Study on radar scattering characteristics of double S-shaped nozzles with different aspect ratio

Abstract

To study the radar scattering characteristics of dual S-bend nozzles with different exit aspect ratios, the iterative physical optic method (IPO) method and equivalent edge currents method (EEC) method were combined to build a code that can be used to solve the electromagnetic scattering field of the nozzle. The reliability of the method has been verified by comparing the reference data. Then, the forward and back-forward IPO and ray tracing methods are used to reduce the calculation time. CFD method is used to calculate and analyse the influence of aspect ratio double S-shaped nozzle on aerodynamic performance. The thrust coefficient and the total pressure recovery coefficient of the double S-shaped nozzle will gradually decrease with the increase of the aspect ratio. the influence of the aspect ratio on the radar scattering characteristics of the dual S-shaped nozzle under the C-band was simulated by the IPO and the results were discussed.it is obtained that the RCS average value in the range of −40°~40° gradually decreases with the increase of the aspect ratio. Under the vertical polarization mode of the pitch detection plane, the average RCS of the AR6 model is 52.8% lower than that of the AR3 model, while it is reduced by 11.0% in the horizontal polarization mode, which has better stealth performance.