USE OF A NAVIER-STOKES CODE IN UNDERSTANDING TILTROTOR FLOWFIELDS IN HOVER

Three-dimensinal Navier-Stokes flow calculations applied to a tiltroto r in hover for a no wind condition are examined. The results of the co mputations focus on the quantification of the fountain flow region abo ve the wing and fuselage center section (all components of velocity), radial and azimuthal variation of rotor loads. This paper presents 3-D Navier-Stokes computations of the fountain flowfield using, (i) a two rotor configuration, (ii) a single rotor configuration with a wing, i mage plane, and ground plane, and (iii) a completely isolated rotor. T he image and ground plane is modelled as a viscous wall. The three-dim ensional code uses time-averaged momentum source terms in the momentum equations and solves the steady, incompressible, laminar Navier-Stoke s equations, in a non-body-fitted three-dimensional Cartesian coordina te system. This approach makes the code an ideal design tool for compl ex problems. The results compare how well a semi-span model with a sin gle rotor and image plane predicts the result of the full spare config uration with dual rotors. The 3-D Navier-Stokes computations are compa red with previous test data.