[dkxls]

Can somebody explain me why the droplet distortion parameter 'y' is limited to positive values in the TAB oscillation equation?
This is done in the lagrangianSpray (2.2.x) [1] and dieselSpray (2.0.x) [2] library.

To my understanding y=0 corresponds to spherical droplet, a positive deformation flattens the droplet perpendicular to the flight directions (y>0) and a negative deformation elongates the droplet (y<0) in flight direction.

I do understand the implications concerning the distorted sphere model due to Liu (1993), i.e. 0<y<1, but this doesn't explain why the distortion parameters y and yDot are set to 0.0 as soon as y is negative.

I would be happy about any comment/explanation on this issue.

-Armin



Here the links to the source code
[1] https://github.com/OpenFOAM/OpenFOAM...yParcel.C#L419
[2] https://github.com/OpenFOAM/OpenFOAM...upModel.C#L121

References:
Liu, A.B.; Mather, D.; Reitz, R.D., "Effects of Drop Drag and Breakup on Fuel Sprays," SAE Paper 930072, SAE Transactions, Vol. 102, Section 3, Journal of Engines, pp. 63-95, 1993

[dkxls]

I reported a bug on this issue:
http://www.openfoam.org/mantisbt/view.php?id=1018

If somebody would still have a comment/explanation, please also write it to the bug tracker.