Laminar-turbulent transition caused by modal disturbance growth in the wake flow of isolated roughness elements on blunt re-entry capsules is studied numerically at typical cold hypersonic wind-tunnel conditions. Two fundamentally different heat shield shapes are considered. On the sphere-cone forebody the wake flow of the roughness is exposed to an adverse pressure gradient, whereas the spherical heat shield exhibits a strongly favorable pressure gradient. The pressure gradient effects on the development of the stationary wake flow and its modal instability characteristics are discussed for various heights and diameters of the cylindrical roughness element. Regions of increased shear develop in its wake, which persist longer in the adverse pressure gradient case. Consequently, the results of spatial two-dimensional eigenvalue analyses reveal that the unstable wake-flow region extends much further downstream and the wake-mode instabilities are considerably more amplified. The disturbance kinetic energy production terms are used to assess the contributions of the different shear-layer regions to the mode growth and its dependence on the pressure gradient.
Theiss A, Ali SR, Hein S, et al. Numerical and experimental investigation of laminar-turbulent boundary layer transition on a blunt generic re-entry capsule. Paper 2014-2353, AIAA.
2.
Chang CL, Choudhari M, Hollis B, et al. Transition analysis for the Mars Science Laboratory entry vehicle. Paper 2009-4076, AIAA.
3.
Theiss A, Lichtmes M and Hein S. Local stability analysis of laminar-turbulent boundary layer transition on blunt generic re-entry capsules. In: Notes on numerical fluid mechanics and multidisciplinary design. Basel: Springer International Publishing, 2016, pp.279–288.
4.
LiFChoudhariMChangCL, et al.Effects of injection on the instability of boundary layers over hypersonic configurations. Phys Fluids2013; 25: 104107–104107.
5.
Grossir G, Paris S and Chazot O. Evaluation of the effects of distributed roughness induced transition on the EXPERT vehicle. In: International Planetary Probe Workshop 2010 (IPPW-7).
6.
Hollis BR. Distributed roughness effects on blunt-body transition and turbulent heating. Paper 2014-0238, AIAA.
7.
Leidy AN, Reshotko E, Siddiqui F, et al. Characterizing the transient growth mechanism on a hypersonic blunt body at a high angle of attack. Paper 2016-3951, AIAA.
8.
RedaDC. Review and synthesis of roughness-dominated transition correlations for reentry applications. J Spacecr Rockets2002; 39: 161–167.
9.
RedaDCWilderMCPrabhuDK. Transition experiments on blunt bodies with isolated roughness elements in hypersonic flight. J Spacecr Rockets2010; 47: 828–835.
10.
Amar A, Horvath T, Hollis B, et al. Protuberance boundary layer transition for project Orion Crew Entry Vehicle. Paper 2008-1227, AIAA.
11.
BergerKT. Aerothermodynamic testing of the Crew Exploration Vehicle at Mach 6 and Mach 10. J Spacecr Rockets2009; 46: 758–765.
12.
Tanno H, Komuro T, Sato K, et al. Aeroheating measurement of Apollo shaped capsule with boundary layer trip in the free-piston shock tunnel HIEST. Paper 2014-0434, AIAA.
13.
Marineau E, Laurence S and Hornung H. Apollo-shaped capsule boundary layer transition at high-enthalpy in T5. Paper 2010-446, AIAA.
14.
Chang CL, Choudhari M, Venkatachari BS, et al. Effects of cavities and protuberances on transition over hypersonic vehicles. Paper 2011-3245, AIAA.
15.
SchneiderSP. Summary of hypersonic boundary-layer transition experiments on blunt bodies with roughness. J Spacecr Rockets2008; 45: 1090–1105.
16.
Kegerise MA, King RA, Choudhari M, et al. An experimental study of roughness-induced instabilities in a supersonic boundary layer. Paper 2014-2501, AIAA.
17.
WheatonBMSchneiderSP. Hypersonic boundary-layer instabilities due to near-critical roughness. J Spacecr Rockets2014; 51: 327–342.
18.
De TullioNParedesPSandhamND, et al.Laminar–turbulent transition induced by a discrete roughness element in a supersonic boundary layer. J Fluid Mech2013; 735: 613–646.
