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Shuo October 11, 2007 21:11

supersonic flows
 
What type of supersonic flows can be modelled accurately using Euler equations other than supersonic jets? Are there experimental data available for these flow?

Cheers, Shuo

pc October 12, 2007 09:17

Re: supersonic flows
 
First of all, you shouldn't use the Euler equations for jets because most jets are turbulent.

Second, the Euler equations are appropriate for any supersonic flow where viscous effects are negligible.

Third, available experimental data will depend on what class of problem you're looking for.

shuo October 12, 2007 19:30

Re: supersonic flows
 
I read that Euler equations are OK for supersonic jets. I am modelling gas-particle supersonic impinging jets.


pc October 12, 2007 20:57

Re: supersonic flows
 
If your particles are large enough that they are not affected by the gas phase, an Euler assumption may be sufficient. However if the particles are smaller, by neglecting turbulence, your calculations will omit the radial spread of the particles due to turbulent interactions. Particle trajectories are known to be affected (dispersed) by turbulent eddies.

shuo October 12, 2007 21:17

Re: supersonic flows
 
What is the definition of 'small' particles. The particles in the flow i am looking at will be of the order 1-50 micrometers. Is there a reference for the turbulence comment?

Shuo

pc October 12, 2007 22:53

Re: supersonic flows
 
It depends on the particle density, but I would say anything below 20 microns will definitely be subject to dispersion by turbulence. There are numerous papers in the literature on turbulent dispersion of particles in shear layers and jets, but most papers I know of are at low speeds. Look up Stochastic Separated Flow (SSF) models.

Good luck.



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