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Jianfeng Zou October 24, 2007 06:59

absolute pressure limit
 
Dear everyone. I run a 3D case with fluent. After 100+ iterations, the solver present 'absolute pressure limited to 1.0 in xx cells on zone xx'. Ideal gas was used. How should I do? Should I refine my grid system. If the computation continues, a resonable solution will be achieved finally?


AJK October 24, 2007 12:13

Re: absolute pressure limit
 
let the simulation run for a while and this error may go away or else you need to make ur mesh fine in that particular area or use grid adaption technique

Venkatesh V October 24, 2007 19:13

Re: absolute pressure limit
 
If you are running transient problem reduce the time step. If you are running steady state reduce the under relaxation factors.

I think currently your Min absolute pressure 1. I would suggest you set that to reasonable valve. I would suggest you to set resonable limits for all the values.

Thanks Venkatesh V

Jianfeng Zou October 24, 2007 21:02

Re: absolute pressure limit
 
Dear AJK and Venkatcsh V, I am simulating a turbulence diffusion hydrogen flame(the incoming air is supersonic and the fuel is sonic). I found the low pressure (about the pressure limit 1.0 Pa) locate mainly in the near region around the hydrogen jet. Besides mesh finement, using small time step size, etc, what else should I do to the boundary condition or initial condition?

Bye the way, after 100+ iterations with pressure limit warning, my calculation seem to be steady, anyway.

goldenland October 25, 2007 02:56

Re: absolute pressure limit
 
When I simulate the supersonic gas flow in the nozzle, I met the same problem. In this case, I change the limitation value of the absolute pressure(solve->control->limits...->absolute pressure) to a very small value.

In my case, the problem is solved. So you can try yours.

Good luck.


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