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visualising time derivatives

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Old   November 9, 2012, 00:14
Default visualising time derivatives
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Hi everyone,

I hope that someone has a simple suggestions for what I'm trying to do. I basically want to plot the time derivative of for instance the x velocity in an unsteady simulation. I then want to export the x acceleration contour every N time steps.

Solution 1) Somehow create a new variable that calculates the x acceleration at every time step and then use the automatic export feature. I don't think this can be done using the Custom Field Function Calculator. Any ideas?

Solution 2) Write a UDF that calculates the x acceleration and writes it to an output file. I've found out about the C_U(c,t) and C_U_M1(c,t) functions which give me the x velocity from the current and previous time step, so it's easy to get the acceleration. But I'm having trouble with using thread_loop_c and begin_c_loop_all macros to access all cells/nodes on the surface of interested. Aside from that I wouldn't know how to save it in a format which allows the data to be easily visualised in Tecplot again.

Thanks for any thoughts/comments.
Dorit
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acceleration, contour, post procesing, time derivative, udf exporting variable

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