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oe September 3, 2008 16:28

Grid generation and Compressible Euler equations
 
When generating grids for a supersonic jet impingement flow, and solving the compressible Eulers equations should y+ value be considered, in placing the first grid point from the wall.

Thanks a lot


Charles September 4, 2008 02:57

Re: Grid generation and Compressible Euler equatio
 
y+ is a dimensionless boundary layer characteristic. If you have a boundary layer with Euler equations you have a problem.

shuo September 7, 2008 03:48

Re: Grid generation and Compressible Euler equatio
 
Hi oe,

I am also working on supersonic impinging jets for my PhD. Should get in touch.

Shuo

oe September 8, 2008 11:51

Re: Grid generation and Compressible Euler equatio
 
Hi Charles, Thanks for the reply Charles and Shuo. I am interested in studying the unsteady pressure signature on the plate. And my understanding is that a stagnation region is created where the jet impinges on the plate (this is where y+ value would be important). Beyond this region the flow again continues to be sonic/supersonic. Obviously all this depending on the distance of the plate the from the jet exit and the pressure ratio. Since the interest is in unsteady pressure signature how important is the y+ in grid generation? Or can I ask what should be the criteria for grid generation when solving compressible Euler equations?

Shuo what aspect of supersonic impinging jet are you looking at? it would be good to interact.

Thanks again.


Ahmed September 8, 2008 14:41

Re: Grid generation and Compressible Euler equatio
 
(this is where y+ value would be important) How would you calculate that y+ in a Zero kinematic viscocity fluid? you are solving Euler's equations, right Am I missing something here Is it the same Euler's equations I studied more than twenty years ago or what?

oe September 8, 2008 15:28

Re: Grid generation and Compressible Euler equatio
 
Yes I am solving for Compressible Euler's equations. You are right about the zero kinematic viscosity. My question is where should the first grid point be placed (distance from the wall). Is there any criteria for that?

Thanks


Shuo September 8, 2008 21:02

Re: Grid generation and Compressible Euler equatio
 
Hi oe

SInce your solving Euler equations, there shouldn't be a boundary layer/wall jet along the plate. My email address is Shuo.Li@eng.monash.edu.au if you want to discuss it more.

Shuo

Ahmed September 8, 2008 21:28

Re: Grid generation and Compressible Euler equatio
 
I am not aware of such rule, and would appreciate if you find something to the respect that you put it to my attention. You have to look for error estimation and reduce the size of your mesh accordingly, Good luck in your research.


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