Acoustic and radar integrated stealth design for ducted tail rotor based on comprehensive optimization method

For the integrated stealth issue of ducted tail rotor noise radiation and radar scattering, a comprehensive optimization method based on high frequency electromagnetic calculation theory and boundary element method is introduced. The radar cross section of the rotor, radiated noise and radar cross section of the ducted tail rotor are designed as optimization goals under the constraints of geometric parameters and aerodynamic force. The model of the ducted tail rotor is established by using the full factorial design and the flow field is constructed by high-precision unstructured grid technology. The aerodynamic characteristics of the ducted tail rotor is simulated by the computational fluid dynamics method based on Navier–Stokes equations and k–ε standard viscous model. The noise radiation is solved by boundary element method and the radar cross section value is calculated by physical optics method and physical theory of diffraction. On the basis of these calculation results, the optimization model of the ducted tail rotor is obtained and generated by comprehensive optimization method based on Pareto solution. The final scheme has been satisfactorily improved in terms of noise suppression, radar cross section reduction and aerodynamic lifting. The proposed approach is very effective and efficient for the acoustic/radar comprehensive stealth design of the ducted tail rotor.