Hi I found an advantage of Schauberger Doppeldrall - double whirl in English.
The idea is that Taylor-Dean vortex creation is prevented by letting the Coriolis stress, that causes the buildup of Taylor-Dean vortices, act in different directions instead of consistently the same direction as is the case in unturned flow. Taylor-Dean vortices are the same as Görtler vortices. They are described in the plane perpendicular to the flow. A more general description is the Coriolis stress caused in bent flows. Dean vortices are mentioned as a lossy type of turbulence or drag in pipes and are mentioned in incompressible flow like water in pipes. Görtler vortices are usually mentioned in air with constraints like a plane wing. Image and link to laboratory example: https://physics.stackexchange.com/questions/725368/are-dean-vortices-creation-prevented-in-certain-flows-with-helicity Please also explain why the question was closed after one year. David
