Vorticity transport in solidification boundary layers

A solidification boundary layer, where vorticity is concentrated, is shown to scale as delta similar to (nu /V) sin theta where theta is the angle tha t the solidification front makes with the oncoming flow, nu is the kinemati c viscosity of the melt, and V is the solidification rate. Key similarities with the suction boundary layer are outlined. Transport of vorticity, by d iffusion and advection, in flows that solidify is discussed in the context of the planar-flow spin casting process, with special attention paid to how vorticity leaves the how. Direct experimental evidence for a solidificatio n layer in that application is reported.