Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.
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.
different flow rate in input and output
Posted 20 lug 2012, 12:15 GMT-4 Fluid & Heat, Computational Fluid Dynamics (CFD), Studies & Solvers Version 4.3 1 Reply
Please login with a confirmed email address before reporting spam
Hi,
I am trying to model blood flow in the first section of the aorta when there is a ventricular assist device (VAD).
Artery model presents two inlet and four outlet:
- inlet 1 is a function variable in time, obtained by interpolation, that represents the cardiac output of 4 l/min
- inlet 2 is a constant flow of 1 l/min, that represents the outflow of the VAD, multiplied by a step function
- every outlet I have imposed a function representing a pressure variable with time
Then I use a condition of laminar inflow for the inlet and a condition of pressure without viscous stress for the outlet.
Initial conditions are zero, flow is incompressible and walls are regarded as rigid.
When I calculate the sum of the outflow is much greater than the sum of the inflow. WHY?
Thanks a lot
I am trying to model blood flow in the first section of the aorta when there is a ventricular assist device (VAD).
Artery model presents two inlet and four outlet:
- inlet 1 is a function variable in time, obtained by interpolation, that represents the cardiac output of 4 l/min
- inlet 2 is a constant flow of 1 l/min, that represents the outflow of the VAD, multiplied by a step function
- every outlet I have imposed a function representing a pressure variable with time
Then I use a condition of laminar inflow for the inlet and a condition of pressure without viscous stress for the outlet.
Initial conditions are zero, flow is incompressible and walls are regarded as rigid.
When I calculate the sum of the outflow is much greater than the sum of the inflow. WHY?
Thanks a lot
1 Reply Last Post 20 lug 2012, 14:22 GMT-4
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
Hi
my reaction is too : strange, not really logical !
Flux conservation should apply, I believe; but discrepancies can also be driven by poor resolutions of gradients due to mesh density issues. Have you checked the KB knowledge base on articles about flux integrations ?
--
Good luck
Ivar
my reaction is too : strange, not really logical !
Flux conservation should apply, I believe; but discrepancies can also be driven by poor resolutions of gradients due to mesh density issues. Have you checked the KB knowledge base on articles about flux integrations ?
--
Good luck
Ivar