Add a Media Piece
default edit
Back to the Gallery

Title: Axially collapsing instability mode

Description: Shadowgraph images captured at 1,000,000 frames per second show an underexpanded impinging jet of air with a nozzle pressure ratio (nozzle stagnation pressure divided by ambient pressure) of NPR=3.5, and a non-dimensional impingement distance of Z/D=3 (Where Z is the impingement distance and D is the nozzle diameter). At this ratio the jet is influenced by a an axially collapsing instability mode which causes second, third and fourth normal shockwaves to collapse on top of one another. This mode is accompanied by an extremely loud, discrete tone.

Credits: Adam Risborg - Laboratory for Turbulence Research in Aerospace and Combustion, Department of Aerospace and Mechanical Engineering, Monash University

References: See 'adamrisborg' Youtube page for updated list of references

Web Page:

Contributed By: Adam Risborg

The eFluids editor for videos is G. M. "Bud" Homsy (
and for images is Jean Hertzberg (
Please contact them if you have any problems, questions, or concerns related to the galley or videos and images.
© Copyright on the videos is held by the contributors.
Apart from Fair Use, permission must be sought for any other purpose.