High-fidelity numerical analysis and optimisation of ducted propeller aerodynamics and acoustics

This paper presents numerical analyses of aerodynamics and aeroacoustics of ducted/un-ducted propellers based on high-fidelity CFD methods, and adjoint-based aerodynamic performance optimisation of the ducted propeller by altering the duct and blade shapes. Ducted propeller experiments by NASA are chosen for validation and used as baseline designs. High-fidelity CFD simulations are performed using the in-house solver HMB3. The aeroacoustics is analysed using the CFD solutions and in-house codes based on FW-H equations. The aerodynamic and near-/far-field acoustic benefits by ducting are shown quantitatively. An adjoint-based aerodynamic optimisation framework is also applied to the ducted propeller by altering the duct shape and the blade twist distribution. The optimisation shows improved performance for the ducted propeller over the initial design, especially at higher blade pitch. The far-field acoustic benefits of the optimised designs are also examined and are maintained after the optimisation