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Find Inertial Modes, Eigenvalues for a Sphere of Fluid

Posted May 5, 2013, 4:42 p.m. EDT Fluid & Heat, Materials, Modeling Tools & Definitions, Parameters, Variables, & Functions, Studies & Solvers Version 4.3a 0 Replies

Alex Grannan
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I am new to Comsol and I am trying to find the eigenmodes of a rotating sphere filled with water in the rotating frame. I have specified the sphere filled with water with free slip walls, specified pressure points specified and the Coriolis force imposed with the volume force: F=(-2*v,2u,0). I have tried to set up the simplest mode, called the spin-over mode where I have prescribed the initial velocity to be solid body rotation around the y axis: U_0=(-z,0,x). I am not sure how to set up the problem for finding the eigenvalues in the fluid. In Comsol 3, the eigenvalue was found as a subset of a time dependent problem but I am not sure how to even setup this problem in Comsol 4.3a.The examples I have found seems to deal with solid structures or acoustics and not with fluids. I have include a bare bones file with non dimensional parameters assigned. When I run it I only get Nan for the eigenvalues. Thank you very any help or links to helpful documentation.

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0 Replies Last Post May 5, 2013, 4:42 p.m. EDT
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Hello Alex Grannan

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