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Acoustic receptivity simulations of flow past a flat plate with elliptic leading edge
KTH, Skolan för teknikvetenskap (SCI), Mekanik. KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW. KTH, Centra, SeRC - Swedish e-Science Research Centre.
KTH, Skolan för teknikvetenskap (SCI), Mekanik. KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW. KTH, Centra, SeRC - Swedish e-Science Research Centre. Swedish Defence Research Agency, Sweden.ORCID-id: 0000-0002-5913-5431
KTH, Skolan för teknikvetenskap (SCI), Mekanik. KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW. KTH, Centra, SeRC - Swedish e-Science Research Centre.ORCID-id: 0000-0001-7864-3071
2016 (engelsk)Inngår i: Journal of Fluid Mechanics, ISSN 0022-1120, E-ISSN 1469-7645, Vol. 800, artikkel-id R2Artikkel i tidsskrift (Fagfellevurdert) Published
Resurstyp
Text
Abstract [en]

We present results of numerical simulations of leading-edge acoustic receptivity for acoustic waves impinging on the leading edge of a finite-thickness flat plate. We use both compressible and incompressible flow solvers fitted with high-order high-accuracy numerical methods and independent methods of estimating the receptivity coefficient. The results show that the level of acoustic receptivity in the existing literature appears to be one order of magnitude too high. Our review of previous numerical simulations and experiments clearly identifies some contradictory trends. In the limit of an infinitely thin flat plate, our results are consistent with asymptotic theory and numerical simulations.

sted, utgiver, år, opplag, sider
Cambridge University Press, 2016. Vol. 800, artikkel-id R2
Emneord [en]
boundary layers, boundary layer receptivity, boundary layer stability
HSV kategori
Identifikatorer
URN: urn:nbn:se:kth:diva-190550DOI: 10.1017/jfm.2016.433ISI: 000379846600002Scopus ID: 2-s2.0-84978035402OAI: oai:DiVA.org:kth-190550DiVA, id: diva2:953431
Merknad

QC 20160817

Tilgjengelig fra: 2016-08-17 Laget: 2016-08-12 Sist oppdatert: 2017-11-28bibliografisk kontrollert
Inngår i avhandling
1. On stability and receptivity of boundary-layer flows
Åpne denne publikasjonen i ny fane eller vindu >>On stability and receptivity of boundary-layer flows
2016 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

This work is concerned with stability and receptivity analysis as well as studies on control of the laminar-turbulent transition in boundary-layer flows through direct numerical simulations. Various flow configurations are considered to address flow around straight and swept wings. The aim of this study is to contribute to a better understanding of stability characteristics and different means of transition control of such flows which are of great interest in aeronautical applications.

Acoustic receptivity of flow over a finite-thickness flat plate with elliptic leading edge is considered. The objective is to compute receptivity coefficient defined as the relative amplitude of acoustic disturbances and TS wave. The existing results in the literature for this flow case plot a scattered image and are inconclusive. We have approached this problem in both compressible and incompressible frameworks and used high-order numerical methods. Our results have shown that the generally-accepted level of acoustic receptivity coefficient for this flow case is one order of magnitude too high.

The continuous increase of computational power has enabled us to perform global stability analysis of three-dimensional boundary layers. A swept flat plate of FSC type boundary layer with surface roughness is considered. The aim is to determine the critical roughness height for which the flow becomes turbulent. Global stability characteristics of this flow have been addressed and sensitivity of such analysis to domain size and numerical parameters have been discussed.

The last flow configuration studied here is infinite swept-wing flow. Two numerical set ups are considered which conform to wind-tunnel experiments where passive control of crossflow instabilities is investigated. Robustness of distributed roughness elements in the presence of acoustic waves have been studied. Moreover, ring-type plasma actuators are employed as virtual roughness elements to delay laminar-turbulent transition.

sted, utgiver, år, opplag, sider
Stockholm: KTH Royal Institute of Technology, 2016. s. 49
Serie
TRITA-MEK, ISSN 0348-467X ; 2016:17
Emneord
boundary layer receptivity, acoustic receptivity, swept-wing flow, crossflow vortices, roughness element, global stability analysis, direct numerical simulation, plasma actuator
HSV kategori
Forskningsprogram
Teknisk mekanik
Identifikatorer
urn:nbn:se:kth:diva-196878 (URN)978-91-7729-184-8 (ISBN)
Disputas
2016-12-09, F3, Lindstedtsvägen 26, KTH, Stockholm, 10:15 (engelsk)
Opponent
Veileder
Merknad

QC 20161124

Tilgjengelig fra: 2016-11-24 Laget: 2016-11-24 Sist oppdatert: 2016-11-25bibliografisk kontrollert

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