Keerisvoog on vedeliku voog, milles vedeliku osakeste kiirus omab tangentsiaalset komponent telje ümber, mis koos vedeliku osakeste kiiruse aksiaalse komponendiga tekitab spiraalse voo.
A swirling flow is a fluid flow in which the fluid particles have a tangential component of velocity about an axis which, when combined with an axial component of velocity, produces a helical or spiral flow.