CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > CFX

The mass flux pressure coefficient_FSI model

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

Like Tree1Likes
  • 1 Post By stumpy

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   December 7, 2015, 19:58
Default The mass flux pressure coefficient_FSI model
  #1
Member
 
Join Date: Mar 2009
Posts: 48
Rep Power: 17
az_f is on a distinguished road
I am modeling hypertension blood vessel with Reynolds number 700. I used mass flow at inlet and zero pressure at outlet. For FSI modeling the system is stable for E>2 MPa. But according to literature, the Young's Modulus is about 0.5 MPa. In that case the system behaves completely crazy and no convergence. If I used The mass flux pressure coefficient equal to 100, it can converge. Am I allow to use the mass flux pressure coefficient more than 1? any suggestion?

Regards
az_f is offline   Reply With Quote

Old   December 22, 2015, 11:22
Default
  #2
Senior Member
 
Join Date: Apr 2009
Posts: 531
Rep Power: 20
stumpy is on a distinguished road
The mass flux pressure coefficient value is completely case dependent. A value of 100 might be fine for one case, but much too large/small for another. Any positive value could be a valid value. The important thing is to make sure you are converging the quantities of interest. Make sure the case fails with smaller values (1, 10, 50 etc) and you can see the pressure oscillating and diverging. If you use a value that is too large then the solution will be stable but it will never converge so the results will be wrong.
az_f likes this.
stumpy is offline   Reply With Quote

Old   January 29, 2016, 19:41
Default
  #3
Member
 
Join Date: Mar 2009
Posts: 48
Rep Power: 17
az_f is on a distinguished road
Hi Stumpy
Thanks for your response. I'm modelling an artery with one inlet and one outlet. When I use the large coefficient of mass flux pressure, the mass flow rate at inlet and outlet are not equal and outlet mass flow is less than inlet. Does that mean it didn't converge?
I have to simulate very small Young' modulus <1 in aorta with high blood pressure. I did try higher Young's modulus with lower velocity flow first and slowly increase the flow and decrease the Young's modulus. It did converge with warning in stagger iterations and different mass flow at inlet and outlet (mass flux coefficient= 10). Any Suggestion?

Thanks a lot for your help
az_f is offline   Reply With Quote

Reply

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
Radiation in semi-transparent media with surface-to-surface model? mpeppels CFX 11 August 22, 2019 08:30
Error in Two phase (condensation) modeling adilsyyed CFX 15 June 24, 2015 20:42
Setting rotating frame of referece. RPFigueiredo CFX 3 October 28, 2014 05:59
Overflow Error in Multiphase Modelling with Two Continuous Fluids ashtonJ CFX 6 August 11, 2014 15:32
lid-driven cavity in matlab using BiCGStab Don456 Main CFD Forum 1 January 19, 2012 16:00


All times are GMT -4. The time now is 04:59.