Airinnova is a start-up company with a key competency in the automation of high-fidelity computational fluid dynamics (CFD) analysis. Following on from our previous PRACE SHAPE project, we have continued collaborating with the PDC Center for High Performance Computing at the KTH Royal Institute of Technology (KTH-PDC), to investigate the performance analysis of the open source CFD code SU2 and further develop the automation process for the field of aerodynamic optimization and design.

Automatic multidisciplinary design optimization is one of the challenges that are faced in the processes involved in designing efficient wings for aircraft. In this paper we present mixed fidelity aerodynamic and aero-structural optimization methods for designing wings. A novel shape design methodology has been developed - it is based on a mix of the automatic aerodynamic optimization for a reference aircraft model, and the aero-structural optimization for an uninhabited air vehicle (UAV) with a high aspect ratio wing. This paper is a significant step towards making it possible to perform all the core processes for aerodynamic and aero-structural optimization that require special skills in a fully automatic manner - this covers all the processes from creating the mesh for the wing simulation to executing the high-fidelity computational fluid dynamics (CFD) analysis code. Our results confirm that the simulation tools can make it possible for a far broader range of engineering researchers and developers to design aircraft in much simpler and more efficient ways. This is a vital step in the evolution of wing design processes as it means that the extremely expensive laboratory experiments that were traditionally used when designing the wings can now be replaced with more cost effective high performance computing (HPC) simulation that utilize accurate numerical methods.

Purpose - A collaborative design environment is needed for multidisciplinary design optimization (MDO) process, based on all the modules those for different design/analysis disciplines, and a systematic coupling should be made to carry out aerodynamic shape optimization (ASO), which is an important part of MDO. Design/methodology/approach - Computerized environment for aircraft synthesis and integrated optimization methods (CEASIOM)-ASO is developed based on loosely coupling all the existing modules of CEASIOM by MATLAB scripts. The optimization problem is broken down into small sub-problems, which is called "sequential design approach", allowing the engineer in the loop. Findings - CEASIOM-ASO shows excellent design abilities on the test case of designing a blended wing body flying in transonic speed, with around 45 per cent drag reduction and all the constraints fulfilled. Practical implications - Authors built a complete and systematic technique for aerodynamic wing shape optimization based on the existing computational design framework CEASIOM, from geometry parametrization, meshing to optimization. Originality/value - CEASIOM-ASO provides an optimization technique with loosely coupled modules in CEASIOM design framework, allowing engineer in the loop to follow the "sequential approach" of the design, which is less "myopic" than sticking to gradient-based optimization for the whole process. Meanwhile, it is easily to be parallelized.

Airinnova is a start-up company with a key competency in the automation of high fidelity computational fluiddynamics (CFD) analysis. The goal of this SHAPE project, a collaboration with the PDC Center for HighPerformance Computing at the KTH Royal Institute of Technology (KTH-PDC), was to develop automatedprocedures for carrying out CFD analysis in the field of aerodynamic optimization and design. The project is asignificant step towards automation of the core processes that ordinarily would require specialist skills, such ascreation of the simulation mesh, thus assisting a broader sphere of engineers to design aircraft in more efficientand simpler ways.

The goal of aerodynamic design for airfoils and wings is to improve the performance of the lifting surfaces, e.g., by minimizing the drag. We consider here two approaches, the classical inverse design approach that finds the surface which produces desired pressure distributions, and the direct mathematical optimization based on local parameter searches, that is usually enabled by fast gradient computation, for example, by the adjoint method. The hybrid approach is to combine both of them. Each approach has its own pros and cons. In this chapter the approaches are assessed by application to the design of transonic RAE2822 airfoil and ONERA M6 wing.

The paper describes the comparative study of two optimization frameworks on Case III, twist optimization for induced-drag minimization. Both frameworks use gradient-based optimizers. With different flow solvers and other algorithmic differences they find different optimized shapes, all with the CD,i reduced by around 1 count.

