Streamlines under Moving reference frame; Spiral streamline from Tecplot
Hi,
I plot streamlines based on velocity field for a rising bubble using Tecplot and my own program. In Tecplot, I got SPIRIAL streamlines inside bubble, which should be closed streamlines (closed loops). I found a similar discussion posted before in this forum but was not given a solution (http://www.cfdonline.com/Forums/mai...treamline.html). I also calculated stream function in my own program. However, the plot of streamlines (contour plot) looks like the streamlines in Stationary reference frame. I use Moving reference frame (which is attached to the rising bubble). I did correct boundary conditions for stream function corresponding to Moving reference frame. Should I correct the governing equation (vorticity) too? (It is related to the derivative of zvelocity which should not be affected by adding a constant or not). I appreciate any idea.:) 
Check that the stream function calculated in your own program gives you the correct streamlines when there is no bubble, i.e., the streamlines of a uniform flow at the negative of the bubble velocity. Then keep in mind that while the vorticity (being a derivative of the velocity) is unaffected by adding a constant to the velocity, the stream function on the other hand (being an integral of the velocity) is indeed changed by adding a constant to the velocity.

Thanks a lot for your timely help, Ananda. I will give a try about what you said. 
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