch, A.
    Zhang, Mengmeng
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Virtual aircraft design of transcruiser - Computing break points in pitch moment curve2010In: 28th AIAA Applied Aerodynamics Conference, 2010, p. 2010-4366-Conference paper (Refereed)
    Abstract [en]

    The SimSAC project has developed the design software CEASIOM, a framework tool that integrates discipline-specific tools like CAD & grid generation, CFD, stability & control analysis etc. for the purpose of aircraft conceptual design. Significant features developed and integrated in CEASIOM are geometry, aerodynamics, flight dynamics and aeroelasticity modules. The design begins with a design specification and uses conventional design methods to prescribe a baseline configuration. Then CEASIOM improves upon this baseline by analyzing its flying and handling qualities. This paper reports on the Transonic cruiser TCR from baseline design to Tier-I design. The baseline T-tail design is based on the design specification, which is a fairly non-complicated one with the exception for the design cruise speed of Mach 0.97. The flight dynamical analysis in CEASIOM of this configuration showed that trimming the aircraft required too large deflections in the design point so a new approach with a canard configuration was designed. A model of this configuration was built and tested in wind tunnel. The paper focuses on the validation of computational tools of different fidelity, from Tier I to Tier II RANS solvers, with test data to get a range of fidelity of the tools. The results showed that Tier I methods fail to reproduce experimental pitch moment already at moderate angles of attack. Euler methods give reasonably accurate predictions but only RANS offers good overall experimental agreement for all angles attack, in particular at higher angles where the flow starts to separate.

  • 15. Frink, N. T.
    et al.
    Tomac, Maximillian
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Collaborative study of incipient separation on 53°-swept diamond wing2016In: Aerospace Science and Technology, ISSN 1270-9638, E-ISSN 1626-3219Article in journal (Refereed)
    Abstract [en]

    A systematic analysis of incipient separation and subsequent vortex formation from moderately-swept blunt leading edges is presented for a 53°-swept diamond wing. This work contributes to a collective body of knowledge generated within the multinational NATO/STO AVT-183 Task Group titled "Reliable Prediction of Separated Flow Onset and Progression for Air and Sea Vehicles". Details of vortex formation are inferred from numerical solutions of two flow solvers after establishing a good correlation of the global flow field and surface pressure distributions with those from wind tunnel measurements. From this, significant and sometimes surprising insights into the nature of incipient separation and part-span vortex formation are derived from the wealth of information available in the computational solutions.

  • 16. Ghoreyshi, M.
    et al.
    Badcock, K. J.
    Da Ronch, A.
    Vallespin, D.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Automated CFD Analysis for the Investigation of Flight Handling Qualities2011In: Mathematical Modelling of Natural Phenomena, ISSN 0973-5348, E-ISSN 1760-6101, Vol. 6, no 3, p. 166-188Article in journal (Refereed)
    Abstract [en]

    Physics based simulation is widely seen as a way of increasing the information about aircraft designs earlier in their definition, thus helping with the avoidance of unanticipated problems as the design is refined. This paper reports on an effort to assess the automated use of computational fluid dynamics level aerodynamics for the development of tables for flight dynamics analysis at the conceptual stage. These tables are then used to calculate handling qualities measures. The methodological questions addressed are a) geometry and mesh treatment for automated analysis from a high level conceptual aircraft description and b) sampling and data fusion to allow the timely calculation of large data tables. The test case used to illustrate the approaches is based on a refined design passenger jet wind tunnel model. This model is reduced to a conceptual description, and the ability of this geometry to allow calculations relevant to the final design to be drawn is then examined. Data tables are then generated and handling qualities calculated.

  • 17. Ghoreyshi, M.
    et al.
    Da Ronch, A.
    Badcock, K. J.
    Dees, J.
    Bérard, Adrien
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Aerodynamic modelling for flight dynamics analysis of conceptual aircraft designs2009In: 27th AIAA Applied Aerodynamics Conference, 2009Conference paper (Refereed)
    Abstract [en]

    Physics based simulation in conceptual design is widely seen as a way of increasing the information about designs, thus helping with the avoidance of unanticipated problems as the design is refined. This paper reports on an effort to assess the use of CFD level aerodynamics for the development of tables for flight dynamics analysis at the conceptual stage. A number of aerodynamic data sources are used with sampling and data fusion to allow the efficient generation of the tables. A refined design passenger jet wind tunnel model is used as a test case, and three simplified conceptual versions of this geometry are generated. The influence of geometry approximations and modelling influences are evaluated to assess the usefulness of CFD for this application. Finally, the aerodynamic differences are assessed in terms of basic longitudinal flight dynamics analysis.

