Horizontal perturbation velocity () is a term used in aerodynamics to describe the component of the velocity perturbation that is oriented horizontally, perpendicular to the direction of the freestream flow. It represents the change in horizontal velocity caused by aerodynamic disturbances or perturbations in the flow around an object, such as an aircraft wing.
- Horizontal perturbation velocity (û) in m/s
- Freestream velocity (V∞) in m/s
- Angle (θ) in rad
- Prandtl-Glauert factor (𝜆)