CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > ANSYS > FLUENT

Two way FSI Aortic Valve / Blood Flow

Register Blogs Members List Search Today's Posts Mark Forums Read

LinkBack Thread Tools Search this Thread Display Modes
Old   July 22, 2015, 10:24
Default Two way FSI Aortic Valve / Blood Flow
New Member
Philipp Schmidt
Join Date: Apr 2015
Posts: 3
Rep Power: 11
PhiSch is on a distinguished road
Hey all,

I want to simulate the blood flow through an aortic valve. I started with modeling a simple tube with a velocity profile at the inlet and a pressure function, depending on the volumetric flow rate and a resistance coefficient at the outlet. The wall could deform in reaction to the pressure changes caused by the bc's. This worked fine.

In the next step I tried to implement some simple flaps into the tube.
Parameters for the flap material are:
Density: 500 kg/m
Young's Modulus: 0.5 MPa
Poisson's Ratio: 0.4
Thickness: 0.5 mm

Fluid parameters:
Density: 1105 kg/m
Non-newtonian fluid

When only the flaps are allowed to deform (the vessel wall is rigid) the solution also worked. I put an Under Relaxation Factor of 0.005 for the fluid --> solid data transfer in the system coupling tab.

If now the vessel wall is also allowed to deform, the solution won't converge under any circumstances i've tried. I modified the URF, tried Solution Stabilization (Dynamic Mesh tab) within fluent, but nothing helped.
All I know is, that the model needs to be under relaxated, but the parameters that do this are not clear to me.
Also for me it is hard to understand why each problem itself works, but the complete package does not.

It would help a lot, if somebody who dealt with similar problems could give me a hint.

Best regards
PhiSch is offline   Reply With Quote

Old   July 27, 2015, 04:59
New Member
Join Date: Jul 2015
Posts: 4
Rep Power: 10
naikpk is on a distinguished road
Hey ,

I am working on similar type of problem.
In my case the valve has following physical properties
E=1.5 Mpa
poisson`s ratio=0.49
thickness=0.5 mm

and blood
rho=1000 kg/m^3

Now when I am using air instead of blood the setup is running without any problems but when I am using blood as a fluid I am getting error saying : Excessive distortion of elements .

In my case only the valve is allowed to deform not the vessel.At inlet I have given a sinusoidal velocity pulse having amplitude 0.2m/s and outlet a constant 0 Pa pressure.

Do you have any idea how do I solve this problem ?
Also how did you come up with value of under relaxation factor ?
naikpk is offline   Reply With Quote

Old   July 27, 2015, 05:26
New Member
Philipp Schmidt
Join Date: Apr 2015
Posts: 3
Rep Power: 11
PhiSch is on a distinguished road

I got the same error, because the pressure at the interface walls diverged and therefor the forces passed by fluent were way too high.
It worked for me when I monitored the pressure at the interface walls and adjusted the factor until it didn't diverge any more.

But due to the factor you need many coupling steps within a time step. You should monitor the deformation at the valve tip, so you can see if the deformation is converged.
PhiSch is offline   Reply With Quote

Old   October 18, 2016, 14:24
Default Similar problem
New Member
Mazen Abou Gamrah
Join Date: Oct 2016
Posts: 4
Rep Power: 9
Mazen91 is on a distinguished road
Hey guys,

I am trying to work on a similar problem as you but unfortunately I am stuck with a problem. The leaflets (flaps) in my model are not visible in the cfx setup since they are surface bodies. I gave them a thickness of 1mm in the structural setup and suppressed the fluid volume (tube). In the cfx mesh I suppressed the leaflets and I meshed the fluid volume. After linking the blocks when I open the cfx setup I can not pick the leaflets as interfaces. In fact they just disappear from the model. If you guys can give me any tips on how the CAD should be modified (CATIA) or what I should do in the setup I would be very grateful.

Mazen91 is offline   Reply With Quote


blood, fsi, fsi 2-way coupling, valve

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Issues on the simulation of high-speed compressible flow within turbomachinery dowlee OpenFOAM Running, Solving & CFD 11 August 6, 2021 06:40
Mass flow rate prediction of Purge control valve using set pressure drop enr_venkat CFX 11 February 27, 2014 11:30
Gate valve flow simulations... nikesh FloEFD, FloWorks & FloTHERM 5 January 28, 2014 01:31
Compressible flow in CFX, valve simulation bnicholls92 CFX 3 January 13, 2014 04:18
Ball valve flow in solidworks nikesh FloEFD, FloWorks & FloTHERM 10 December 10, 2013 08:40

All times are GMT -4. The time now is 21:41.