Numerical modelling of supersonic boundary-layer receptivity to solid particulates

Abstract

Atmospheric particulates may be a major source of boundary-layer instabilities leading to laminar–turbulent transition on aerodynamically smooth bodies flying at supersonic speeds. Particulates penetrating into the boundary-layer flow can excite wavepackets of the first- and/or second-mode instability. The packets grow downstream, reach the threshold amplitude and ultimately break down to turbulent spots. A numerical model is developed to simulate excitation of unstable wavepackets by spherical solid particulates. As an example, computations are carried out for a $14^{\circ }$ half-angle sharp wedge flying at an altitude of 20 km, Mach number 4 and zero angle of attack. The numerical results agree satisfactorily with the theory developed by Fedorov (J. Fluid Mech., vol. 737, 2013, pp. 105–131). The numerical model opens up an opportunity to investigate receptivity to particulates for practical supersonic and hypersonic configurations such as blunt bodies of revolution.