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User Defined Shear Dependent Viscosity
Posted 18.12.2018, 05:07 GMT-5 Fluid & Heat, Computational Fluid Dynamics (CFD), Materials Version 5.4 1 Reply
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I came across the exact same problem as mentioned in the linked threat. I am trying to define a dynamic viscosity based on the temperature / shear rate. However, I see no way of using the shear rate as an argument without using a predefined non-newtonian model. I have defined an analytical function Mu(T,spf.sr) within my material.
Can someone help me?
Update, I get the following error: - Feature: Time-Dependent Solver 1 (sol2/t1) Failed to find consistent initial values. Error in user-defined function. Function: comp1.mat1.def.Mu Failed to evaluate variable. Variable: comp1.mat1.def.mu, Defined as: unit s cf(unit Pa cfcomp1.mat1.def.Mu(comp1.T/unit K cf,unit s cfcomp1.spf.sr)) Failed to evaluate variable. Variable: comp1.spf.mumat, Defined as: comp1.mat1.def.mu Failed to evaluate variable. Variable: comp1.spf.mu, Defined as: comp1.spf.mumat Failed to evaluate variable. Variable: comp1.spf.mu eff, Defined as: comp1.spf.mu Failed to evaluate variable. Variable: comp1.spf.K stress tensorrr, Defined as: comp1.ur(2comp1.spf.mu eff) Failed to evaluate expression. Expression: d((2((comp1.p-comp1.spf.K stress tensorrr)test(comp1.ur)-comp1.spf.K stress tensorrztest(comp1.uz)+(comp1.p-comp1.spf.K stress tensorphiphi)if(abs(r)<0.001h spatial,test(comp1.ur),test(comp1.u)/r)-comp1.spf.K stress tensorzrtest(comp1.wr)+(comp1.p-comp1.spf.K stress tensorzz)test(comp1.wz))pir)(dvol spatial),{test10}) Failed to evaluate Jacobian of expression. Expression: (2((comp1.p-comp1.spf.K stress tensorrr)test(comp1.ur)-comp1.spf.K stress tensorrztest(comp1.uz)+(comp1.p-comp1.spf.K stress tensorphiphi)if(abs(r)<0.001h spatial,test(comp1.ur),test(comp1.u)/r)-comp1.spf.K stress tensorzrtest(comp1.wr)+(comp1.p-comp1.spf.K stress tensorzz)test(comp1.wz))pir)*(dvol spatial) Last time step is not converged.