Noise level effect on the hypersonic boundary layer

Abstract

The boundary layer state has a critical effect on hypersonic vehicle performance and the noise level is the main factor causing the differences between the boundary layer transition in a wind tunnel test and that in a real flight. The second mode wave frequency of the 7° half-angle cone models as measured in four hypersonic wind tunnels is collected. The effects of the noise level on the boundary layer are determined by comparing dimensionless parameters, which are nondimensionalized based on computed values. The results indicate that the noise level could affect the second mode wave frequency and the boundary layer thickness, where the second mode wave frequency decreases and the boundary layer thickness increases with increasing noise level. However, the mechanism by which the noise level influences the second mode wave frequency and the boundary layer thickness requires further study.