  • 18.
    Goetzendorf-Grabowski, Tomas
    et al.
    Institute of Aeronautics & Applied Mechanics, Aircraft Design Department, Warsaw University of Technology, 00-665 Warsaw, Poland.
    Vosy, J.B.
    Sanchiz, S.
    Molitor, Paul
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Tomac, Maximilian
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Coupling Adaptive-Fidelity CFD with S&C Analysis to Predict Flying Qualities2009In: 27th AIAA Applied Aerodynamics Conference, 2009Conference paper (Refereed)
    Abstract [en]

    CEASIOM, the Computerized Environment for Aircraft Synthesis and Integrated Optimization Methods, is a framework tool that integrates discipline-specific tools for conceptual design. At this early stage of the design it is very useful to be able to predict the °ying and handling qualities of this design. In order to do this, the aerodynamic database needs to be computed for the configuration being studied which then has to be coupled to the stability and control tools to carry out the analysis. This paper describes how the adaptive-fidelity CFD module of CEASIOM computes the aerodynamic dataset of an air craft configuration, and how that dataset is analyzed by the SDSA module to determine the °ying qualities of the aircraft. These predicted °ying qualities are then compared with the °ight-test data of the Ranger 2000 trainer aircraft in order to verify the goodness of the overall approach.

  • 19.
    Görtz, Stefan
    et al.
    KTH, Superseded Departments, Aeronautical and Vehicle Engineering.
    Rizzi, Arthur
    KTH, Superseded Departments, Aeronautical and Vehicle Engineering.
    Computing the High-Alpha Aerodynamics of Delta Wings: Evaluation and Analysis2001Conference paper (Other academic)
  • 20.
    Görtz, Stefan
    et al.
    KTH, Superseded Departments, Aeronautical and Vehicle Engineering.
    Rizzi, Arthur
    KTH, Superseded Departments, Aeronautical and Vehicle Engineering.
    Munukka, K.
    Saab Aerospace.
    Computational Study of Vortex Breakdown over Swept Delta Wings1999Conference paper (Other academic)
  • 21. Irving, J. P.
    et al.
    Vicroy, D. D.
    Farcy, D.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Development of an aerodynamic simulation model of a generic configuration for S&C analyses2014In: 32nd AIAA Applied Aerodynamics Conference, 2014Conference paper (Refereed)
    Abstract [en]

    The development of an aerodynamic simulation model for the inclusion in an open-loop Stability & Control model is presented. The model, based on a generic UCAV configuration, is derived from data gathered during a number of experimental campaigns conducted using various test models and facilities, and covers the full subsonic flight regime. The model includes uncertainties in key model parameters to yield an expected range of model outputs for any given condition.

  • 22.
    Jiràsek, Adam
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Libm3l and lsipdx-utilities for inter-process data transfer and synchronization2014In: 52nd Aerospace Sciences Meeting, American Institute of Aeronautics and Astronautics, 2014Conference paper (Refereed)
    Abstract [en]

    This paper describes two Open Source Software libraries which are currently under development-libm3l and lsipdx. The libm3l library is a utility enabling storage of the basic data types in a linked list and their transfer through the TCP/IP socket. The linked list can be transferred as a whole or just its part. The second utility, the lsipdx library, is a utility which enables transfer of the data among a number of processes and their synchronization. The libraries are therefore suitable candidate for data exchange and synchronization of a number of solvers in the multidisciplinary analysis. Both libraries are written in the ANSI-C programming language and are available to the public under GNU Lesser GPL, LGPL, license through the github site.

  • 23.
    Jirásek, Adam
    et al.
    FOI.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Numerical Solutions for the Cawapi Configuration on Unstructured Grids at KTH/FOI, Sweden: Part II2009In: Understanding and Modeling Vortical Flows to Improve the Technology Readiness Level for Military Aircraft, 2009Chapter in book (Other academic)
    Abstract [en]

    This article represents a second contribution of the Swedish Defence Research Agency, FOI, and the Royal Institute of Technology, KTH, to the Cranked-Arrow Wing Aerodynamics Project International, CAWAPI. The main focus of this article is on evaluation of the effect of different formulation of boundary conditions on the engine mass flow and resulting wing upper surface pressures.

  • 24. Luckrin, J. M.
    et al.
    Park, M. A.
    Hitzel, S. M.
    Jirásek, A.
    Lofthouse, A. J.
    Morton, S. A.
    McDaniel, D. R.
    Rizzi, Arthur
    Tomac, M.
    A synthesis of hybrid RANS/LES CFD results for F-16XL aircraft aerodynamics2015In: 33rd AIAA Applied Aerodynamics Conference, American Institute of Aeronautics and Astronautics, 2015Conference paper (Refereed)
    Abstract [en]

    A synthesis is presented of recent numerical predictions for the F-16XL aircraft flow fields and aerodynamics. The computational results were all performed with hybrid RANS/LES formulations, with an emphasis on unsteady flows and subsequent aerodynamics, and results from five computational methods are included. The work was focused on one particular low-speed, high angle-of-attack flight test condition, and comparisons against flight-test data are included. This work represents the third coordinated effort using the F-16XL aircraft, and a unique flight-test data set, to advance our knowledge of slender airframe aerodynamics as well as our capability for predicting these aerodynamics with advanced CFD formulations. The prior efforts were identified as Cranked Arrow Wing Aerodynamics Project International, with the acronyms CAWAPI and CAWAPI-2.

