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Strainrate to find Viscosity

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In the non-isothermal fluid physics, I prescribe certain velocity field boundary conditions and solve for the velocity field as a function of time. I would like to use the strain rate of the velocity field to also calculate the viscosity of the fluid during each iteration of the simulation. The strain rate depends on the partial spacial derivatives of the velocity components, i.e. ux, uy, uz, vx, etc. However, when I try to define the strain rate/viscosity as a function of these variables either within the Component or within the Material node, ux, uv, uz, etc. are considered undefined, and the function is not allowed. Any suggestions/solutions on how I can/should approach this issue would be greatly appreciated. Thank you!

Carter


0 Replies Last Post Jul 13, 2018, 9:25 a.m. EDT
COMSOL Moderator

Hello Carter Hamilton

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