An Etymological Dictionary of Astronomy and Astrophysics
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In fluid mechanics, a quantity that describes helical flow. It is defined by the integrated scalar product of the velocity field and the → vorticity: K_K = ∫ dVu . (∇ x u). In the absence of magnetic field, this quantity is conserved by the → Euler equation. See also → magnetic helicity.

→ kinetic; → helicity.