Simulation of Flow Field around a Generic Helicopter Fuselage by Modeling the Rotor

In this research, the steady-state flow filed around a 3D body and rotor configuration of the ROBIN helicopter is simulated. The rotor is modeled by an actuator disk. For this purpose, an annular computational domain replaces the rotor and some modeled source terms are added to the momentum equations. This modeling of rotor considerably speed up computational time. The flow field over this helicopter fuselage is simulated for six cases of different advance ratios and thrust coefficients. The accuracy of using uniform, linear and BET distributions for the rotor in the source term is investigated. With the BET and some corrections to pitch angles, pressure coefficients and variation of thrust and power of rotor are predicted in agreement with experimental data. For the nominal thrust coefficient of 0.06, different loading methods on rotor using experimental results are compared for two advance ratio of 0.05 and 0.23. In the advance ratio of 0.23 for the upper surface of helicopter, no considerable difference among the different employed methods is observed. However, for the advance ratio of 0.05 and for the side that helicopter blades get closer to the body (Starboard side), the results with the modified methods are better than BET method. The presence of strut in the computational domain has important effects in high speeds and causes reduction of pressure coefficients over body especially in downstream of the strut.