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 The information provided may be out of date.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.
Moving Mesh, CFD and automatic remeshing
Posted 2012年6月8日 GMT-4 07:54 Computational Fluid Dynamics (CFD), Mesh Version 4.2a 1 Reply
Please login with a confirmed email address before reporting spam
Hi all,
again.
I am simulating a moving plate, subject to shear stress, inside a pipe, much like a rigid flag subject to wind (in 2D it is a small rectangle bar).
As of now, I am currently using Moving Mesh and the Laminar Flow module. And a Global Equation (as per Ivar suggestion) in the Laminar Flow module to get the total force.
I have prescribed Mesh displacement to move the plate, and no slip at the plate boundaries, but the wake appears to be filled with fluid with zero velocity, and I get inverted elements upon simulating for a bit.
Anything obvious I am missing? Shouldn't 'no slip' from Laminar Flow and the mesh smoothing be enough?
Concerning the inverted elements: I am trying to set a stop condition (tick automatic remeshing at the solver) so that it remeshes when mod1.ale.relVolMin < "something"
I tried with something = 0.9 or 0.5 and both give me an error. The solver gets to a certain point and the simulations ends with:
- Feature: Automatic Remeshing (sol1/null/t1/arDef)
- Error: Nonlinear solver did not converge.
What am I missing? Shouldn't it just remesh and then keep on solving? Does the solver know enough to use the new mesh?
Thank you for your time
again.
I am simulating a moving plate, subject to shear stress, inside a pipe, much like a rigid flag subject to wind (in 2D it is a small rectangle bar).
As of now, I am currently using Moving Mesh and the Laminar Flow module. And a Global Equation (as per Ivar suggestion) in the Laminar Flow module to get the total force.
I have prescribed Mesh displacement to move the plate, and no slip at the plate boundaries, but the wake appears to be filled with fluid with zero velocity, and I get inverted elements upon simulating for a bit.
Anything obvious I am missing? Shouldn't 'no slip' from Laminar Flow and the mesh smoothing be enough?
Concerning the inverted elements: I am trying to set a stop condition (tick automatic remeshing at the solver) so that it remeshes when mod1.ale.relVolMin < "something"
I tried with something = 0.9 or 0.5 and both give me an error. The solver gets to a certain point and the simulations ends with:
- Feature: Automatic Remeshing (sol1/null/t1/arDef)
- Error: Nonlinear solver did not converge.
What am I missing? Shouldn't it just remesh and then keep on solving? Does the solver know enough to use the new mesh?
Thank you for your time
1 Reply Last Post 2012年6月9日 GMT-4 05:19
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
Hi
have you tried a few of the model library examples, there and on the web site there are a few models even wit flexing "flags". You will perhaps notice that often one cuts the fluid mesh with a few guiding lines at the "solid edges", these move around with the mesh, but are there to help to define the mesh motion such that you get less mesh inversion.
This set-up is rather impirical and you need to get the correct feeling by doing, so its "just" to try and go ahead
--
Good luck
Ivar
have you tried a few of the model library examples, there and on the web site there are a few models even wit flexing "flags". You will perhaps notice that often one cuts the fluid mesh with a few guiding lines at the "solid edges", these move around with the mesh, but are there to help to define the mesh motion such that you get less mesh inversion.
This set-up is rather impirical and you need to get the correct feeling by doing, so its "just" to try and go ahead
--
Good luck
Ivar