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#1 |
New Member
Join Date: May 2018
Posts: 1
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Hi,
I need to calculate second derivatives in CFX Post. I created an expression which works for something like ![]() "Velocity u.Gradient X" Basically I want to calculate something like ![]() I tried different things like Velocity u.Gradient X.Gradient X, but even (Velocity u * Velocity v).Gradient X doesnt work. Also creating an expression for lets say "grad_x_v_x = Velocity u.Gradient X" and then creating a new expression "grad_x_v_x.Gradient X" doesn't work. I am using version 18.2. Can anyone help? Thank you guys so much! |
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#2 |
Senior Member
Join Date: Jun 2009
Posts: 1,884
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Insert a User Defined variable, select scalar type.
Then, set equal to Velocity u.Gradient X MyUGradX = Velocity u.Gradient X Now, insert a new variable (any name) Select Gradient, and choose you MyUGradX, press Apply You should get MyUGradX.Gradient which represents MyUGrad.Gradient X, MyUGrad.Gradient Y, MyUGrad.Gradient Z Effectively, they should correspond to d2u/dx2, d2u/dydx, d2u/dzdx |
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cfx, expressions, post, variables |
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