CFD Online Discussion Forums - [solids4Foam] pointD BCs for FSI with fixedDisplacementZeroShear BCs

Hello,

I am trying to validate solids4Foam FSI for arterial flows.

My validation case is a Moens-Korteweg situation with a pressure jump at t=0, using a short 3d tube geometry as in:

Lee, S. H., Choi, H. G. and Yool, J. Y. (2012) ‘Finite element simulation of blood flow in a flexible carotid artery bifurcation’, Journal of Mechanical Science and Technology, vol. 26, no. 5, pp. 1355–1361 [Online]. DOI: 10.1007/s12206-012-0331-9.

The case is quite similar to the 3dTube tutorial, but with a full 3d tube instead of the 2 symmetry conditions.

I started with the rigidly fixed BCs at inlet and outlet:

Code:

D: 



type           fixedDisplacement;

value          uniform (0 0 0);

Code:

pointD:





type fixedValue;

 value uniform (0 0 0);

with good results, then switched to radially moving inlet and outlet BCs using the fixedDisplacementZeroShear BC:

Code:

D:





type fixedDisplacementZeroShear;

 refValue uniform (0 0 0);

value uniform (0 0 0);

This does result in a nice expansion of the tube, but the pointD and pointDD BCs do not match that expansion:

Code:

pointD/pointDD:





type fixedValue;

 value uniform (0 0 0);

I have tried using

Code:

calculated

for pointD and pointDD, which seems to fix part of the problem (but doesn't make sense mathematically and seems to be unstable).

Which BC for pointD is compatible with fixedDisplacementZeroShear? Or which combination of BCs can I use to allow for movement in the plane?

Another one:

Is there a BC that will provide a non-reflective BC on the outlet side for the fluid? But I will put that in a separate thread.

Thanks
T