Imposing PIV (2D) experimental data at turbulentDFSEMInlet for LES
I have 2D planar PIV data available from experiments (velocity field, Reynolds stresses and length scale information) and want to impose those at the inlet of the domain for the turbulentDFSEMInlet boundary condition.
Naturally, the PIV data - recorded at coordinates y and z (for the sake of argument here) - does not coincide with the coordinates y and z of the mesh at the inlet. Is there some functionality that can take the experimental data and y and z coordinates, interpolate the values onto the mesh and then write the required boundaryData file as an output within the constant/boundaryData/U/0/ directory? |
mapFields utility
see https://www.openfoam.com/documentati...mapFields.html including tutorials and Section A.2 of https://openfoam.com/documentation/u...-utilities.php for broader scope |
yes, I am aware of mapFields and how to use it to map solutions information from one simulation onto another, but I have experimental data in a non Openfoam format available (i.e. x, y and corresponding experimental value). The questing would then, probably, rather be, how do I get my experimental data into a form mapFields can understand?
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Aha.
Your measured data is a scalar field on 2D planar grid, correct? Does is suffice to write measurement locations as a (quadrilateral?) mesh and the measured data as a scalar field on there mesh? |
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Not sure. Should study tutorials myself.
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turned out to be actually not that difficult, i did some more digging and came up with the following (in case someone finds this in the future):
We need to provide a 1D list / array of data for the velocity U, reynolds stresses R and an integral length scale L. Then, we create 4 files in these locations (assuming we are currently in the root directry of the case, i.e. where we have the 0, constant and system directory): constant/boundaryData/points constant/boundaryData/<inlet-patch-name>/0/U constant/boundaryData/<inlet-patch-name>/0/R constant/boundaryData/<inlet-patch-name>/0/L where we need to insert the name of the inlet patch name here for <inlet-patch-name>. For example, if our inlet is called "velocityInlet", then the U file would be located at constant/boundaryData/velocityInlet/0/U. All files follow the same syntax and only the data entries are different for scalars, vectors and tensors: Code:
// scalar data Code:
// vector data Code:
// tensor data As an example, the points file could look like this (assuming data is only available at the inlet along a 1D line in the y direction): Code:
( Code:
velocityInlet By providing the data in the constant/boundaryData folder for the physical quantities, it also seems that the simulation does stall (as described here), though there still seems to be an issue with the velocity magnitude, but I did not have time as of now to investigate that further. |
Thanks a lot for the solution!
How do you obtain length scale information from PIV? Do you assume a constant value throughout the field? |
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