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-   -   Unable to Initialising to M=1.71 (http://www.cfd-online.com/Forums/fluent/46022-unable-initialising-m-1-71-a.html)

ravi September 13, 2007 03:25

Unable to Initialising to M=1.71
 
I am trying to solve a supersonic flow of M=1.71 (472 m/s)over a cavity in side a test-section. I gave the inlet as pressure inlet and outlet as pressure outlet. I calculated the static pressure and temperature exactly. In MATERAILS i selected ideal-gas and sutherland formula.

But when i m tryin to initialise at the inlet, the velocity is 392 m/s only i.e M=1.4. that means i m not able to get M=1.71 at the inlet, whicih i specified in boundary conditions. where m i goin wrong. can somebdy help me pls...

thanks ravi

raj September 14, 2007 02:04

Re: Unable to Initialising to M=1.71
 
hi!

initialisation takes average value all over the grid(or by some other means), it need not necessarily take the 1.71 at inlet, as the solution converges, the b.c's will get satisfied. its the iteration procedure, which takes rough values at the start and refine them through the iterations.

regards, raj.

rav_aero September 14, 2007 02:37

Re: Unable to Initialising to M=1.71
 
no with iterations the M value didnt change. I have checked, even after 26,000 itterations the value is still 1.4 only.


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