## trajectory

(

*Or*path.) A curve in space tracing the points successively occupied by a particle in motion.At any given instant the velocity vector of the particle is tangent to the trajectory. In steady- state flow, the trajectories and streamlines of the fluid parcels are identical. Otherwise, the curvature of the trajectory where

*K*_{T}is related to the curvature of the streamline*K*_{S}by*V*is the parcel speed and ∂ψ/∂*t*is the local change of the wind direction. The curvatures and wind change are positive for the cyclonic sense of flow.