Search found 110 matches

by Weiguang Yang
Thu May 30, 2024 12:05 pm
Forum: SimVascular: Cardiovascular Modeling and Simulation Application
Topic: Deformable Wall Simulations
Replies: 3
Views: 1596

Re: Deformable Wall Simulations

For CMM, the assumption is that because of a small deformation, say <10% change relative to the diameter during the cycle, the mesh is stationary. i.e. the coordinates of the mesh nodes remain unchanged but the traction forces on the wall nodes change. In a severe stenosis, allowing a deformable wal...
by Weiguang Yang
Wed May 29, 2024 1:34 pm
Forum: SimVascular: Cardiovascular Modeling and Simulation Application
Topic: Deformable Wall Simulations
Replies: 3
Views: 1596

Re: Deformable Wall Simulations

If you use svFSI, there is an example that "prestresses" the geometry to match the reference geometry based on medical images. Please see https://github.com/SimVascular/svFSI-Tests/tree/master/07-fsi/ale/04-pipe_prestress If you use svSolver's coupled momentum method, the presolver needs a pressure ...
by Weiguang Yang
Thu May 02, 2024 1:27 pm
Forum: SimVascular: Cardiovascular Modeling and Simulation Application
Topic: Problem simulating simple geometries (negative pressures)
Replies: 12
Views: 4957

Re: Problem simulating simple geometries (negative pressures)

Yes, I also realized that it could be explained by the conservation of energy. For a short diverging pipe, the energy loss can be neglected. The flow slows down when it enters a region with a larger cross-sectional area. The kinetic energy is converted into a potential. So the dynamic pressure is re...
by Weiguang Yang
Mon Apr 29, 2024 11:40 pm
Forum: SimVascular: Cardiovascular Modeling and Simulation Application
Topic: Oscillating pressure curves
Replies: 6
Views: 8181

Re: Oscillating pressure curves

Regarding solver.inp, I don't notice anything particularly wrong. Could you please specify what parameters you set in the svpre file? I may try to downsample your inflow.flow from 781 to approximately 100 data points while applying some smoothing. For the svpre file, consider reducing the number of ...
by Weiguang Yang
Thu Apr 25, 2024 9:44 pm
Forum: SimVascular: Cardiovascular Modeling and Simulation Application
Topic: Problem simulating simple geometries (negative pressures)
Replies: 12
Views: 4957

Re: Problem simulating simple geometries (negative pressures)

The model is quite short relative to its diameter. I am wondering if you have tried an expansion vessel with a larger length. My intuition is that the prescribed inflow (125 ml/s) has a sufficient momentum to reach outlet even though outlet pressure is higher by 150 dyn/cm^2 which is only 0.1 mmHg. ...
by Weiguang Yang
Mon Apr 22, 2024 6:39 pm
Forum: SimVascular: Cardiovascular Modeling and Simulation Application
Topic: Oscillating pressure curves
Replies: 6
Views: 8181

Re: Oscillating pressure curves

Could you grant me the access to your files so that I can take a look?
Thanks!
by Weiguang Yang
Tue Feb 27, 2024 5:47 pm
Forum: SimVascular: Cardiovascular Modeling and Simulation Application
Topic: Impedance Boundary condition
Replies: 3
Views: 1780

Re: Impedance Boundary condition

Impedance BC cannot be prescribed via the SV GUI. It is not used as often as RCR. To use impedance BC, you need to prepare two files impt.data and Qhistor.dat in order to compute the impedance convolution. impt.dat has a format similar to rcrt.dat. Each block represent a set of impedance for an outl...
by Weiguang Yang
Tue Jan 16, 2024 6:35 pm
Forum: SimVascular: Cardiovascular Modeling and Simulation Application
Topic: Distal Pressure in RCR Model
Replies: 1
Views: 894

Re: Distal Pressure in RCR Model

I expect to see a pressure difference of 20 Pa instead of 40 Pa. Can you check if the two rcrt.dat files differ in the last two rows only. Take the rcrt file used in the Simvascular cylinder demo project as an example. The original Pd was prescribed as follows, 0.0 0.0 1.0 0.0 To change to Pd=20Pa, ...
by Weiguang Yang
Tue Aug 29, 2023 10:07 am
Forum: SimVascular: Cardiovascular Modeling and Simulation Application
Topic: RCR boundary condition
Replies: 1
Views: 1032

Re: RCR boundary condition

The rules for distributing resistance are based on the assumption that flow is proportional to A^alpha. When alpha equals 1, the outflow is proportional to the outlet area. Similarly, the capacitance is proportional to the outlet area. The total capacitance is the sum of each outlet's capacitance wh...
by Weiguang Yang
Wed Apr 19, 2023 10:30 am
Forum: SimVascular: Cardiovascular Modeling and Simulation Application
Topic: About "Split Resistance" option
Replies: 1
Views: 825

Re: About "Split Resistance" option

To my knowledge, the resistance split doesn't take account of the 3D model resistance of the 3D model. It just distributes the total resistance you provide following a power law. If we assume the pressure across the resistors is the same (i.e. in parallel), the resistance is split such that Q is pro...