  • 25. Luckring, J. M.
    et al.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Bruce Davis, M.
    Toward improved CFD predictions of slender airframe aerodynamics using the F-16XL aircraft (CAWAPI-2)2014In: 52nd AIAA Aerospace Sciences Meeting - AIAA Science and Technology Forum and Exposition, SciTech 2014, 2014Conference paper (Refereed)
    Abstract [en]

    A coordinated project has been underway to improve CFD predictions of slender airframe aerodynamics. The work is focused on two flow conditions and leverages a unique flight data set obtained with an F-16XL aircraft. These conditions, a low-speed high angle-of-attack case and a transonic low angle-of-attack case, were selected from a prior prediction campaign wherein the CFD failed to provide acceptable results. In this paper the background, objectives and approach to the current project are presented. The work embodies predictions from multiple numerical formulations that are contributed from multiple organizations, and the context of this campaign to other multi-code, multi-organizational efforts is included. The relevance of this body of work toward future supersonic commercial transport concepts is also briefly addressed.

  • 26. Luckring, James M.
    et al.
    Park, Michael A.
    Hitzel, Stephan M.
    Jirasek, Adam
    Lofthouse, Andrew J.
    Morton, Scott A.
    McDaniel, David R.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. Univ Alabama Birmingham, USA.
    Tomac, Maximillian
    Synthesis of Hybrid Computational Fluid Dynamics Results for F-16XL Aircraft Aerodynamics2017In: Journal of Aircraft, ISSN 0021-8669, E-ISSN 1533-3868, Vol. 54, no 6, p. 2100-2114Article in journal (Refereed)
    Abstract [en]

    A synthesis is presented of recent numerical predictions for the F-16XL aircraft flowfields and aerodynamics. The computational analyses were all performed with hybrid Reynolds-averaged Navier-Stokes/large-eddy simulation formulations, with an emphasis on unsteady flows and associated aerodynamics, and results from five computational methods are included. The work focused on one particular low-speed high angle-of-attack flight-test condition, and comparisons against flight-test data are included. This work represents the third coordinated effort using the F-16XL aircraft, and a unique flight-test dataset, to advance the knowledge of slender airframe aerodynamics as well as the capability for predicting these aerodynamics with advanced computational fluid dynamics formulations. The prior efforts were identified as the Cranked-Arrow Wing Aerodynamics Project International.

  • 27.
    Macchion, Olivier
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Lior, Noam
    KTH, School of Engineering Sciences (SCI), Centres, Faxén Laboratory.
    Computational Study of Velocity Distribution for Designing some Gas Quench Chamber and Furnace Ducts2005In: Journal of Materials Processing Technology, ISSN 0924-0136, E-ISSN 1873-4774, Vol. 155, no Part 2 Sp. Iss. SI, p. 1727-1733Article in journal (Refereed)
    Abstract [en]

    Gas cooled quenching and many other applications require high-speed uniform-velocity flows, with minimal pressure drop. The flow ducting geometry is often rather complex, with flow splitting, 90-180 degrees bends, and circular-to-rectangular cross-section transition ducts (the latter are used, for example, between the circular blower duct and the rectangular quenching baskets). Similar situations exist in forced convection furnaces. To provide design guidance in the choice of such ducts, and focusing primarily on circular-to-rectangular transition ducts. the flow was modelled and computed, and the results were successfully validated. Sensitivity of the velocity uniformity and pressure drop with respect to the primary geometric parameters, pressure, and Reynolds numbers was examined in the range (1.3) 10(5) # Re # (7.8)10(5), with an ultimate objective to produce optimal designs. For a length-to-diameter ratio AL = L/D < 1.0, flow nonuniformity at the exit plane and pressure drop are increased by 33 and 83%, respectively, as the aspect ratio (rectangular duct width-to-height) AR decreases from 4 to 1. Increasing AR beyond 1.5 leads to linearly increasing nonuniformity and pressure drops. A diverging-contracting duct has proven to lead to lesser nonuniformity, while it did not influence the pressure drop. Increasing the inlet pressure from 1 to 20 bar led to a decrease in flow distortion by 11% at the duct exit planes. At atmospheric pressure, increasing the Reynolds number from (1.3)10(5) to (7.8)10(5) increased distortion by 8%. Some preliminary design recommendations for circular-to-rectangular duct transitions are to try and keep AL > 1 and AR < 1.5.

