Vertical perturbation velocity () is a term used in aerodynamics to describe the component of the velocity perturbation that is oriented vertically, perpendicular to the direction of the freestream flow. It represents the change in vertical velocity caused by aerodynamic disturbances or perturbations in the flow around an object, such as an aircraft wing.
NOTE: For small perturbations, 𝜃 is small. Hence, tan 𝜃 ≈ 𝜃
- is the vertical perturbation velocity, which describes the vertical component of the velocity perturbation caused by aerodynamic effects. It is typically perpendicular to the freestream flow.
- is the freestream velocity, representing the constant velocity of the fluid (e.g., air) in the freestream, unaffected by perturbations. It is measured in meters per second (m/s).
- is the angle that represents the orientation or inclination of the perturbation relative to the horizontal direction. It is typically measured in radians (rad).