[srireddyn]

Hi,

I want to carryout a simulation of oscillating plate (1-DOF) in still water and compute the hydrodynamic force acting on the plate. See the attached figure for problem definition.

I tried to model it as a FSI(2way) problem with Transient Structural module and CFX. I defined a revolute joint and defined oscillatory joint motion. But CFX throws an error ( ANSYS failed to communicate mesh displacement). But simulation is working when I fix the bottom face (no rev. joint in this case)of the plate and apply a bending force to oscillate the plate.

I can't figure out what is the exact problem and how to rectify it.

please help!

[Krzychu (Chris)]

Hi Srinivasa,

is the ANSYS simulation alone converging? The solid domain problem seems to me to be unsolvable by itself. Check the ANSYS out file for error and convergence info.

Also for the rigid case you probably don't need to use the FSI. You could use probably use a moving boundary with prescribed motion. That is if you are interested more in the fluid domain than in the solid.

Cheers
Krzuchu

[srireddyn]

Originally Posted by Krzychu (Chris)

Hi Srinivasa,

is the ANSYS simulation alone converging? The solid domain problem seems to me to be unsolvable by itself. Check the ANSYS out file for error and convergence info.

Also for the rigid case you probably don't need to use the FSI. You could use probably use a moving boundary with prescribed motion. That is if you are interested more in the fluid domain than in the solid.

Cheers
Krzuchu

hi Krzuchu,

Thanks for your replying.
The Ansys simulation(Transient Structural) alone is converging. I have checked this several times.

As you said, for rigid body case we can use moving boundary but when the displacements are large we need to consider the remeshing region to avoid fatal errors due to Negative Cell Volumes.

As far as I know, there are two methods for remeshing. 1. using ICEM mesh replay file 2. User defined.

ICEM replay method can only accommodate translation of the boundary and can't be used for general motion. (see pdf Document: Ansys CFX Reference Guide).

I have no idea about user-defined. In this case we responsible for Data extraction(to modify the Geometry), Geometry modification, remeshing and then supply it to CFX to pre-process and solve.

I am simultaneously trying in Ansys Fluent with Dynamic mesh. In this case I have to write UDF (user defined function) to specify the motion. I succeeded in simulating a 2D model in which boundary is translating and remeshing is done automatically with specified settings under the Dynamic Mesh options.

please share if any other ideas are there.

your valuable suggestions are very much required for my guidance.

[srireddyn]

please see the attached pictures of Ansys Dynamic remeshing.

mesh-0035.jpg

mesh-0037.jpg

mesh-0039.jpg

mesh-0041.jpg

mesh-0042.jpg