  • 28.
    Melin, Tomas
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Stamblevski, Christopher
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Isikveren, Askin
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Anders, Hanyo V.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    How Industry Concepts of Concurrent Engineering Enhances Aircraft Design Education2007In: Proceedings of the Institution of Mechanical Engineers. Part G, Journal of Aerospace Engineering, ISSN 0954-4100, E-ISSN 2041-3025, Vol. 221, no 2, p. 175-192Article in journal (Refereed)
    Abstract [en]

    Two student projects are described including the intended goals, the approaches taken, the tools used, and what was learned from the exercises. An international collaborative teaching protocol between Ecole Polytechnique de Montreal and the Royal Institute of Technology (KTH) was exercised in aircraft design education. Poignantly, a novel instructive design process using the analogue of contemporary concurrent engineering practices in industry was implemented. The idea was to strategically assign multi-disciplinary design tasks to each Partner University in accordance with their respective competencies. The university-industry coupling was initiated by request for proposals and corresponding marketing requirements and objectives produced by Bombardier Aerospace in Montreal, Canada. Two MATLAB™-based tools were prominent in facilitating the capstone aircraft design projects. They included: Quick Conceptual Aircraft Research and Design, a computer-aided conceptual design engineering system; and TORNADO, a Vortex-Lattice code for computing aerodynamic characteristics. The result of the two exercises was found to benefit the participating industry, the educational establishments involved, and the students carrying out the projects.

  • 29. Mendenhall, M.R.
    et al.
    Perkins, S.C.
    Tomac, Maximilian
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Nangia, Raj K.
    Nangia Aero Research Associates.
    Comparing and benchmarking engineering methods for the prediction of X-31 aerodynamics2012In: Aerospace Science and Technology, ISSN 1270-9638, E-ISSN 1626-3219, Vol. 20, no 1, p. 12-20Article in journal (Refereed)
    Abstract [en]

    A number of useful engineering methods are available for fast and economic estimates of the aerodynamic characteristics of complex flight vehicles. This article investigates the application of three specific engineering methods to the X-31 fighter configuration, and CFD, wind tunnel, and flight test data are used for comparison and evaluation purposes. The emphasis is on static longitudinal stability aspects up to high angles of attack; however, selected asymmetric and unsteady effects are considered. Results from the engineering methods are in good agreement with experiment and CFD for angles of attack up to 15° for most cases and higher angles for some cases. Results for pitching moment are in good agreement with CFD, but many of the nonlinear characteristics of the airplane are not predicted by the engineering methods. The quality of the longitudinal stability results is discussed in terms of the prediction of the center of pressure on the vehicle. The results provide improved understanding of the continued usefulness of engineering methods as an analysis tool during the design phase and into the flight test diagnostic phase of a new aircraft.

  • 30.
    Mengmeng, Zhang
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Nangia, R.
    Transonic airfoil and wing design using inverse and direct methods2015In: 53rd AIAA Aerospace Sciences Meeting, Kissimmee, Florida: American Institute of Aeronautics and Astronautics, 2015Conference paper (Refereed)
    Abstract [en]

    A hybrid inverse/direct-optimization method for subsonic/transonic airfoil and wing shape design is presentedwith application to a range of airfoil and wing cases, in preparation for the test cases defined for the Special Sessionof SciTech 2015. The method is hybrid in the sense that it combines the traditional inverse design technique witha gradient-based procedure to approach the optimum aerodynamic surface. This paper emphasizes the first part, thedevelopment of SCID, the Surface Curvature Inverse Design method, the theory upon which it is based, includingmany of the details involved with shocks, smoothing and cross flow. The application of SCID to wing design posesmany challenges, and how they are met is discussed in the context of a number of inverse design test cases for airfoilsand wings. But it also includes results from the adjoint optimization and compares them. The procedure workswell for airfoils and the twist optimization for wings. The real benchmarks for our hybrid approach are the threeOptimization Discussion Group design problems. Solutions are presented for the drag minimization of the airfoil testcases along with the wing twist optimization problem, and conclusions are drawn from the results obtained. A swept-back transonic wing is designed by SCID with encouraging results, showing that SCID works fine with wings. Workhas started on the drag minimization of the CRM wing in transonic flight, and final results will be presented in a futurepaper.

  • 31.
    Mengmeng, Zhang
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Raymer, D.
    Enhancement of CEASIOM with Rapid-Meshing Tool for Aircraft Conceptual Design2012In: The journal of Aerospace Science, Technology and Systems, Vol. 91, no 3/4, p. 79-85Article in journal (Refereed)
    Abstract [en]

    This paper details the development and application of the RDS-SUMO-CEASIOM-EDGE rapid-CFD tool. It uses theRDS CAD model as geometry for automated meshing and CFD analysis to produce an aero-data base for control andstability analysis. It is applied to two non-conventional design proposals, an asymmetric twin-prop aircraft and anairliner with rear Open Rotor propulsion, retractable canard, and a “chin-rudder” instead of vertical tail. For bothconfigurations,yaw control is problematic, and the stability and control analysis is used to assess control surface sizing and stabilityaugmentation system.

