Aerodynamic shape optimization of hovering rotor blades using a Non-Linear Frequency Domain approach

This paper presents a discrete adjoint-based aerodynamic optimization algorithm for helicopter rotor blades in hover using a Non-Linear Frequency Domain approach. The procedure to be used can be broken down into two phases: first, investigate and develop an accurate inviscid numerical model for the current generation of helicopter rotor blades; and second, demonstrate the approach for the redesign of a transonic Caradonna–Tung two-bladed rotor. The results in determining the optimum aerodynamic configurations require an objective function which minimizes the inviscid torque coefficient and maintains the desired thrust level at transonic conditions.

► Validated the Non-Linear Frequency Domain method for Rotorcraft Flows.
► Developed the Discrete Adjoint Equations for the Non-Linear Frequency Domain method.
► Demonstrated aerodynamic shape optimization to improve the performance of hovering rotor blades.