Postprocessing of divergence of U

sourav0921 · July 1, 2019, 08:42

Hi guys,

I am simulating the turbulent channel flow using PISOFOAM solver. I calculated the divergence of U using the command
pisoFoam -postProcess -func "div(U)"

But during calculation it shows a warning massage

'--> FOAM Warning : functionObjects::div div(U) cannot find required object U of type surfaceScalarField

Can you kindly tell me what causes this?'

yambanshee · July 8, 2019, 03:21

try just using the command

Code:

postProcess -func "div(U)"

sourav0921 · July 8, 2019, 06:27

I understood. But can you kindly tell me what is the difference between div (U) and div (phi) in case of incompressible flow solvers?

geth03 · June 20, 2022, 09:21

basically U is a vector and means velocity, phi is the volumetric flux on the faces of the cell. the output for both will be a volScalarField with the dimension 1/second for both. but the value will not be the same.

July 1, 2019, 08:42	Postprocessing of divergence of U	#1
sourav0921 New Member SOURAV GANGULI Join Date: Dec 2018 Posts: 11 Rep Power: 7	Hi guys, I am simulating the turbulent channel flow using PISOFOAM solver. I calculated the divergence of U using the command pisoFoam -postProcess -func "div(U)" But during calculation it shows a warning massage '--> FOAM Warning : functionObjects::div div(U) cannot find required object U of type surfaceScalarField Can you kindly tell me what causes this?'

July 8, 2019, 03:21		#2
yambanshee Senior Member Zander Meiring Join Date: Jul 2018 Posts: 125 Rep Power: 7	try just using the command Code: postProcess -func "div(U)"

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July 8, 2019, 06:27		#3
sourav0921 New Member SOURAV GANGULI Join Date: Dec 2018 Posts: 11 Rep Power: 7	I understood. But can you kindly tell me what is the difference between div (U) and div (phi) in case of incompressible flow solvers?

June 20, 2022, 09:21		#4
geth03 Senior Member Join Date: Dec 2019 Location: Cologne, Germany Posts: 355 Rep Power: 8	basically U is a vector and means velocity, phi is the volumetric flux on the faces of the cell. the output for both will be a volScalarField with the dimension 1/second for both. but the value will not be the same.