Exporting cell areas of a slice to compute flow rate


(Mark) #1

Hi all,

I have an openfoam simulation. I am interested in the flow though a slice, normal velocity vectors in this slice point in both directions.

Using the Integrating filter over the slice gives me the the average flow, but I am interested in the total flow in one direction and the total flow in the other direction. I plan to export the velocities and cell areas and do further calculations in python.

With the spreadsheet view I am able to compute the flow vectors for each point/cell. But I’ve not figured out how to include the area that is associated with the cell/point in the export so I can calculate the flow.

Is there a way to do this?

Thanks,


(Cory Quammen (Kitware)) #2

Add a Cell Size filter to the slice. The adds a cell data array with the areas of the cells to its output.


(Mark) #3

Thanks,

That did the trick


(Mark) #4

I am a bit confused on what the dimension of the presented variables is using the cell size filter.
since I want to compute a flow, and need the area of the cell I’m setting the attribute in spreadsheet-view to cell Data.
This provides me with a list of area’s and U:0 U:1 and U:2
I would have expected that if my defined plane is in the X-Z plane that I can compute the flow by using the Area of the cell multiplied by U:1, summing over the total area, however this does not add up to the flow I expect.

Is there something incorrect with my assumption?

Kind regards,

Mark


(Cory Quammen (Kitware)) #5

The Cell Size filter should give you the surface area of the cell in the units in which your data is defined. ParaView is agnostic to units of physical dimensions in your data. Is there some conversion needed for a point coordinate read in from the file to the physical size units you need to compute the derived quantity?