Questions overset interpolation with DyM very slow for large 3D cases

hxaxtma · November 29, 2017, 14:40

Hi guys,
At the moment I am playing around with the new overset feature of OF 1706+. Everything is fine so far, I observed just for large 3D cases and moving mesh cabalities (for example a flapping 3D airfoil) a huge decrease in speed up (overPimpleDyMFoam). This is due to the cutting hole algorithm of the overset analysis itself.

There are three kinds of interpolations possible:
inverseDistance
trackingInverseDistance
cellVolumWeight.

So which one would you recommend in order to speed up the cutting hole algorithm. Mesh is changing here every time. At the moment I am using inverseDistance approach by defining a searchBox with subsequent Divisions.

Thanks in advance,

Yann · December 29, 2017, 07:25

I'm working with overPimpleDyMFoam on a moving object in 3D meshes and I tried the 3 algorithms on the same case.

On my case, inverseDistance and trackingInverseDistance have pretty much the same speed, while cellVolumeWeight is way much longer (about 5 times longer than inverseDistance)

Those tests have been done only on one case so I'm not sure this results is valid as a general rule.

Furthermore, I used the default setup for the 3 algorithms.
For inverseDistance, I've seen it's possible to specify 3 parameters : layerRelax, searchBox and searchBoxDivisions.

How do you use the searchBox feature and did you notice a speed up with your setup compared to the default setup?

November 29, 2017, 14:40	Questions overset interpolation with DyM very slow for large 3D cases	#1
hxaxtma Senior Member Join Date: Jan 2014 Posts: 175 Rep Power: 9	Hi guys, At the moment I am playing around with the new overset feature of OF 1706+. Everything is fine so far, I observed just for large 3D cases and moving mesh cabalities (for example a flapping 3D airfoil) a huge decrease in speed up (overPimpleDyMFoam). This is due to the cutting hole algorithm of the overset analysis itself. There are three kinds of interpolations possible: inverseDistance trackingInverseDistance cellVolumWeight. So which one would you recommend in order to speed up the cutting hole algorithm. Mesh is changing here every time. At the moment I am using inverseDistance approach by defining a searchBox with subsequent Divisions. Thanks in advance, bennn, christoph45 and Ansh like this.

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December 29, 2017, 07:25		#2
Yann Senior Member Yann Join Date: Apr 2012 Location: France Posts: 186 Rep Power: 12	I'm working with overPimpleDyMFoam on a moving object in 3D meshes and I tried the 3 algorithms on the same case. On my case, inverseDistance and trackingInverseDistance have pretty much the same speed, while cellVolumeWeight is way much longer (about 5 times longer than inverseDistance) Those tests have been done only on one case so I'm not sure this results is valid as a general rule. Furthermore, I used the default setup for the 3 algorithms. For inverseDistance, I've seen it's possible to specify 3 parameters : layerRelax, searchBox and searchBoxDivisions. How do you use the searchBox feature and did you notice a speed up with your setup compared to the default setup?