Spatial evolution of nonlinear acoustic mode instabilities on hypersonic boundary layers
Abstract
The effects are considered of strong critical layer nonlinearity on the spatial evolution of an initially linear acoustic mode instability wave on a hypersonic flat plate boundary layer. The analysis shows that nonlinearity, which is initially confined to a thin critical layer, first becomes important when the amplitude of the pressure fluctuations become 0(1/M exp 4 In M exp 2), where M is the free stream Mach number. The flow outside the critical layer is still determined by linear dynamics and therefore takes the form of a linear instability wave, but with its amplitude completely determined by the flow within the critical layer. The latter flow is determined by a coupled set of nonlinear equations, which were solved numerically.
 Publication:

NASA STI/Recon Technical Report N
 Pub Date:
 December 1989
 Bibcode:
 1989STIN...9014517G
 Keywords:

 Acoustic Instability;
 Boundary Layer Flow;
 Boundary Layer Stability;
 Flow Distribution;
 Hypersonic Flow;
 Spatial Distribution;
 Flat Plates;
 Free Flow;
 Mach Number;
 Nonlinear Equations;
 Pressure Effects;
 Wave Propagation;
 Fluid Mechanics and Heat Transfer