  • 32. Nagel, B.
    et al.
    Böhnke, D.
    Gollnick, V.
    Schmollgruber, P.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    La Roccax, G.
    Alonso, J. J.
    Communication in aircraft design: Can we establish a common language?2012In: 28th Congress of the International Council of the Aeronautical Sciences 2012, ICAS 2012: Volume 1, 2012, p. 443-455Conference paper (Refereed)
    Abstract [en]

    A standardized data model as common language for disciplinary communication in aircraft design could have a significant impact on the efficiency of conceptual/preliminary design efforts and collaborative research in aircraft design. This paper discusses if such a standard could be established and under which circumstances this would make sense. The Common Parametric Aircraft Configuration Scheme (CPACS) is introduced as one potential step towards a unified data model. Experiences in coupling established Multidisciplinary Design Optimization (MDO) environments with CPACS are presented and requirements for setting a standard are discussed.

  • 33.
    Pettersson, Karl
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Aerodynamic scaling to free flight conditions: past and present2008In: Progress in Aerospace Sciences, ISSN 0376-0421, E-ISSN 1873-1724, Vol. 44, no 4, p. 295-313Article in journal (Refereed)
    Abstract [en]

    This report summarizes some of the problems when wind tunnel data should be scaled to free flight conditions. The main challenges in performing this extrapolation is how model support, wall interference, aeroelastic effects and a potentially lower Reynolds number in the wind tunnel should be corrected. A historical review of scale effects is presented showing wind tunnel to flight discrepancies of different types of aircraft configurations. An overview of scaling methodologies and Reynolds number effects are presented and discussed. Some modern approaches where computational fluid dynamics (CFD) are used, together with wind tunnel testing, in order to identify scaling phenomena are presented as well.

  • 34.
    Pettersson, Karl
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Comparing different CFD methods accuracy in computing local boundary layer properties2009In: Engineering Applications of Computational Fluid Mechanics, ISSN 1994-2060, Vol. 3, no 1, p. 98-108Article in journal (Refereed)
    Abstract [en]

    In aeronautical applications wind tunnels are often not capable of producing high Reynolds numbers which are achieved at free flight conditions. Today CFD methods are often used as a tool to estimate scale effects. CFD methods are commonly used to predict flow features at Reynolds numbers higher than what the aircraft model is subject to in the wind tunnel, and at higher Reynolds number than the turbulence model has been calibrated to. The investigation of local boundary layer properties could give useful information when the wind tunnel data is scaled to free flight conditions the question is whether the CFD methods compute these in a consistent manner when there is a large spread in Reynolds number. This work compares two different CFD solvers and two different turbulence models' accuracy in computing local boundary layer properties compared to wind tunnel measurements.

  • 35.
    Pettersson, Karl
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Estimating local boundary layer properties using CFD and wind tunnel measurementsManuscript (Other academic)
  • 36.
    Pettersson, Karl
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Estimating Reynolds number scaling and windtunnel boom effects with the help of CFD methods2006In: Collection of Technical Papers - AIAA Applied Aerodynamics Conference, 2006, p. 889-895Conference paper (Refereed)
    Abstract [en]

    In order to estimate the aerodynamic effects of the twin sting booms in the European Transonic Wind Tunnel (ETW) on a transonic transport aircraft CFD calculations have been performed. The CFD calculations have been done solving the RANS equations on an unstructured grid for the aircraft with and without booms mounted and for varying Reynolds number. The two sets of data (booms on and booms off) enables comparisons, isolating booms and Reynolds number effects and conclusions can be drawn. These conclusions might give information about how the free flight aircraft would differ from the wind tunnel data.

  • 37.
    Pettersson, Karl
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Implementation and Evaluation of Different Preconditioning Methods in the Compressible CFD Solver Edge2008In: 5th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2008), 2008Conference paper (Refereed)
  • 38.
    Pettersson, Karl
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Reynolds number effects identified with CFD methods compared to semi-empirical methods2006In: ICAS-Secretariat - 25th Congress of the International Council of the Aeronautical Sciences 2006, Curran Associates, Inc., 2006, Vol. 3, p. 1566-1579Conference paper (Refereed)
    Abstract [en]

    In order to estimate Reynolds number effects on a transonic transport aircraft CFD calculations have been performed. The CFD calculations have been done solving the RANS equations on an unstructured grid for varying Reynolds number at transonic conditions. Low Reynolds number data have been extrapolated to a higher Reynolds number condition with different scaling methodologies in order to evaluate each methods strengths and weaknesses.

