Stabilization of Hypersonic Boundary Layers by Porous Coatings

A second-mode stability analysis has been performed for a hypersonic boundary layer on a wall covered by a porous coating with equally spaced cylindrical blind microholes. Massive reduction of the second mode amplification is found to be due to the disturbance energy absorption by the porous layer. This stabilization effect was demonstrated by experiments recently conducted on a sharp cone in the T-5 high-enthalpy wind tunnel of the Graduate Aeronautical Laboratories of the California Institute of Technology. Their experimental confirmation of the theoretical predictions underscores the possibility that ultrasonically absorptive porous coatings may be exploited for passive laminar flow control on hypersonic vehicle surfaces.

[1]  J. M. Kendall.  Wind Tunnel Experiments Relating to Supersonic and Hypersonic Boundary-Layer Transition , 1974 .

[2]  Kenneth F. Stetson,et al.  Laminar boundary layer stability experiments on a cone at Mach 8. I - Sharp cone , 1983 .

[3]  E. Reshotko.  Boundary layer instability, transition and control , 1994 .

[4]  Stability of the Inviscid Shock Layer in Strong Interaction Flow Over a Hypersonic Flat Plate , 1993 .

[5]  A. Fedorov,et al.  Experiments on passive hypervelocity boundary layer control using a porous surface , 2001 .

[6]  J. Cole,et al.  Problems in high speed flow prediction relevant to control , 1998 .

[7]  A. Fedorov,et al.  Stabilization of a hypersonic boundary layer by ultrasound-absorbing coatings , 2002 .

[8]  Yvan Champoux,et al.  Propagation of sound and the assignment of shape factors in model porous materials having simple pore geometries , 1992 .

[9]  M. Malik.  Prediction and control of transition in supersonic and hypersonic boundary layers , 1989 .

[10]  R. Kimmel,et al.  Space-time correlation measurements in a hypersonic transitional boundary layer , 1995 .

[11]  R. Kimmel,et al.  On the breakdown of a hypersonic laminar boundary layer , 1993 .

[12]  D. M. Bushnell,et al.  Boundary layer transition in hypersonic flows , 1990 .

[13]  D. Capriotti,et al.  Viscous optimized hypersonic waveriders , 1987 .

[14]  A. Demetriades,et al.  Hypersonic viscous flow over a slender cone. III - Laminar instability and transition , 1974 .

[15]  R. Kimmel,et al.  Drag Prediction and Transition in Hypersonic Flow , 1997 .

[16]  F. B. Daniels.  On the Propagation of Sound Waves in a Cylindrical Conduit , 1950 .

[17]  Hans G. Hornung,et al.  Experiments on passive hypervelocity boundary-layer control using an ultrasonically absorptive surface , 2002 .

[18]  J. Kendall.  Wind Tunnel Experiments Relating to Supersonic and Hypersonic Boundary-Layer Transition , 1974 .

[19]  Eli Reshotko,et al.  Stability theory as a guide to the evaluation of transition data. , 1969 .