In fluid dynamics, Lamb vector is the cross product of vorticity vector and velocity vector of the flow field, named after the physicist Horace Lamb.
It appears in the Navier–Stokes equations through the material derivative term, specifically via convective acceleration term, In irrotational flows, the Lamb vector is zero, so does in Beltrami flows.
The concept of Lamb vector is widely used in turbulent flows.
The Lamb vector is analogous to electric field, when the Navier–Stokes equation is compared with Maxwell's equations.
The Euler equations written in terms of the Lamb vector is referred to as the Gromeka–Lamb equation, named after Ippolit S. Gromeka and Horace Lamb.
, the Lamb vector divergence reduces to where In regions where