can Rigid body be used in a FSI simulation?

zhou467 · August 4, 2010, 00:06

Hello, I am trying to do a FSI simulation. It's a spinnin screw immersed in some viscous fluid. I want to set the solid as a rigid body in the transient structural analysis. However, if I do so, I cannot define "fluid solid interface". Can anyone give me some help? Thanks in advance.

stumpy · August 4, 2010, 17:46

No, you can't do that. Only flexible bodies can be used on the structural side. Where does FSI come in? Why not just define moving boundaries in CFX, or use the Rigid Body Solver in CFX?

ghorrocks · August 4, 2010, 20:36

CFX V13 has a full 6DOF rigid body solver build in. Download the trial version and give it a try.

belgacem · May 25, 2012, 14:17

Hi
I’m using Ansys CFX V.13 and I need some head start.
I want to simulate wave generated by sliding mass (block). So, I’m supposed to simulate a wedge dropping the calm water surface. The 2-D transient simulation consisting of a wedge prism sliding down an inclined slope of 45°, with translation in the x and y-axis. In order to simulate the wedge falling, I used the Rigid Body Solver in Ansys CFX Pre 13. Noted that the Rigid body is defined as an Immersed Solid with two degree of freedom (x and y-axis). So, I give a density (or mass) to the block and I let it fall under gravity. I have specified a 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.
First,
Please, I want to know how to make the block stop moving on the bottom where the potential energy was equal to zero? The velocity of the block was needed to describe the Kinematic of the landslide and it should equal zero in the bottom. In my case, the block passes the bottom wall.
Second, the water still passes through the solid. I already use a very fine mesh.
I would very much appreciate it if you help me solve the following problem.

ghorrocks · May 26, 2012, 07:10

Read the documentation about stopping water passing through the body. I do not know off the top of my head how to fix your first question.

Ved1994 · October 2, 2017, 23:30

Quote:

Originally Posted by ghorrocks

Read the documentation about stopping water passing through the body. I do not know off the top of my head how to fix your first question.

How do I incorporate resistance to the movement in 6dof solver?

ghorrocks · October 3, 2017, 20:50

That depends on what 6DOF solver you are using. This is clearly explained in the documentation, so that is the best place to start learning about this.

August 4, 2010, 00:06	can Rigid body be used in a FSI simulation?	#1
zhou467 New Member Zhou Join Date: Aug 2010 Posts: 1 Rep Power: 0	Hello, I am trying to do a FSI simulation. It's a spinnin screw immersed in some viscous fluid. I want to set the solid as a rigid body in the transient structural analysis. However, if I do so, I cannot define "fluid solid interface". Can anyone give me some help? Thanks in advance.

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August 4, 2010, 17:46		#2
stumpy Senior Member Join Date: Apr 2009 Posts: 531 Rep Power: 21	No, you can't do that. Only flexible bodies can be used on the structural side. Where does FSI come in? Why not just define moving boundaries in CFX, or use the Rigid Body Solver in CFX?

August 4, 2010, 20:36		#3
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	CFX V13 has a full 6DOF rigid body solver build in. Download the trial version and give it a try.

May 25, 2012, 14:17		#4
belgacem New Member belgacem Join Date: Jan 2012 Posts: 22 Rep Power: 14	Hi I’m using Ansys CFX V.13 and I need some head start. I want to simulate wave generated by sliding mass (block). So, I’m supposed to simulate a wedge dropping the calm water surface. The 2-D transient simulation consisting of a wedge prism sliding down an inclined slope of 45°, with translation in the x and y-axis. In order to simulate the wedge falling, I used the Rigid Body Solver in Ansys CFX Pre 13. Noted that the Rigid body is defined as an Immersed Solid with two degree of freedom (x and y-axis). So, I give a density (or mass) to the block and I let it fall under gravity. I have specified a 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. First, Please, I want to know how to make the block stop moving on the bottom where the potential energy was equal to zero? The velocity of the block was needed to describe the Kinematic of the landslide and it should equal zero in the bottom. In my case, the block passes the bottom wall. Second, the water still passes through the solid. I already use a very fine mesh. I would very much appreciate it if you help me solve the following problem.

May 26, 2012, 07:10		#5
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	Read the documentation about stopping water passing through the body. I do not know off the top of my head how to fix your first question.

October 3, 2017, 20:50		#7
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	That depends on what 6DOF solver you are using. This is clearly explained in the documentation, so that is the best place to start learning about this.