Hello, I was wondering if somebody could give me a bit of advice how to correctly set problem involving fluid-structure interaction. The problem is: a flexible solid body oscillating in an inviscid liquid flow, large deformations. I'm myself a novice in this field, so I will appreciate any of your reccomendations. Good luck.

1. There are generally two ways. (1)First, moving mesh/grid method (finite element method) (2)Second, virtual boundary method(fixed mesh and add a forcing term to the governing eq.)

2. I have also interesting on FSI. I'm trying to Large Eddy Simulation of turbulent flow around moving cylinder using similar idea of 1 (2). Acutually the problem is still running. That means I need to check the results and calibration of my code.

3. The references of 1(2) is as follows;

(1) C.S. Peskin, Numerical analysis of blood flow in the hear, J. Comput. Phys. 25,220(1977)

(2)D. Goldstein et al, Modeling a No-Slip flow Boundary with an External force Field, J. Comput. Phys. 105, 354,366(1993)

(3) E.M. Saiki and S. Biringen, Numerical Simulation of a Cylinder in Uniform Flow: Application of a Virtual Boundary Method, J. Comput. Phys. 123,450-465(1996)

(4) E.A. Fadlun, et al, Combined Immersed-Boundary Finite-Difference Methods for Three-Dimensional Complex Flow simulations, J. Comput. Phys. 161, 35-60(2000).

Hi,

I guess you are interested in writing your own code to do this and the first response is a good one for it.

In case you are trying to solve some actual problem and would like to use a commercial CFD tool to do it, you may want to look at CFD-ACE+ from CFDRC (www.cfdrc.com). They use the moving mesh approach mentioned in the first response to your messege.

Hello,

Just in case, you are interested in any commercial code, you may want to look also into the fluidyn softwares. Fluidyn-FSI combines the finite element method for structures with the finite volume approach for fluids. The two solvers are strongly coupled through boundary conditions exchange. Check out the website at www.fluidyn.com

Amita

Our code, RADIOSS-CFD is used by industrial clients worldwide to solve FSI applications. You can find numerous exemples on our website www.mcube.fr under the M-Explicit applications section.

Regards,

Dimitri Nicolopoulos

Hi Alexander,

I am trying to do simulations of fluid behaviour during large scale boundary deformations. I have been using RADIOSS-ALE up until now without much success. Using an explicit code is difficult because as the elements distort the time step keeps reducing and hence the run time goes up. Also as the solids elements distort the model becomes unstable any way. If you fix the time step, then as the elements distort you develop an unwanted mass penalty which will make your results suspect as well. Look at Dimitri's answer to my question on this in this forum re: large scale deformations.

I am now looking at gridless methods such as SPH. I am still reading up on the subject, but overall I think it might be a winner in the longer term for this type of analysis. The only penalty is the run time will go up. I have been advised that there can be problems with boundary condition behaviour, but like I said, i'm still trying to get my head around it. If you want, email me and I will give you a list of the papers I have found on SPH. Please can you tell me if you are writing your own code for this. If you get a result on this or find any other info please could you let me know. All the best!

I am working on Fluid-structure interaction problem.It includes two bodies in tandem and one of them move continuously.I don't know how to generate the proper grid.Can you give me some help? Thanks a lot!