Spectral resolution of FFT in a acoustic simulation
 

Hi everyone, I am trying to simulate the tonal noise of a centrifugal fan (with FW-H analogy model) and have a problem with the Post-processing.
To represent the tonal noise I have created a FFT but it seems that there are too little data points hence the resolution of the graph is not sufficient. I have tried decreasing the time step but to no avail. Is there something that I have missed?

Additional info: I have set the write frequency in the acoustic sources tab to 1

Resolution is limited by how long you record the signal, so run your simulation longer if you want more resolution. If say this data corresponds to time = 0 to 1 seconds of physical time. Run it for 2 seconds.

Maximizing the sampling frequency by setting it to 1 merely allows you to to reach a higher maximum frequency on the FFT (i.e. the range). It doesn't improve resolution.

Thank you!! I finally get it. I still have one question. My frequency max is set to 10 kHz. Do you know how to increase it?

What's your time-step size? Is it 1e-03 seconds?

5e-5 seconds