[OpenFOAM] python calculator - laplacian(U) calculation

rol97 · July 12, 2021, 12:54

Hi everyone,
I am currently trying to evaluate through python calculator the laplacian of U, however such function only takes as input scalars. I wanted thus to write something similar to

Code:

laplacian(U_X)

however I cannot make it work, and I get this error message.

Code:

  File "/opt/paraviewopenfoam56/lib/python2.7/site-packages/paraview/calculator.py", line 192, in execute
    retVal = compute(inputs, expression, ns=variables)
  File "/opt/paraviewopenfoam56/lib/python2.7/site-packages/paraview/calculator.py", line 140, in compute
    retVal = eval(expression, globals(), mylocals)
  File "<string>", line 1, in <module>
NameError: name 'U_X' is not defined

Do you have any suggestion on how to evaluate such term?
Thanks in advance.

rol97 · July 14, 2021, 04:11

Nevermind, I figured it out, it is probably basic knowledge but I will explain anyway.
The syntax to extract the single component from the vector and evaluate the laplacian is

Code:

laplacian(U[:,0])

July 12, 2021, 12:54	python calculator - laplacian(U) calculation	#1
rol97 New Member Raoul Join Date: Apr 2021 Posts: 16 Rep Power: 5	Hi everyone, I am currently trying to evaluate through python calculator the laplacian of U, however such function only takes as input scalars. I wanted thus to write something similar to Code: laplacian(U_X) however I cannot make it work, and I get this error message. Code: File "/opt/paraviewopenfoam56/lib/python2.7/site-packages/paraview/calculator.py", line 192, in execute retVal = compute(inputs, expression, ns=variables) File "/opt/paraviewopenfoam56/lib/python2.7/site-packages/paraview/calculator.py", line 140, in compute retVal = eval(expression, globals(), mylocals) File "<string>", line 1, in <module> NameError: name 'U_X' is not defined Do you have any suggestion on how to evaluate such term? Thanks in advance.

July 14, 2021, 04:11		#2
rol97 New Member Raoul Join Date: Apr 2021 Posts: 16 Rep Power: 5	Nevermind, I figured it out, it is probably basic knowledge but I will explain anyway. The syntax to extract the single component from the vector and evaluate the laplacian is Code: laplacian(U[:,0])

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