Nonlinear behaviour of the Mack mode in a hypersonic boundary layer Academic Article uri icon


  • Mack-mode waves are measured in a hypersonic boundary layer using high-frequency focusing schlieren deflectometry. Experiments are performed using a $5^{circ }$ flared cone at $0^{circ }$ angle of attack in the low-disturbance Mach6 Quiet Tunnel at Texas A&M University across a free-stream unit Reynolds number range of $7.8 imes 10^{6}~ ext{m}^{-1}leqslant mathit{Re}^{prime }leqslant 11.0 imes 10^{6}~ ext{m}^{-1}$. The high-frequency response of the measurement system allows harmonics and other nonlinear behaviour to be measured. Mack-mode waves and several harmonics are clearly observed at a frequency of $f_{0}approx 250~ ext{kHz}$. Bispectral analysis is used to show that these waves undergo several quadratic phase-coupled sum and difference interactions with themselves to produce harmonics, as well interact with a relatively low-frequency wave that results in amplitude modulation. Bispectral analysis is used to highlight these interactions.

published proceedings


altmetric score

  • 0.25

author list (cited authors)

  • Craig, S. A., Humble, R. A., Hofferth, J. W., & Saric, W. S.

citation count

  • 34

complete list of authors

  • Craig, Stuart A||Humble, Raymond A||Hofferth, Jerrod W||Saric, William S

publication date

  • August 2019