  • 39.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Modeling and simulating aircraft stability & control - The SimSAC project2010In: AIAA Atmospheric Flight Mechanics Conference 2010, 2010Conference paper (Refereed)
    Abstract [en]

    This paper overviews the SimSAC Project, Simulating Aircraft Stability And Control Characteristics for Use in Conceptual Design. It reports on the three major tasks: Development of design software, validating the software on benchmark tests and applying the software to design exercises. CEASIOM, the Computerized Environment for Aircraft Synthesis and Integrated Optimization Methods, is a framework tool that integrates discipline-specific tools for conceptual design. At this early stage of the design it is very useful to be able to predict the flying and handling qualities of this design. In order to do this, the aerodynamic database needs to be computed for the configuration being studied which then has to be coupled to the stability and control tools to carry out the analysis. The benchmarks for validation are the F12 windtunnel model of a generic long-range airliner and the TCR windtunnel model of a sonic-cruise passenger transport concept. The design, simulate and evaluate (DSE) exercise demonstrates how the software works as a design tool. The exercise begins with a design specification and uses conventional design methods to prescribe a baseline configuration. Then CEASIOM improves upon this baseline by analyzing its flying and handling qualities. Six such exercises are presented.

  • 40.
    Rizzi, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Modeling and simulating aircraft stability and control-The SimSAC project2011In: Progress in Aerospace Sciences, ISSN 0376-0421, E-ISSN 1873-1724, Vol. 47, no 8, p. 573-588Article, review/survey (Refereed)
    Abstract [en]

    This paper overviews the SimSAC Project, Simulating Aircraft Stability And Control Characteristics for Use in Conceptual Design. It reports on the three major tasks: development of design software, validating the software on benchmark tests and applying the software to design exercises. CEASIOM, the Computerized Environment for Aircraft Synthesis and Integrated Optimization Methods, is a framework tool that integrates discipline-specific tools for conceptual design. At this early stage of the design it is very useful to be able to predict the flying and handling qualities of this design. In order to do this, the aerodynamic database needs to be computed for the configuration being studied, which then has to be coupled to the stability and control tools to carry out the analysis. The benchmarks for validation are the F12 windtunnel model of a generic long-range airliner and the TCR windtunnel model of a sonic-cruise passenger transport concept. The design, simulate and evaluate (DSE) exercise demonstrates how the software works as a design tool. The exercise begins with a design specification and uses conventional design methods to prescribe a baseline configuration. Then CEASIOM improves upon this baseline by analyzing its flying and handling qualities. Six such exercises are presented.

  • 41.
    Rizzi, Arthur
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Boelens, O.
    Jirasek, A.
    Badcock, K.
    What was learned from numerical simulations of F-16XL (CAWAPI) at flight conditions2007In: Collection of Technical Papers - 45th AIAA Aerospace Sciences Meeting, 2007, p. 8385-8420Conference paper (Refereed)
    Abstract [en]

    Ten groups participating in the CAWAPI project have contributed steady and unsteady viscous simulations of a full-scale, semi-span model of the F-16XL-I aircraft at three different categories of flight Reynolds/Mach number combinations for comparison with flight-test measurements for purposes of code validation and improved understanding of the flight physics of complex interacting vortical flows. The steady-state simulations are done with several turbulence models of different complexity with no topology information required and which overcome Boussinesq-assumption problems in vortical flows. Detached-Eddy Simulation (DES) has been used to compute the unsteady flow. Common structured and unstructured grids as well as individually-adapted unstructured grids have been used. Although discrepancies are observed in the comparisons, overall reasonable agreement is demonstrated for surface pressure distribution, local skin friction and boundary velocity profiles. The physical modeling, steady or unsteady, and the grid resolution both contribute to the discrepancies observed in the comparisons with flight data, but at this time it cannot be determined how much each part contributes to the whole. Overall it can be said that the technology readiness of CFD-simulation technology for the study of vehicle performance of e.g. the F-16XL has matured since 2001 such that it can be used today with a reasonable level of confidence in practical use.

  • 42.
    Rizzi, Arthur
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Eliasson, P.
    McFarlane, C.
    Goetzendorf-Grabowski, T.
    Vos, J.
    Virtual-aircraft design & control of TransCruiser - A canard configuration2010In: AIAA Atmospheric Flight Mechanics Conference 2010, 2010Conference paper (Refereed)
    Abstract [en]

    The SimSAC project has developed the design software CEASIOM, a framework tool that integrates discipline-specific tools like: CAD & grid generation, CFD, stability & control analysis etc., all for the purpose of aircraft conceptual design. Significant features developed and integrated in CEASIOM are geometry, aerodynamics, flight dynamics and aeroelasticity modules. The design, simulate and evaluate (DSE) exercise demonstrates how the software works. It begins with a design specification and uses conventional design methods to prescribe a baseline configuration. Then CEASIOM improves upon this baseline by analyzing its flying and handling qualities. This paper reports on the DSE case Transonic cruiser TCR from re-design of the baseline configuration to wind-tunnel model construction and testing, to improving its flying qualities by augmented-stability techniques. The wind-tunnel testing on the model verifies the final design obtained with CEASIOM. This DSE exercise demonstrates how CEASIOM is becoming a useful tool for aircraft conceptual design.

