The flow field and performance of a helicopter ducted tail rotor in hovering and sideward flight were analyzed using CFD(Computational Fluid Dynamic) technique.At first the general governing equations of turbulent flow around ducted tail rotors were set up

and then directly solved by finite volume approach and SIMPLE(Semi-Implicit Method for Pressure-Linked Equations) approach in an axisymmetric coordinate system.The spinning fan was represented as time-averaged momentum source terms distributed along the span of the fan with functional relationship to the local flow conditions in N-S equations.The calculation method also included a stair-step representation of the shroud

staggered grid system

the k-ε turbulence model and wall function method on the shroud.The calculated results of flow field and performance correlation show good agreement with the measured data.Therefore

it is concluded that the numerical simulation technique is proved to be feasible for analyzing design issues of ducted tail rotor.