Immersed Solid Valve Expressions

shzinwoyk · December 15, 2017, 03:45

Hello there,

I want to model a system using CFX with Immersed Solid. There is a bypass valve in the system. Rigid body and external force options do not fully cover my problem. For this reason, I created the motion equations of the valve myself. I have described Immersed Solid motion by the Specified Displacement method. the equations are giving the valve displacement value.

In the equation there is the position and velocity term of the Immersed Solid body. I am having problems from these expressions. I give the expression I used below.

areaAve (Total Mesh Displacement Y) @valve Wall
ave (Mesh Velocity Y) @valve

Valve Wall: valve's all walls (2D)
Valve: Valve Region (3D)

With the expression, I need an expression to calculate the position of the Immersed Solid Body every time step. At this point, I can define the valve displacement by using motion equations.

Do I have a chance to calculate the position of the Immersed Solid Body with the Specified Deisplacement method? Could you tell me about the expressions I need to use?

If necessary, I can describe the problem in more detail.

Best Regards

shzinwoyk · December 15, 2017, 05:01

The other question,

if i use the rigid body solution with Immersed Solid method, how am i limit the valve position.

For example:

There is a check valve in the system. This valve is loaded with 400N preload. If I can limit the position of the rigid body to a point, I can stop the movement of the rigid body in case the force is not balanced.

THX

Christophe · January 5, 2018, 01:15

Rbstate(Position X)@rigid body name will give you position In the X direction.

I've seen a write up of limiting the position by using a logic statement in the motion equation you write. Something like new position = old position + If(rbstate(position x@rbname > max position, 0, dX as a result of the user defined equation of motion)

December 15, 2017, 03:45	Immersed Solid Valve Expressions	#1
shzinwoyk New Member alper yıldırım Join Date: Feb 2014 Posts: 10 Rep Power: 12	Hello there, I want to model a system using CFX with Immersed Solid. There is a bypass valve in the system. Rigid body and external force options do not fully cover my problem. For this reason, I created the motion equations of the valve myself. I have described Immersed Solid motion by the Specified Displacement method. the equations are giving the valve displacement value. In the equation there is the position and velocity term of the Immersed Solid body. I am having problems from these expressions. I give the expression I used below. areaAve (Total Mesh Displacement Y) @valve Wall ave (Mesh Velocity Y) @valve Valve Wall: valve's all walls (2D) Valve: Valve Region (3D) With the expression, I need an expression to calculate the position of the Immersed Solid Body every time step. At this point, I can define the valve displacement by using motion equations. Do I have a chance to calculate the position of the Immersed Solid Body with the Specified Deisplacement method? Could you tell me about the expressions I need to use? If necessary, I can describe the problem in more detail. Best Regards

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December 15, 2017, 05:01		#2
shzinwoyk New Member alper yıldırım Join Date: Feb 2014 Posts: 10 Rep Power: 12	The other question, if i use the rigid body solution with Immersed Solid method, how am i limit the valve position. For example: There is a check valve in the system. This valve is loaded with 400N preload. If I can limit the position of the rigid body to a point, I can stop the movement of the rigid body in case the force is not balanced. THX

January 5, 2018, 01:15		#3
Christophe Member Join Date: Jan 2015 Posts: 62 Rep Power: 11	Rbstate(Position X)@rigid body name will give you position In the X direction. I've seen a write up of limiting the position by using a logic statement in the motion equation you write. Something like new position = old position + If(rbstate(position x@rbname > max position, 0, dX as a result of the user defined equation of motion)