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surface integration of normal velocity of complex geometry (solid domain)
Posted Jun 24, 2012, 2:10 p.m. EDT 2 Replies
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Dear all,
I am using the acsl toolbox in COMSOL 4.2 and would like to calculate the power that is injected from my solid domain into my fluid domain. In order to do that I use the "surface integration" function in the "derived values section". The formula requires the complex conjugate of the normal velocity. In the "expression section", however, I can only find the x-y-z components of the velocity and the velocity amplitude. As the surface orientations vary strongly from one surface to another, I cannot simply calculate the cross product. Is there an easy way to obtain the normal velocity for my problem (maybe by using a boundary coordinate system). Also, my geometry is somewhat cylindrical and I need all normal velocities to point into the "cylinder".
Thank you very much for your help.
Kind regards,
Martin
I am using the acsl toolbox in COMSOL 4.2 and would like to calculate the power that is injected from my solid domain into my fluid domain. In order to do that I use the "surface integration" function in the "derived values section". The formula requires the complex conjugate of the normal velocity. In the "expression section", however, I can only find the x-y-z components of the velocity and the velocity amplitude. As the surface orientations vary strongly from one surface to another, I cannot simply calculate the cross product. Is there an easy way to obtain the normal velocity for my problem (maybe by using a boundary coordinate system). Also, my geometry is somewhat cylindrical and I need all normal velocities to point into the "cylinder".
Thank you very much for your help.
Kind regards,
Martin
2 Replies Last Post Jun 26, 2012, 1:16 p.m. EDT
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Posted:
1 decade ago
Hi
normally you have the surface normal fields (nx, ny, nz) and the local boundary normal vector, so if you dot those with your velocity vector( u,v,w) you should be able to get the normal component for your integration
The doc in v4.3 is nicely updated and all (at least most) variables are now described in details, this helps to understand what is what, but you still have the equaton view with the description and full eqations, apart that they are in an unsorted order so you must run through the full list to find your value
--
Good luck
Ivar
normally you have the surface normal fields (nx, ny, nz) and the local boundary normal vector, so if you dot those with your velocity vector( u,v,w) you should be able to get the normal component for your integration
The doc in v4.3 is nicely updated and all (at least most) variables are now described in details, this helps to understand what is what, but you still have the equaton view with the description and full eqations, apart that they are in an unsorted order so you must run through the full list to find your value
--
Good luck
Ivar
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Posted:
1 decade ago
Hi,
Thank you for your help! I will try to implement what you suggested!
Kind regards,
Martin
Thank you for your help! I will try to implement what you suggested!
Kind regards,
Martin