Question about turbulence outputs

[AlexGuntner]

Dear all,

I am performing LES simulations using the Smagorinsky model and would like to plot the ratio between resolved_tke and total_tke given by:

$k_{res} / (k_{res} + k_{sgs})$

Looking at the outputs from my simulations, I can see velocity_reynold_stress0,1,2,3,4,5 and velocity_stress0,1,2,3,4,5, however, I have been unable to find an explanation of these variables in the documentation. So far, I have guessed that velocity_reynold_stress0,1,2 refer to $\overline{u'u'}, \overline{v'v'}$ and $\overline{w'w'}$. Could you kindly confirm this?

Lastly, is there a way to directly output the total TKE or the modelled TKE from the simulation?

Best regards

[hgopalan]

There are no existing methods to output planes of subgrid scale energy. For the periodic flows, the 1-D statistics contains kegs if you use the one equation model.

I think the easier work flow would be to write out instantaneous slices at regular intervals in the areas you are interest in and then do a statistics calculation in python or Matlab. You can compute the mean velocity gradients and then use the algebraic expression for turbulent kinetic energy n the Smagorinsky model to estimate the modeled tke.

If you write in the netcdf format netCDF4 or xarray should work. For particle format, you can use the amex particle reader in the python tools folder within arm-wind.

For particles you can also use pvpython which comes with paraview. To sample the data into a different format and do an averaging. I usually do something as follows.
import sys

#Step 1: paraview.simple reader needs folder to start with plt so we rename 

import os 
totallist=os.listdir()
dirlist=[name for name in os.listdir(".") if os.path.isdir(name)] 
for i in range(0,len(dirlist)):
    dirname=dirlist[i]
    if(dirname[3:]=="plt"):
        continue 
    if(os.path.isdir(dirname)):
        newname="plt"+dirname[7:]
        print(dirname,newname)
        os.rename(dirname,newname)

#Step 2: Convert particle files to csv ; Have to run with pvpython 
from paraview.simple import *
import os 
totallist=os.listdir()
dirlist=[name for name in os.listdir(".") if os.path.isdir(name)] 
for i in range(0,len(dirlist)):
    print(dirlist[i])
    reader = AMReXBoxLibParticlesReader(FileNames=dirlist[i])
    SaveData(dirlist[i]+".csv", reader)

#Step 3: Average the files 
import glob 

files=glob.glob("plt*.csv")
print(files)
import numpy as np 
for i in range(0,len(files)):
    print(files[i])
    data=np.genfromtxt(files[i],delimiter=",",skip_header=1)
    x=data[:,0]
    y=data[:,1]
    z=data[:,2]
    if(i==0):
        ux=data[:,9]
        uy=data[:,10]
        uz=data[:,11]
    else:
        ux+=data[:,9]
        uy+=data[:,10]
        uz+=data[:,11]
uz=uz/len(files)
ux=ux/len(files)
uy=uy/len(files)

target=open("average.csv","w")
target.write("x,y,z,uz\n")
for i in range(0,len(x)):
    target.write(str(x[i])+","+str(y[i])+","+str(z[i])+","+str(ux[i])+","+str(uy[i])+","+str(uz[i])+"\n")
target.close()