I don't get streamlines as an option when I use a 3D model. It works fine with the 2D model.

The stream function is only defined in 2 d flows.

The stream function is only defined in 2 d flows, in 3d you have pathlines.

When dealing with 3D probelms, people usually use the "path lines" under the "define" option to visulize the flow fields because the streamfunction defined in 3D space is a vector and can't be visulized as it's in 2D region.

The streamlines are the locus of the tangent of teh Velocity vector. They usually defined using the potential function which is derived using 2d analysis. So, if You want to define them in 3d problem, You have to define the planer streamlines in the three Planes (x-y, y-z and z-x) and then add them victorially. You get then the locus of the thengent of spatial (whole) velocity vector. The path lines are the pathes which the Fluid particle take during flowing in the Domain.

[MDinc]

Murat
I also have same problem. I tried pathlines to see the flow trajectory but regarding the huge number of elements in domain, computer gets stuck and then I reboot it. How can I create streamline in 3D, how can I create three plane and add them to see the tangent velocity vectors?

Thanks,
Murat