SimScale CAE Forum

Simulating incompressible flow in a pipe with time-dependent diameter

Dear all,

Does anyone know how to setup transient simulation of incompressible flow in a pipe of which diameter changes over time in SimScale? The pipe will dilate first for a brief period of time and then return to steady-state size.

I have successfully done steady-state and transient simulation of incompressible flow in a rigid pipe using SimScale. However, I do not know how to make the pipe diameter varying over time. I went through all boundary conditions but none was useful. I found some deformation projects in SimScale but they were for “solid mechanics”. I also found two posts in the forum about “Fluid-Structure Interaction” which suggested that SimScale didn’t have this feature yet at least in 2017. Is there any way to simulate incompressible with time-dependent pipe diameter in SimScale at this moment? If not, I may have to try other platforms.

Thanks in advance for your comments.

Xiaowei

Hi Xiaowei (@zouxiaowei_thu)!

This is not yet possible on our platform if you mean that you want to physically deform the geometry during the simulation which would also require a moving mesh and maybe an adaptive mesh as well. Is this some geometry like a backward facing step or a diffuser with a certain angle that varies over time? And can you tell me what the application of that would be?

P.S.: FSI (Fluid-Structure Interaction) is still not possible on our platform.

Best,

Jousef

Dear jousef,

Thanks for your comment.

The project is trying to simulate blood flow in arteriole when brain is activated by a stimulus. Biologically, when a brain region is activated by a task, the arteriole will dilate and blood flow will increase for a brief period of time and then return to steady state. We could like to simulate the transient blood flow rates during this process, in conjunction with downstream structures which will be added future. This blood flow rates would help us understanding the source of functional magnetic resonance imaging signal.

The “pipe” here is intended to be an arteriole. The initial condition would be steady state. Then when simulation start, the pipe’s diameter will be increase (arteriole dilation) for a brief period of time and then decrease to steady state size. So I think your understanding is right - this requires physically deform the geometry during the simulation which would also require a moving/adaptive mesh.

Based on our conversation, it looks like I have to find other platforms to simulate this project. But please feel free to let me know if you have any other question. I am very new to CFD so I might miss some possible options to solve this problem.

Thanks
Xiaowei

Hi @zouxiaowei_thu and sorry for the delay.

Let me think about this and get back to you as soon as I have a specific idea but as mentioned physical deformation in the context of Fluid-Structure interaction is still not possible. Keeping you up-to-date!

Best,

Jousef