The thesis develops computational tools for early stages of the aircraft design process. The work focuses on a framework which allows several design teams concurrently to develop a baseline concept into a configuration which meets requirements and whose aerodynamics has been assessed by flight simulation. To this end, a data base format suggested by the German Aerospace Center DLR was adopted in the CEASIOM system, developed in the EU 6th Framework Program, enabling more accurate transonic analysis and tabulation of forces and moments as well as control surface authority assessment. Results from simple, fast models are combined with computationally expensive full CFD results by co-Kriging to speed up productionof the aero-data for flight simulation.

Non-linear optimization methods in wing design play an increasingly important role together with computational aerodynamics. High performance computing enables the use of high-fidelity non-linear flow predictions in optimization loops. It is argued that the optimization tools should allow the engineer to influence the process by setting up suitable target pressure distributions for the shape to approach, combined with steps to minimize drag under suitable constraints on geometry, forces, and moments. The simulation framework incorporated into CEASIOM was applied to a number of configurations, conventional as well as un-conventional, such as an a-symmetric twin prop, a canard-configured transonic cruiser, and a novel chinrudder concept for transonic airliners. Aerodynamic shape design by the developed methods was applied to the standard M6 benchmark wing, a joined-wing concept, a wing-tip, and a blended wing-body.

Avhandlingen utvecklat beräkningsmoduler för tidiga stadier i flygplanskonstruktionsprocessen. Arbetet kocentreras på ett program-ramverk som låter flera designteam samtidigt utveckla en grund-modell till en konfiguration som uppfyller ställda krav och vars aerodynamik har undersökts med flygsimulering. För att nå detta mål antogs ett data-bas format utarbetat av DLR (German Aerospace Center) i CEASIOM-programpaketet som utvecklats i EUs sjätte ramprogram. Det möjliggjorde noggrannare analys och framtagning av tabeller över krafter och moment liksom bedömning av styrytors funktion i transoniskt fartområde. Resultat från enkla, snabba beräknngsmodeller kombineras via co-Kriging med beräkningsmässigt dyra CFD-körningar för att snabbt ta fram aero-data som behövs för flygsimuleringen.

Icke-linjär optimering spelar allt större roll i ving-formgivning, tillsammans med numerisk aerodynamik. Högpresterande datorer medger användning av noggranna icke-linjära strömningsmodeller också i optimerings-slingor. Det argumenteras för att optimerings-verktygen skall ge ingenjörerna direkt inflytande över processen genom definition av fördelaktiga tryckfördelningar som vingformen ska åstadkomma, kombinerat med steg som minimerar luftmotstånd under bivillkor på geometri, krafter och moment.

Simulerings-ramverket implementerat i CEASIOM tillämpas så på ett antal konfigurationer, konventionella såväl som o-konventionella: ett osymmetriskt tvåmotorigt propellerplan, och större transoniska flygplan, ett för Mach 0.97 med canardvinge, och ett nytt koncept med hak-roder.

Aerodynamisk formgivning med de utvecklade metoderna tillämpas på standardfallet M6-vingen, en transonisk dubbel-vinge, en vingtipp, och en flygande vinge.

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.

The aircraft design stages, conceptual and preliminary, are necessarily collaborative bytheir very nature. An example design carried out in this paper brings the collaborativeaspects of design to life by two academic groups, one in Naples and one in Stockholm, usingtheir own tools ADAS and CEASIOM, working respectively on conceptual and preliminarydesign. The ADAS tool is primarily empirically-based design methodology, and the CEA-SIOM tool is primarily physics-based design methodology. The example chosen is a FAR-23compliant 16-seat twin turboprop aircraft. The high-wing configuration resulting from theADAS conceptual design is the down-selected to CEASIOM where a water-tight model of thegeometry is constructed, a volume grid is generated and 16 flight conditions are simulatedby solutions of the Euler equations, some with propeller off, and others with propellerin order to judge the effect of the propeller wash over the main wing and horizontal tailsurface. Detailed comparisons between ADAS results and CEASIOM results for stability &control characteristics are carried out. In general there is reasonable agreement betweenthe two sets, considering that the empiricisms in ADAS account for viscous effects where asthe CEASIOM are purely inviscid (but nonlinear). The largest discrepancy appears in thepitching moment contribution from the horizontal tail, and various explanations for thisare suggested, including possible effects of the main wing downwash and wake on the tail.