magnitude_and_direction_of_relative_velocity¶

Calculates the magnitude and direction of the relative velocity u_rel at a local section of the wing.

\[u_{rel, i}^G = \bar{U}_{\infty, i}^G - C^{GA}(\chi)(\dot{\eta}_i^A + v^A + \tilde{\omega}^A\eta_i^A\]

where \(\bar{U}_{\infty, i}^G\) is the average external velocity across all aerodynamic nodes at the relevant cross section.

param displacement: Unit vector in the direction of the free stream velocity expressed in A frame.
type displacement: np.array
param displacement_vel: Unit vector in the direction of the local chord expressed in A frame.
type displacement_vel: np.array
param for_vel: A frame of reference (FoR) velocity. Expressed in A FoR
type for_vel: np.array
param cga: Rotation vector from FoR G to FoR A
type cga: np.array
param uext: Background flow velocity on solid grid nodes
type uext: np.array
returns: u_rel, dir_u_rel expressed in the inertial, G frame.
rtype: tuple