Boundary Conditions for gun barrel muzzle blast

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  • Last Post 29 July 2018
Mr_fixit16 posted this 27 July 2018

Hi everyone, I am attempting to perform a rough simulation of a gun barrel muzzle blast. I am using density based, transient, viscous k-e model with standard wall function, energy equation on, initially carbon monoxide for gas in the barrel, initially air for gas outside the barrel.

I appear to have trouble with the boundary conditions. The flow appears to be progressing well, until the shock wave hits the edge of my model.

before boundary interaction

during boundary interaction

after boundary interaction

The only solution i can see would be to simply increase the domain size, but by doing so the 500k cell limit for the student version is exceeded quite easily.

I am using a pressure outlet boundary specification. I considered the pressure far field condition, but after reading about it, it appears it may not be best suited for this problem.boundary specification

Does anyone have any suggestions? I'm open to any recommendations.

Thanks!

abenhadj posted this 29 July 2018

You can make a use of General NRBC with some extension of the model. The extension does not need to be high resolved. A coarse grid would help diffuse out the wave. General NRBC would help avoiding false reflection.

Best regards,

Amine

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