Direct Numerical Simulations of Supersonic Boundary Layer Receptivity to Acoustic Disturbances

2005 ◽  
Author(s):  
I. Egorov ◽  
A. Fedorov ◽  
V. Soudakov
Keyword(s):  
Boundary Layer ◽  
Numerical Simulations ◽  
Supersonic Boundary Layer ◽  
Direct Numerical Simulations ◽  
Acoustic Disturbances

scholarly journals Control of laminar breakdown in a supersonic boundary layer employing streaks

2021 ◽  
Vol 932 ◽  
Author(s):  
Simon Kneer ◽  
Zhengfei Guo ◽  
Markus J. Kloker
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Laminar Flow ◽  
Point Source ◽  
Numerical Simulations ◽  
Supersonic Boundary Layer ◽  
Direct Numerical Simulations ◽  
Roughness Elements ◽  
Controlling Mechanism ◽  
Laminar Flow Control

In this study direct numerical simulations are employed to investigate the effects of various parameters on the laminar-flow-control capabilities of narrowly spaced streaks in a supersonic boundary layer at Mach $2.0$ . Previous work by Sharma et al. (J. Fluid Mech., vol. 873, 2019, pp. 1072–1089) has found these streak modes, excited by a spanwise blowing-and-suction strip, to be highly effective at delaying pure oblique-type breakdown. In the present work it is shown that spectrum-enriching subharmonic modes, relevant with increasing running-length Reynolds number, do not destroy the controlling mechanism, and also a complex breakdown scenario, triggered by a multi-frequency point source, is found to be effectively controlled. Moreover, the control-streak excitation by roughness elements is compared in detail with the blowing-and-suction method, revealing relevant differing features.

Sensitivity of a supersonic boundary layer to acoustic disturbances

1992 ◽  
Vol 27 (1) ◽  
pp. 29-34 ◽  
Author(s):  
A. V. Fedorov ◽  
A. P. Khokhlov
Keyword(s):  
Boundary Layer ◽  
Supersonic Boundary Layer ◽  
Acoustic Disturbances

Direct Numerical Simulations of Transitional Separation–Bubble Development in Swept–Blade Flow Conditions

2012 ◽  
Author(s):  
Joshua R. Brinkerhoff ◽  
Metin I. Yaras
Keyword(s):  
Boundary Layer ◽  
Numerical Simulations ◽  
Shear Layer ◽  
Pressure Field ◽  
Separation Bubble ◽  
Three Dimensional ◽  
Direct Numerical Simulations ◽  
Small Scale ◽  
Flow Conditions ◽  
Crossflow Instability

This paper describes numerical simulations of the instability mechanisms in a separation bubble subjected to a three-dimensional freestream pressure distribution. Two direct numerical simulations are performed of a separation bubble with laminar separation and turbulent reattachment under low freestream turbulence at flow Reynolds numbers and streamwise pressure distributions that approximate the conditions encountered on the suction side of typical low-pressure gas-turbine blades with blade sweep angles of 0° and 45°. The three-dimensional pressure field in the swept configuration produces a crossflow-velocity component in the laminar boundary layer upstream of the separation point that is unstable to a crossflow instability mode. The simulation results show that crossflow instability does not play a role in the development of the boundary layer upstream of separation. An increase in the amplification rate and most amplified disturbance frequency is observed in the separated-flow region of the swept configuration, and is attributed to boundary-layer conditions at the point of separation that are modified by the spanwise pressure gradient. This results in a slight upstream movement of the location where the shear layer breaks down to small-scale turbulence and modifies the turbulent mixing of the separated shear layer to yield a downstream shift in the time-averaged reattachment location. The results demonstrate that although crossflow instability does not appear to have a noticeable effect on the development of the transitional separation bubble, the 3D pressure field does indirectly alter the separation-bubble development by modifying the flow conditions at separation.

Sign in / Sign up

Export Citation Format

Share Document