Standing waves in exhaust gases

[Jay-qu]

Upon watching the following clip, I am left wondering how the hell those standing waves (see pic) are created in the exhaust and if they have some practical function..

YouTube - Nasa Methane Rocket Test - Impressive

J

[Moontanman]

Originally Posted by Jay-qu

Upon watching the following clip, I am left wondering how the hell those standing waves (see pic) are created in the exhaust and if they have some practical function..

YouTube - Nasa Methane Rocket Test - Impressive

J

I'm not sure if this has any relation to the waves you are showing but In a two stroke engine the exhaust, called an expansion chamber, uses the shape of the chamber to guide sound waves to scavenge the cylinder on each stroke. These sound waves cause a partial vacuum at the exhaust port. Could this be a similar phenomenon caused by the shape of the exhaust chamber?

[Turtle]

Originally Posted by Jay-qu

Upon watching the following clip, I am left wondering how the hell those standing waves (see pic) are created in the exhaust and if they have some practical function..

J

Found this for you J. Exhaust Gases' Diamond Pattern - Level 3

[Jay-qu]

Thanks Turtle thats perfect