Plotting a Frequency Response for Selected Nodes using pyDPF

[dhabar95]

Aim: I have performed full harmonic analysis and obatined the nodal displacements, using pyMAPDL along with other results , in my .RST file. Now using the example (https://dpf.docs.pyansys.com/version/stable/examples/03-harmonic_analyses/00-multi_harmonic.html#sphx-glr-examples-03-harmonic-analyses-00-multi-harmonic-py) as a reference, I want to plot a similar frequency response (not multi-harmonic) for nodal x- displacement for specific nodes I am interested in.

Problems:

1. The example mentions about "Engine Orders"/RPMs, which I am not fully aware what it is. My simulation has 1 Load Step and 10 Substeps and I have no idea what are their corresponding RPM, as illustrated in another example(https://dpf.docs.pyansys.com/version/stable/api/ansys.dpf.core.time_freq_support.html).

2. The multi-harmonic example, plots the response for 2 nodes (node id 18, node id 2). But in case of an averaged nodal x-displacement values, will the "ansys.dpf.core.operators.averaging package" be the best choice, considering the use of fft_eval() later?

3. Is there any source I can refer about the "component_numbers" as I can only see (https://dpf.docs.pyansys.com/version/stable/api/ansys.dpf.core.operators.math.fft_approx.html#ansys.dpf.core.operators.math.fft_approx.InputsFftApprox.component_number) under "property component_number" there is mentioning about what number 0 and 1 corresponds to.

Thanks in advance for your time.