Nonlinear behaviour of the Mack mode in a hypersonic boundary layer

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

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


Mack-mode waves are measured in a hypersonic boundary layer using high-frequency focusing schlieren deflectometry. Experiments are performed using a flared cone at angle of attack in the low-disturbance Mach 6 Quiet Tunnel at Texas A&M University across a free-stream unit Reynolds number range of. 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. 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.

Original languageEnglish (US)
Pages (from-to)74-99
Number of pages26
JournalJournal of Fluid Mechanics
StatePublished - Aug 10 2019


  • boundary layer stability
  • high-speed flow
  • nonlinear instability

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering
  • Applied Mathematics


Dive into the research topics of 'Nonlinear behaviour of the Mack mode in a hypersonic boundary layer'. Together they form a unique fingerprint.

Cite this