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-   -   heat transfer probs by transonic flow (http://www.cfd-online.com/Forums/fluent/73924-heat-transfer-probs-transonic-flow.html)

Josh_Blue March 19, 2010 14:05

heat transfer probs by transonic flow
 
Hi all,

I am simulating the heat transfer between a sphere and its environment by subsonic and supersonic incident flow in 2D. Furthermore the flow shall be compressible.

Here some key data:
- sphere BC: wall, no slip and constant temperature
- inlet BC: pressure far field
- outlet BC: pressure outlet
- density based solver steady state

Now, I'm dealing some problems by simulating the transonic flow (0.8<M<1.4). Despite of good convergence (except of M=1.3 and M=1.4) the contour plot of velocity magnitude is really strange. The other ranges like 0.4<M<0.8 and M>1.4 meet my expectations both in convergence and contour plots.

So what am I doing wrong? Should I maybe run the simulation now unsteady or do I have to take sth. else into account??

Any suggestions and answers are welcome! Thanks in advance!! :-)

sega March 19, 2010 14:29

Turbulence?

Josh_Blue March 20, 2010 07:01

oh sorry, I forgot to mention: No, it's laminar...

sega March 20, 2010 09:22

Quote:

Originally Posted by Josh_Blue (Post 250902)
oh sorry, I forgot to mention: No, it's laminar...

I'm no expert, but can a transsonic flow be laminar?

Josh_Blue March 20, 2010 16:57

why not? I am not an expert as well, but I was thinking that there is no problem running a transonic and laminar simulation...

sega March 20, 2010 17:43

Quote:

Originally Posted by Josh_Blue (Post 250957)
why not? I am not an expert as well, but I was thinking that there is no problem running a transonic and laminar simulation...

Depends on your Reynolds number. Can you tell us what it is?

Josh_Blue March 20, 2010 18:11

well, since the sphere has a diameter of 5Ám, the Reynolds number is definitly below 100 (in between of 60 and 80)..

sega March 21, 2010 04:24

Ok, this is laminar. I have no further ideas, what may be wrong.
And your solution is good in medium and high Mach numbers?
Strange ...

Josh_Blue March 21, 2010 06:31

right, low and high Mach numbers are ok, but the transonic range... :-/


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