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How to calculate gradient of pressure and velocity on an outlet face

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Old   December 5, 2008, 21:15
Default Hi All, I need to find the
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Senthil Kabilan
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Hi All,

I need to find the gradient of normal velocity (averaged over the outlet surface) along the direction normal to the outlets and also the gradient of pressure (once again an average) along the direction normal to the outlets.

Thanks in advance!
Senthil
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Old   December 8, 2008, 05:41
Default Maybe you can use the "sample"
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Wolfgang Heydlauff
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Maybe you can use the "sample"-Tool.

go look at http://www.cfd-online.com/OpenFOAM_D...s/1/10206.html

insteat of the points-"cloud" you also can use the "uniform" command which creates a line with variable number of points.
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Old   December 8, 2008, 18:26
Default Hi Wolfgang, Thanks for the
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Senthil Kabilan
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Hi Wolfgang,

Thanks for the Help. Actually, I wanted to calculate the both the gradients on the fly (i.e., after every iteration). I was using the buildGlobalBoundaryList.H computeMassFlux.H files to compute the massflux at the boundaries in my icoFoam. I used the following two lines to calculate the maximum gradient of velocity and pressure along the normal direction.

max_vel_grad= max(mag(U.boundaryField()[patchIndex].snGrad()));
max_press_grad=max(p.boundaryField()[patchIndex].snGrad());

Let me know if it is doing other than what I think it is doing!

Thanks in advance!
Senthil
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