inertial flow

(fluid mechanics) Flow in which no external forces are exerted on a fluid.
(geophysics) Frictionless flow in a geopotential surface in which there is no pressure gradient; the centrifugal and Coriolis accelerations must therefore be equal and opposite, and the constant inertial wind speed V_i is given by V_i = fR, where f is the Coriolis parameter and R the radius of curvature of the path.