  • 43.
    Rizzi, Arthur
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Eliasson, Peter
    Department of Aeronautics & Systems Technology, FOI, Swedish Defense Research Institute, Stockholm, Sweden.
    Goetzendorf-Grabowski, Tomasz
    Institute of Aeronautics & Applied Mechanics, Aircraft Design Department Warsaw University of Technology, Poland.
    Vos, Jan B.
    CFS Engineering, Lausanne, Switzerland.
    Zhang, Mengmeng
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Virtual-aircraft design & control of transcruiser: a canard configuration2011In: Progress in Aerospace Sciences, ISSN 0376-0421, E-ISSN 1873-1724Article in journal (Other academic)
  • 44.
    Rizzi, Arthur
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Eliasson, Peter
    Goetzendorf-Grabowski, Tomasz
    Vos, Jan B.
    Zhang, Mengmeng
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Richardson, Thomas S.
    Design of a canard configured TransCruiser using CEASIOM2011In: Progress in Aerospace Sciences, ISSN 0376-0421, E-ISSN 1873-1724, Vol. 47, no 8, p. 695-705Article, review/survey (Refereed)
    Abstract [en]

    CEASIOM is a multidisciplinary software environment for aircraft design that has been developed as part of the European Framework 6 SimSAC project. It closely integrates discipline-specific tools such as those used for CAD, grid generation, CFD, stability analysis and control system design. The environment allows the user to take an initial design from geometry definition and aerodynamics generation through to full six degrees of freedom simulation and analysis. Key capabilities include variable fidelity aerodynamics tools and aeroelasticity modules. The purpose of this paper is to demonstrate the potential of CEASIOM by presenting the results of a Design, Simulate and Evaluate (DSE) exercise applied to a novel, project specific, transonic cruiser configuration called the TCR. The baseline TCR configuration is first defined using conventional methods, which is then refined and improved within the CEASIOM software environment. A wind tunnel model of this final configuration was then constructed, tested and used to verify the results generated using CEASIOM.

  • 45.
    Rizzi, Arthur
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Goetzendorf-Grabowski, Tomasz
    Institute of Aeronautics & Applied Mechanics, Aircraft Design Department, Warsaw University of Technology, 00-665 Warsaw, Poland.
    Vos, Jan
    Reating Aero-Databases by Adaptive-Fidelity CFD Coupled with S&C Analysis to Predict Flying Qualities2009In: CEAS European Air & Space Conference, 2009Conference paper (Refereed)
  • 46.
    Rizzi, Arthur
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Hirschel, E. H.
    General developments of numerical fluid mechanics until the middle of the 20th century2009In: 100 Volumes of ‘Notes on Numerical Fluid Mechanics’: 40 Years of Numerical Fluid Mechanics and Aerodynamics in Retrospect, Springer, 2009, p. 61-76Chapter in book (Refereed)
    Abstract [en]

    Today's computational methods are built upon physical and numerical models. Thus it is important to have an appreciation of the reasoning and thought processes that established our current understanding of the mechanics of fluids, all put in place before the age of numerical solutions. A brief sketch is given of the evolution of the ideas that led to the formulation of the equations governing fluid flow, the problems to which the equations were applied, and the efforts to solve them before computers were available. After the historical origins of the fluid-flow models are in place, the last section traces the transition undergone during the 20th Century, starting with analytical means to solve the mathematical problems that successively evolved into numerical approaches to solving them, thus leading up to the present time of the computational era.

  • 47.
    Rizzi, Arthur
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Jirásek, A.
    Cavagna, L.
    Riccobene, L.
    Ricc, S.
    Aeroelastic analysis of the CAWAPI F-16XL configuration at transonic speeds2014In: 52nd AIAA Aerospace Sciences Meeting - AIAA Science and Technology Forum and Exposition, SciTech 2014, 2014Conference paper (Refereed)
    Abstract [en]

    This article present an aeroelastic study of CAWAPI F-16XL aircraft. The structural model for this aircraft is publicly available and is therefore replaced by a structural model estimate which is constructed based on data available in public literature. The aeroelastic solution is done using inviscid solution for two flight conditions - FC70 and FC79. The primary task is to assess importance of the aeroelastic effects on the solution and to asses weather large discrepancies observed at flight condition FC70 between the computational and experimental data.

