Could anyone give me a definition of Richardson no. , I think its someting to do with density gradients I think, and how does it arise in swirling flows if the flowfield is incompressible. Thanks for the help.

Philip

Dear Philip

There are severalm, but entirely different, Richardson number in fluid mechanics.

For mixed convection, Richardson number is defined as

Ri = Gr / Re**2

Where, Gr = Grashof #, Re = Reynolds #

For swirling flow, gradient Richardson numberis the ratio of body force(centrifugal force) to the inertial force, and defined as,

Ri = [(k/epsilon)**2]*[U/R**2]*[partial(UR)/partial(R).

Where, U = vel. in the streamwise direction and R = local radius of curvature.

And you may find similar definition for Richardson number for swirling flow.

Sincerely, Jinwook