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Boundary condition as function of local coordinate
Posted 29.07.2021, 05:35 GMT-4 Fluid & Heat, Computational Fluid Dynamics (CFD), Parameters, Variables, & Functions Version 5.6 0 Replies
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Dear all, my system is made of two subdomains, the external rectangle (with velocity inlet and pressure outlet conditions and a boundary stress on the interface with the cylinder) and the inner cylinder (velocity inlet u2=u and v2=v and pressure fixed in the rear stagnation point). In both systems the Stokes (creeping flow) equations are solved. The boundary stress (F1,F2) of domain 1 depends on two values, Mnnn and Mttn, which I want to prescribe in this way:
1) I want to prescribe a piecewise function "por(R,phi)" on the cylinder surface (R=radius of cylinder, phi=angle coordinate in cylindrical frame). (e.g. por=0.5 if 0°<theta<30°, por=0.1 if 30°<=theta<31.5° and so on)
2) I define two interpolation functions Mnnn(por) and Mttn(por) so that Mnnn and Mttn (and F1, F2 as a consequence) will be updated at each segment on the cylinder automatically by interpolation of some Mnnn and Mttn values that I provide.
My questions are:
A) what is the command to define the function por(R,phi)? How can I implement a local coordinate on the cylinder surface instead of using the cartesian coordinates?
B) how can I pass the function "por" to the interpolation functions "Mnnn" and "Mttn"?
Screenshot of the system is attached.
Thank you very much in advance. Best wishes. Kevin
Attachments:
Hello Kevin Wittkowski
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