Twisting term
From Glossary of Meteorology
twisting term
(Also called tilting term, tipping term.) The term in the vorticity equation that represents the generation of vertical vorticity by the twisting of horizontal vorticity into the vertical through the agency of shear in the vertical velocity.
In symbols this term is where u, v, and w are the velocity components along the coordinate directions x, y, and z, respectively.
