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Normal derivative of a quantity on a surface
Posted 9 mag 2023, 09:37 GMT-4 Computational Fluid Dynamics (CFD), Modeling Tools & Definitions, Results & Visualization Version 6.0 0 Replies
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Hello, I am using the stokes flow module in Comsol 6.0. I have a curved boundary on which I impose a no-slip condition (i.e. flow has v=0 on the boundary). I would like to compute the derivatives of some quantities (p, u...) along the surface normal and tangent vectors.
I know there exist dtang for the tangential derivative, but is there a similar thing for the also for the normal-to-the-surface derivative?
For some quantity that we call "q", I rewrote the normal derivative as
dq/dn=dq/dx nx + dq/dy ny,
but this causes me problems because some quantities have discontinuous derivative in the (x,y) framework but not in the (n,t) framework. I need a function to evaluate directly the normal derivative of q without passing by the (x,y) decomposition.
Thanks in advance. Best, Kevin
Hello Kevin Wittkowski
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