Local rotation rate of a fluid element; ω = ∇×v. Evolves via the vorticity equation; vortex lines are advected with the flow in barotropic inviscid flow (Helmholtz/Kelvin).
Local rotation rate of a fluid element; ω = ∇×v. Evolves via the vorticity equation; vortex lines are advected with the flow in barotropic inviscid flow (Helmholtz/Kelvin).