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October 27, 2020, 06:03 |
Implementing FFT in Field Function
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#1 |
New Member
Madrigal
Join Date: Oct 2020
Location: Germany
Posts: 19
Rep Power: 5 |
Hello everybody,
I am new to this forum and a doctoral student. I am currently using Star CCM+ to simulate fluids flowing down a wire. This works very well. I use a field function on the inlet to set the speed of the fluid, which then flows down the wire. Using another field function, I now generate a forced disturbance (frequency) in the flow (sinus function). Using post-processing (FFT) I also find the frequency of the disturbance at the inlet. Now to my question: I have seen in different publications that also a white noise was simulated. For this I must add to my above mentioned field function for the velocity an another field function, instead of the forced interference frequency (see picture). For this I must add to my above mentioned field function for the velocity another, instead of the forced interference frequency (see attached Thumbnails). How should I implement the lower equation as a field function ? I would be super grateful if someone could help me . best regards CFD2DXY |
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November 3, 2020, 09:28 |
Table/Fieldfunktion Problem
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#2 |
New Member
Madrigal
Join Date: Oct 2020
Location: Germany
Posts: 19
Rep Power: 5 |
Hello everybody,
I have now solved the problem with the help of a matlab code. I was able to generate random values with a function. Now I am confronted with the problem that I want to add a random value to my function for the velocity at the inlet (radial profile) at every time step. I have written the following field function: ${velocity u} + interpolateTable(@Table("file"), "column1", LINEAR, "column0",${TimeStep}) where column1: timestep from 0 to 8 seconds and column0: Random value, which should be added to the field function at each time step. I have started the simulation but still have a constant inlet-speed. Does anyone have an idea what my error could be? Greetings |
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November 3, 2020, 11:30 |
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#3 | |
New Member
Madrigal
Join Date: Oct 2020
Location: Germany
Posts: 19
Rep Power: 5 |
Quote:
${velocity u} + interpolateTable(@Table("file"), "column1", LINEAR, "column0",${Time}) greetz |
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