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Pseudo Transient approach

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Old   January 28, 2005, 03:09
Default Pseudo Transient approach
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Xobile
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Hello,

does anyone have any tutorial or simulation which uses pseudo transient approach as an initial guess for flow field initialization?

I am running a high speed compressible flow and would really appreciate any help,
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Old   January 28, 2005, 18:34
Default Re: Pseudo Transient approach
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Piet
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A tutorial what for? Just switch it on, set your time step (in your case 1.E-08) and run it! There's nothing special that could be mentioned in a tutorial!!!

hope this helps

Piet
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Old   January 29, 2005, 00:41
Default Re: Pseudo Transient approach
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Xobile
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when i am running steady state option for high speed compressible flow... it is giving me a converged solution.

But when i run the same case for pseudo-transient case, the simulation stops due to negative densities in more than 100 cells.. of course my time step was 0.1

will decreasing my time step to 1E-8 solve this issue??

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Old   January 29, 2005, 04:13
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sankar
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try reducing residual tolerance for primary variables to avoid this problem
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Old   January 29, 2005, 15:39
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Piet
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Yes, your are absolutely right. It can solve your problem. Maybe 1.E-8 is not small enough! Try to lower it further for several hundred steps and enhance it from time to time. Any hint for such cases is to start the calculation with a dependency of temperature. This means rho = f(T) and switch back after lets say 100 iterations.

best regards

Piet
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Old   February 3, 2013, 06:03
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What is the difference between pseudo transient simulation and transient simulation?
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Old   May 18, 2013, 14:22
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Transient simulation is to solve the problem in time-accurate fashion, while pseudo transient is method to get the steady state solution
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Old   June 30, 2014, 05:19
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Quote:
Originally Posted by Far View Post
Transient simulation is to solve the problem in time-accurate fashion, while pseudo transient is method to get the steady state solution
Hi

In what problems, we are recommended to apply pseudo transient method?

Thanks
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