Once you have extracted the 3D fields you can work loading them in Matlab.

Have a look here https://www.researchgate.net/post/How_can_I_obtain_energy_spectrum_from_a_given_3D_turbulent_flow_field

Animation can be easily done in Tecplot.

Thanks so much, Fillppo Maria Denaro.

Hi Mohammed Khalid Hossen

To get my energy spectrum plots from OpenFOAM, I usually follow this steps:

1. insert probes in your simulation, to record the values in every time step

2. I import them to matlab

3. I run this:

k=k(1:2000);

t=t(1:2000); %2000 time-steps in my case

dt = t(2) - t(1);

Fs = 1 / dt;

Fn = Fs / 2;

%%frequency calculation

nPoints=size(k(1,:),2);

nFFT = nPoints;

df = Fs/nFFT;

freq =(-Fn:df:Fn);

results_freq = fft(k(1,:),nFFT);

figure

loglog(freq(1:end-1),abs(fftshift(results_freq)))

dt = t(2) - t(1);

Fs = 1 / dt;% frequência de amostragem

Fn = Fs / 2; % frequência de Nyquist

nPoints=size(k(1,1:293174),2);

nFFT = nPoints;

df = Fs/nFFT;

freq =(-Fn:df:Fn);

results_freq = fft(k(1,1:293174),nFFT);

figure

loglog(freq(1:end-1),abs(fftshift(results_freq)))

with this I get something similar to the attached figure

Hi Pedro Xavier Ramos, Thanks so much. Your plots look like cool!

Do you know how can I fix the initial amplitude(Ea) and wave number (k0) in boxTrub ? I am doing homogeneous isotropic turbulence by BuoyantboussinesqPimpleFoam solver using openFoam.

Noted that, by default these are Ea=10 and k0=5 in boxTurb dict.

Mohammed Khalid Hossen

I'm sorry, but I only work with interFoam...

How does one plot it in a multiphase flow using multiphaseEulerFoam?

Thanks!

How does one plot it in a multiphase flow using multiphaseEulerFoam?

Thanks!

How does one plot it in a multiphase flow using multiphaseEulerFoam?

Thanks!

How does one plot it in a multiphase flow using multiphaseEulerFoam?

Thanks!

How does one plot it in a multiphase flow using multiphaseEulerFoam?

Thanks!

How does one plot it in a multiphase flow using multiphaseEulerFoam?

Thanks!

How does one plot it in a multiphase flow using multiphaseEulerFoam?

Thanks!

How does one plot it in a multiphase flow using multiphaseEulerFoam?

Thanks!

Masoumeh Hashempour Thank you for providing the valuable information on how to use OpenFOAM post-process utility to get spectrum. Can you please tell me how to get energySpectrum file for the system folder?