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-   -   Flow Through an Immersed Solid ! (http://www.cfd-online.com/Forums/cfx/92417-flow-through-immersed-solid.html)

 kimiaghalam September 13, 2011 23:18

Flow Through an Immersed Solid !

I am using the immersed solid to model a valve. When the valve is closed I expect it stop the flow of water behind it but when I check the stream lines and the velocity contour it seems like the flow is passing through the valve. What do you think is wrong with my model ?

 ghorrocks September 14, 2011 05:49

The immersed solid approach uses a factor to slow the flow, I can't remember its name. Have you set this factor high enough?

 stumpy September 14, 2011 09:27

It's "Momentum Source Scaling Factor". Try a value of 100, and also set the expert parameter "smooth inside ims = t" to improve convergence when a high scaling factor is used. You'll have to type that parameter in the command editor since it's not in the GUI.

Having said this I have found "leakage" occurs when trying to block the flow using an immersed solid. The problem is that the solver applies a scaling factor, but when the velocity is zero the scaling factor doesn't do much. I guess just see how high you can make the scaling factor before convergence becomes too difficult.

 belgacem May 25, 2012 06:05

Hi Friends
I am also studying immersed boundary method and and try to simulate a block falling in the water. I am using "immersed solid" then rigid body 6DOF and I let it fall freely but it can't stoped in the bottom where the velocity must be zero. I give a density to the block and i let it fall freely under gravity. Noted that the rigid body is defined as an immersed solid. i have specified a stationary coordinate frame that has its origin at the center of mass of the physical rigid body. Another fixed coordinate frame was specified related to the water at rest.
What can I do to stopped the rigid body in the bottom where the potentiel energy must be zero?

thank you!

 yuanmengyuan1989 April 7, 2013 04:56

if i did as you said,i occoured an error!why?

Quote:
 Originally Posted by stumpy (Post 324105) It's "Momentum Source Scaling Factor". Try a value of 100, and also set the expert parameter "smooth inside ims = t" to improve convergence when a high scaling factor is used. You'll have to type that parameter in the command editor since it's not in the GUI. Having said this I have found "leakage" occurs when trying to block the flow using an immersed solid. The problem is that the solver applies a scaling factor, but when the velocity is zero the scaling factor doesn't do much. I guess just see how high you can make the scaling factor before convergence becomes too difficult.
hi,i did as you said and set the expert parameter "smooth inside ims = t",but i occoured an error as fllowing! i do not know what to deal with it?
ERROR #001100000 has occurred in subroutine EPORT_OBSOLETE_PRM. Message: The following unused Expert Solver Parameter was found: || SMOOTH INSIDE IMS | The parameter may be incorrectly spelled.

can you tell me what's up with it ? thank you !

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