[chinna]

Hai, as i choosing coupled solver in solution method.. why there is no pseudo transient option for me..??

[Far]

pseudo transient option is available for coupled solver. Which version you are using?

[behest]

Hello Far,
I've used Ansys Fluent 14.5 and I want to apply Pseudo transient. Where is this option?
What is the diference between pseudo transient and transient?

Originally Posted by Far

pseudo transient option is available for coupled solver. Which version you are using?

[Far]

pseudo transient is an option in solution methods.

or go to solve > Methods...

[jamalf64]

Originally Posted by chinna

Hai, as i choosing coupled solver in solution method.. why there is no pseudo transient option for me..??

you should set your problem STEADY

[Marabelle]

Hello tehre!
I have a general question. I have to simulate a transient model. So far I just copied the settings of the precedent student working on that model. He enabled the "pseudo transient" option in the solution methods settings. What does the option "pseudo transient" mean resp. what does it cause/effect in the calculation?
Thanks so far, I would appreciate your answers!

[jamalf64]

Originally Posted by Marabelle

Hello tehre!
I have a general question. I have to simulate a transient model. So far I just copied the settings of the precedent student working on that model. He enabled the "pseudo transient" option in the solution methods settings. What does the option "pseudo transient" mean resp. what does it cause/effect in the calculation?
Thanks so far, I would appreciate your answers!

pseudo transient adds a term to equations(i.e d/dt=constant and not zero). This leads to a better convergence

[Far]

It is like solving the problem with high gradient and initially unstable solution (and ultimately steady state and stable solution) with unsteady solver and choosing bigger time step. In this way the initial transients (non-physical) will wash away and you will get a very nice convergence.

[duri]

Pseudo transient solves the unsteady equation with time stepping calculated from large scale domain information rather local cell information. And same time step is applied to all cells exactly like global time stepping. The main advantage is that convergence acceleration occurs in regions of mesh induced stiffness. (like boundary layer)

[Tanjina]

Hello everyone.

For my 3D unsaturated porous media model, I am using VOF. Water level will change with time and after some time it will become steady. So initially it is unsteady. For saving time, I used steady time step with pseudo transient option. Water level was falling perfectly, after some time it became steady also.

I just want to make myself sure that for unsteady model like this, I can use steady time with pseudo transient option. I was going through the literature available for pseudo-transient time step, but I kinda lost. Then I found this thread.

Could anyone please help me in this regard?

Thanks in advance.

Regards,
Tanjina