[zebG]

By my understanding, from what I was taught at uni, Reynolds numbers are defined for a given shape or locally (ie. for each cell in a mesh). I've never seen Reynolds Numbers calculated for each streamline; is there any reason why this is not possible in theory?

The reason I ask is that I'm looking at a rotating disc with a hollow core and am attempting to work out if a turbulent layer trip device would lower drag. As the disc is rotating, the streamlines are not obvious.

I've managed to plot the following expression on the surface:

density*local velocity/ dynamic viscosity

I've also got streamlines displayed on the surface to give the length term.

Is the only method of calculating Reynolds Number to manually measure the surface streamlines and multiply this by the locally plotted expression from above or is there a chord term I can use in equations?