Pseudo Transient approach

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 January 28, 2005, 03:09 Pseudo Transient approach #1 Xobile Guest   Posts: n/a 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,

 January 28, 2005, 18:34 Re: Pseudo Transient approach #2 Piet Guest   Posts: n/a 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

 January 29, 2005, 00:41 Re: Pseudo Transient approach #3 Xobile Guest   Posts: n/a 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??

 January 29, 2005, 04:13 Re: Pseudo Transient approach #4 sankar Guest   Posts: n/a try reducing residual tolerance for primary variables to avoid this problem

 January 29, 2005, 15:39 Re: Pseudo Transient approach #5 Piet Guest   Posts: n/a 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

 February 3, 2013, 06:03 #6 New Member   Join Date: Dec 2011 Posts: 29 Rep Power: 7 What is the difference between pseudo transient simulation and transient simulation?

 May 18, 2013, 14:22 #7 Super Moderator   Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,329 Blog Entries: 6 Rep Power: 45 Transient simulation is to solve the problem in time-accurate fashion, while pseudo transient is method to get the steady state solution

June 30, 2014, 05:19
#8
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Ke Wu
Join Date: Jan 2012
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Quote:
 Originally Posted by Far 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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