19.
Marxen O, Iaccarino G and Shaqfeh E. Numerical simulations of hypersonic boundary-layer instability with localized roughness. Paper 2011-567, AIAA.
20.
IyerPSMaheshK. High-speed boundary-layer transition induced by a discrete roughness element. J Fluid Mech2013; 729: 524–562.
21.
BernardiniMPirozzoliSOrlandiP, et al.Parameterization of boundary-layer transition induced by isolated roughness elements. AIAA J2014; 52: 2261–2269.
22.
Van den EyndeJPJPSandhamND. Numerical simulations of transition due to isolated roughness elements at Mach 6. AIAA J2016; 54: 53–65.
23.
LoiseauJCRobinetJCCherubiniS, et al.Investigation of the roughness-induced transition: global stability analyses and direct numerical simulations. J Fluid Mech2014; 760: 175–211.
24.
GroskopfGKlokerMJ. Instability and transition mechanisms induced by skewed roughness elements in a high-speed laminar boundary layer. J Fluid Mech2016; 805: 262–302.
25.
Choudhari M, Li F, Chang CL, et al. Laminar-turbulent transition behind discrete roughness elements in a high-speed boundary layer. Paper 2010-1575, AIAA.
26.
Choudhari M, Li F, Bynum MD, et al. Computations of disturbance amplification behind isolated roughness elements and comparison with measurements. Paper 2015-2625, AIAA.
27.
Theiss A and Hein S. Investigation on the wake flow instability behind isolated roughness elements on the forebody of a blunt generic reentry capsule. In: Knight D, Bondar Y, Lipatov I, et al. (eds) Progress in flight physics, vol. 9. Les Ulis: EDP Sciences, pp.451–480.
28.
Theiss A, Hein S, Ali SRC, et al. Wake flow instability studies behind discrete roughness elements on a generic re-entry capsule. Paper 2016-4382, AIAA.
29.
PlogmannBWürzWKrämerE. On the disturbance evolution downstream of a cylindrical roughness element. J Fluid Mech2014; 758: 238–286.
30.
Ali SRC, Radespiel R and Theiss A. Transition experiment with a blunt Apollo shape like capsule in hypersonic Ludwieg tube. 63. Deutscher Luft- und Raumfahrtkongress 2014, Paper 2014-340270.
31.
Hollis B, Liechty D, Wright M, et al. Transition onset and turbulent heating measurements for the Mars Science Laboratory entry vehicle. Paper 2005–1437, AIAA.
32.
Raddatz J and Fassbender JK. Block structured Navier–Stokes solver FLOWer. In: Kroll N and Fassbender JK (eds) MEGAFLOW – numerical flow simulation for aircraft design. Berlin/Heidelberg: Springer, 2005, pp.27–44.
33.
Lichtmes M. Numerische Untersuchung zur Grenzschichtstabilität an der Atmosphäreneintrittskapsel des Mars Science Laboratory im hypersonischen Strömungsfeld. Master’s Thesis, Hochschule Trier – Umwelt-Campus Birkenfeld, Trier, 2015.
34.
Leyh S. Numerische Stabilitätsuntersuchung des Nachlaufs einer diskreten Rauigkeit auf einer Wiedereintrittskapsel. Master’s Thesis, Technische Universität Berlin, Berlin, 2017.
35.
BridgesTMorrisP. Differential eigenvalue problems in which the parameter appears nonlinearly. J Comput Phys1984; 55: 437–460.
36.
HermannsMHernándezJA. Stable high-order finite-difference methods based on non-uniform grid point distributions. Int J Numer Methods Fluids2007; 56: 233–255.
37.
LandahlMT. On sublayer streaks. J Fluid Mech1990; 212: 593–614.
38.
AnderssonPBrandtLBottaroA, et al.On the breakdown of boundary layer streaks. J Fluid Mech2001; 428: 29–60.
39.
Choudhari M, Norris A, Li F, et al. Wake instabilities behind discrete roughness elements in high speed boundary layers. Paper 2013-81, AIAA.
40.
BrandtL. Numerical studies of the instability and breakdown of a boundary-layer low-speed streak. Eur J Mech B Fluids2007; 26: 64–82.