  • 48.
    Rizzi, Arthur
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Jirásek, Adam
    Swedish Def Res Agcy, Div Syst Technol.
    Lamar, John
    NASA, Langley Res Ctr.
    Crippa, Simone
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Badcock, Ken
    Univ Liverpool, Dept Engn.
    Boelens, Okko
    NLR, Natl Aerosp Lab, Dept Flight Phys & Loads, Aerosp Vehicles Div.
    Lessons learned from numerical simulations of the F-16XL at flight conditions2009In: Journal of Aircraft, ISSN 0021-8669, E-ISSN 1533-3868, Vol. 46, no 2, p. 423-441Article in journal (Refereed)
    Abstract [en]

    Nine organizations participated in the Cranked-Arrow Wing Aerodynamics Project International study and have contributed steady and unsteady viscous simulations of a full-scale semispan model of the F-16XL aircraft. Three different categories of flight Reynolds/Mach number combinations are computed and compared with flight-test measurements for the purpose of code validation and improved understanding of the flight physics. Steady-state simulations are done with several turbulence models (of different complexity, with no topology information required) that overcome Boussinesq-assumption problems in vortical flows. Detached-eddy simulation and its successor, delayed detached-eddy simulation, are used to compute the time-accurate flow development. Common structured and unstructured grids as well as individually adapted unstructured grids were used. Although discrepancies are observed in the comparisons, overall reasonable agreement is demonstrated for surface pressure distribution, local skin friction, and boundary velocity profiles at subsonic speeds. The physical modeling, be it steady or unsteady flow, and the grid resolution both contribute to the discrepancies observed in the comparisons with flight data, but at this time, how much each part contributes to the whole cannot be determined. Overall, it can be said that the technology readiness of computational fluid dynamics simulation technology for the study of vehicle performance has matured since 2001, such that it can be used today with a reasonable level of confidence for complex configurations.

  • 49.
    Rizzi, Arthur
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Luckring, J. M.
    What was learned in predicting slender airframe aerodynamics with the F16-XL aircraft2014In: 52nd AIAA Aerospace Sciences Meeting - AIAA Science and Technology Forum and Exposition, SciTech 2014, 2014Conference paper (Refereed)
    Abstract [en]

    The CAWAPI-2 coordinated project has been underway to improve CFD predictions of slender airframe aerodynamics. The work is focused on two flow conditions and leverages a unique flight data set obtained with the F-16XL aircraft for comparison and verification. These conditions, a low-speed high angle-of-attack case and a transonic low angle-of-attack case, were selected from a prior prediction campaign wherein the CFD failed to provide acceptable results. In re-visiting these two cases, approaches for improved results include better, denser grids using more grid adaptation to local flow features as well as unsteady higher-fidelity physical modeling like hybrid RANS/URANS-LES methods. The work embodies predictions from multiple numerical formulations that are contributed from multiple organizations where some authors investigate other possible factors that could explain the discrepancies in agreement, e.g. effects due to deflected control surfaces during the flight tests, as well as static aeroelastic deflection of the outer wing. This paper presents the synthesis of all the results and findings and draws some conclusions that lead to an improved understanding of the underlying flow physics, and finally making the connections between the physics and aircraft features.

  • 50.
    Rizzi, Arthur
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Luckring, James M.
    What Was Learned in Predicting Slender Airframe Aerodynamics with the F-16XL Aircraft2017In: Journal of Aircraft, ISSN 0021-8669, E-ISSN 1533-3868, Vol. 54, no 2, p. 444-455Article in journal (Refereed)
    Abstract [en]

    The second Cranked-Arrow Wing Aerodynamics Project, International, coordinated project has been underway to improve high-fidelity computational-fluid-dynamics predictions of slender airframe aerodynamics. The work is focused on two flow conditions and leverages a unique flight data set obtained with the F-16XL aircraft for comparison and validation. These conditions, a low-speed high-angle-of-attack case and a transonic low-angle-of-attack case, were selected from a prior prediction campaign wherein the computational fluid dynamics failed to provide acceptable results. In revisiting these two cases, approaches for improved results include better, denser grids using more grid adaptation to local flow features as well as unsteady higher-fidelity physical modeling like hybrid Reynolds-averaged Navier-Stokes/unsteady Reynolds-averaged Navier-Stokes/large-eddy simulation methods. The work embodies predictions from multiple numerical formulations that are contributed from multiple organizations where some authors investigate other possible factors that could explain the discrepancies in agreement (e.g., effects due to deflected control surfaces during the flight tests as well as static aeroelastic deflection of the outer wing). This paper presents the synthesis of all the results and findings and draws some conclusions that lead to an improved understanding of the underlying flow physics, finally making the connections between the physics and aircraft features.

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