Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Blood flow in a Cerebral Aneurysm

Please login with a confirmed email address before reporting spam

Good morning, I'm simulating the blood flow in a brain aneurysm. I made a 2D geometry as if I were considering the central slice of the 3D structure (figure1), where the internal domain is blood and the two external domains are the artery. I set the following boundary conditions: I consider a laminar flow, with a pulsatile flow rate at the inlet as in figure 2 and at the outlet with zero static pressure. For the material properties I inserted a blood with 1060kg/m³ density and a dynamic viscosity of 0.0036 Pas, while the artery properties are in figure 3. The study selected is 'FluidSolid Interaction, Fixed Geometry'. I did a stationary study (with all default parameters) but there is the following error: "Failed to find a solution. Maximum number of segregated iterations reached. Returned solution is not converged. Not all parameter steps returned."

if someone can help me, I will be grateful. Thanks a lot.


1 Reply Last Post 02.12.2020, 15:07 GMT-5
Jeff Hiller COMSOL Employee

Please login with a confirmed email address before reporting spam

Posted: 4 years ago 02.12.2020, 15:07 GMT-5
Updated: 4 years ago 03.12.2020, 09:43 GMT-5

Hello Miriam,

I can't help but notice that your figure 1 shows a 2D axisymmetric geometry. I don't believe that's what you meant to do as it would not correspond to the central slice of a blood vessel with an aneurysm (One of the conditions required for 2D axisymmetry to be suitable is that the geometry be invariant about the r=0 axis). Even if you had used a 2D geometry, you couldn't expect that the simulation will yield any insight into the real 3D flow, since a blood vessel is not close to being infinitely invariant in the direction perpendicular to the screen. 3D is going to be a must for modeling this flow. Here is an example you can use as a starting point for your own modeling.

Best regards,

Jeff

-------------------
Jeff Hiller
Hello Miriam, I can't help but notice that your figure 1 shows a 2D axisymmetric geometry. I don't believe that's what you meant to do as it would not correspond to the central slice of a blood vessel with an aneurysm (One of the conditions required for 2D axisymmetry to be suitable is that the geometry be invariant about the r=0 axis). Even if you had used a 2D geometry, you couldn't expect that the simulation will yield any insight into the real 3D flow, since a blood vessel is not close to being infinitely invariant in the direction perpendicular to the screen. 3D is going to be a must for modeling this flow. Here is [an example](https://www.comsol.com/model/fluid-structure-interaction-in-a-network-of-blood-vessels-660) you can use as a starting point for your own modeling. Best regards, Jeff

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.