Sampling along a radius

djh2 · March 12, 2014, 17:20

Hello, I'm in the process of working through some data from an LES case that I'm studying. The experimental results are given as time-averaged data, given at a specified radius.

I'm looking to sample my time-averaged field data at this radius, but I'm not sure what the best method for averaging those values around the radius.

My plan was to use the sample utility to obtain N points along a curve (a circle of radius r, defined by their (x y z) coordinates. Then I can manually average this in post-post-processing pretty easily.

I have about 8 radii distances to sample at about 5 z locations.

I know that I can obtain a circle in ParaView by intersecting a sphere with a slice, I read that on these forums. Since there are many points and averages to obtain, and since I'd like to modify the simulation and test for improvement, you can understand this is not the preferred method.

I know there are a lot of functions and features to OpenFOAM (I've been struggling to put together a custom boundary condition for a few days now). I have done some work with the code, so I'm not afraid to put together a utility if needed. If someone could point me in the right direction on this, it would be much appreciated.

james.conger · March 19, 2014, 20:15

I use the sample utility and then post process the output using Python to compute the averages. Simple and easy to automate.

djh2 · March 25, 2014, 11:26

I am considering several methods of averaging about a radius to transform results from (x,y,z) to (r,z) coordinates.

I have been able to average the sample output, which will work for a discrete radius of sampled points; however I am trying to consider a more robust solution that is more of a core utility than a basic text file post processor.

Does anyone have some ideas on how this could be done? I like that the "sample" utility will interpolate points. My advisor suggested averaging points that fall within a tolerance, such as r = 5 +/ 0.001.

I'm trying to consider a variety of options, but I think the "best" implementation would be extending the sample utility.

March 12, 2014, 17:20	Sampling along a radius	#1
djh2 New Member David H. Join Date: Oct 2013 Posts: 25 Rep Power: 13	Hello, I'm in the process of working through some data from an LES case that I'm studying. The experimental results are given as time-averaged data, given at a specified radius. I'm looking to sample my time-averaged field data at this radius, but I'm not sure what the best method for averaging those values around the radius. My plan was to use the sample utility to obtain N points along a curve (a circle of radius r, defined by their (x y z) coordinates. Then I can manually average this in post-post-processing pretty easily. I have about 8 radii distances to sample at about 5 z locations. I know that I can obtain a circle in ParaView by intersecting a sphere with a slice, I read that on these forums. Since there are many points and averages to obtain, and since I'd like to modify the simulation and test for improvement, you can understand this is not the preferred method. I know there are a lot of functions and features to OpenFOAM (I've been struggling to put together a custom boundary condition for a few days now). I have done some work with the code, so I'm not afraid to put together a utility if needed. If someone could point me in the right direction on this, it would be much appreciated.

March 19, 2014, 20:15	sampling	#2
james.conger New Member Jim Conger Join Date: Jan 2014 Location: California, USA Posts: 21 Rep Power: 12	I use the sample utility and then post process the output using Python to compute the averages. Simple and easy to automate.

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March 25, 2014, 11:26		#3
djh2 New Member David H. Join Date: Oct 2013 Posts: 25 Rep Power: 13	I am considering several methods of averaging about a radius to transform results from (x,y,z) to (r,z) coordinates. I have been able to average the sample output, which will work for a discrete radius of sampled points; however I am trying to consider a more robust solution that is more of a core utility than a basic text file post processor. Does anyone have some ideas on how this could be done? I like that the "sample" utility will interpolate points. My advisor suggested averaging points that fall within a tolerance, such as r = 5 +/ 0.001. I'm trying to consider a variety of options, but I think the "best" implementation would be extending the sample utility.