Flow Through an Immersed Solid !

kimiaghalam · September 14, 2011, 00:18

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, 06:49

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, 10:27

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, 07:05

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, 05:56

Quote:

Originally Posted by stumpy

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 !

September 14, 2011, 00:18	Flow Through an Immersed Solid !	#1
kimiaghalam New Member morteza Join Date: Jul 2009 Location: United States Posts: 12 Rep Power: 17	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 ?

September 14, 2011, 06:49		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,852 Rep Power: 144	The immersed solid approach uses a factor to slow the flow, I can't remember its name. Have you set this factor high enough? kimiaghalam likes this.

September 14, 2011, 10:27		#3
stumpy Senior Member Join Date: Apr 2009 Posts: 531 Rep Power: 21	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. kimiaghalam and wc34071209 like this.

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May 25, 2012, 07:05		#4
belgacem New Member belgacem Join Date: Jan 2012 Posts: 22 Rep Power: 14	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!