How solution is initialized?

chintan · November 25, 2014, 17:42

Does SU2 initializes velocity to zero or it incorporates free stream conditions to initialize solution?

If not zero, is there a way to change that?

Sachchit · November 26, 2014, 03:50

Hi,

It will use free stream(farfield) conditions to initialize the solution. May I know why you would like to change it zero with non-zero freestream condition?

chintan · November 26, 2014, 12:23

Quote:

Originally Posted by Sachchit

Hi,

It will use free stream(farfield) conditions to initialize the solution. May I know why you would like to change it zero with non-zero freestream condition?

Hi Sachchit,
Thanks for reply.

I have two inlets and both have velocities in orthogonal direction Having initialization orthogonal to inlet velocity in one duct either slows down convergence or diverges. FMRES blew up and BICGSTAB takes roughly more than thrice the time per iteration compared to FMRES). This isn't desired as I have mesh with more than 11M cells.

Starting with zero velocity everywhere is best bet for my case. It would be great if someone could point me how to modify code. Thanks.

Sachchit · November 26, 2014, 13:01

Hi Chintan,

What you can do is set the farfield mach number to be 0. And then define both the inlet as velocity inlet and assign other patches to be pressure outlet except walls.

One other way which might be helpful is to develop the solution with only one inlet on and then after reaching steady state restart the solution with both the inlets on.

chintan · November 26, 2014, 13:09

Quote:

Originally Posted by Sachchit

Hi Chintan,

What you can do is set the farfield mach number to be 0. And then define both the inlet as velocity inlet and assign other patches to be pressure outlet except walls.

One other way which might be helpful is to develop the solution with only one inlet on and then after reaching steady state restart the solution with both the inlets on.

That's very helpful. Thanks a lot.

November 25, 2014, 17:42	How solution is initialized?	#1
chintan New Member Chintan Patel Join Date: Oct 2014 Location: USA Posts: 19 Rep Power: 11	Does SU2 initializes velocity to zero or it incorporates free stream conditions to initialize solution? If not zero, is there a way to change that?

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November 26, 2014, 03:50		#2
Sachchit New Member Sachchit Vekaria Join Date: Dec 2013 Posts: 18 Rep Power: 12	Hi, It will use free stream(farfield) conditions to initialize the solution. May I know why you would like to change it zero with non-zero freestream condition?

November 26, 2014, 13:01		#4
Sachchit New Member Sachchit Vekaria Join Date: Dec 2013 Posts: 18 Rep Power: 12	Hi Chintan, What you can do is set the farfield mach number to be 0. And then define both the inlet as velocity inlet and assign other patches to be pressure outlet except walls. One other way which might be helpful is to develop the solution with only one inlet on and then after reaching steady state restart the solution with both the inlets on.