Discussion Forum

Dear Comsol Users, I am working in Comsol to model the fluid dynamics in an artery with the presence of a stenosis. I am interested in the pressure pulse wave propagation in an artery with a stenosis. The end goal is to model the pressure wave with fluid structure interaction (solid mechanics + laminar flow) in 2D fully coupled model. This to study the influence of material properties on the pressure wave.

But first I wanted to define good boundary conditions for the flow, so I modeled a simple 2D tube with a realistic pressure wave as inlet in mmHg (figure 1), with suppressed backflow. To avoid influence from the outlet conditions on the pressure wave I made a tube with a length of 5 meter and an outlet condition of 0 mmHg. 5 cm from the inlet a narrowing is located to simulate a stenosis.

By running the time dependent study the model gives some proper results: a local pressure difference and an increased velocity close to the stenosis.

But to analyze the pressure pulse wave I need a resulting dataset with a pressure wave with a high resolution. The input wave has a timestep of 0.01s and a period of 1 second , so I set the time dependent study with range(0,0.01,2). Despite a small mesh size (0.0001 for the first 20 cm and fine mesh for the long tube) the measured pressure pulse misses detail. I evaluated it with line average as well with point evaluation. The difference between both results was very small. I attached two plots, the set inlet pressure and the measured pressure at x=1cm. Also curves with a longer distance from the inlet showed pore resolutions. It can not be affected by wall conditions by the fact I did not model it in fluid structure interaction.

My question is: What is the cause of the lacking details in the pressure wave and how can I increase the details in the pressure wave?