Characterization of the effect of helicopter isolated blade vortex on dynamic stall

In this research, the dynamic stall of sections near the rotor blade tip at a maximum cruise speed of the helicopter with an advanced ratio of 0.35 and cyclic pitching motion, has been studied by using CFD simulation. the URANS equations are solved using the finite volume discretization method. Also, the mesh used is of the hybrid type and the k-ω SST model is used to model the turbulent flow. numerical simulation validation is performed using the results of AH1-G helicopter flight tests, which indicates the effectiveness of results. The results indicate that the shock wave causes dynamic stall in the region of the advancing side and The effects of shock wave on the lift coefficients in the areas closer to the blade tip are weakened due to tip vortex penetration and the changes in the lift coefficients are less and more uniform than the inner areas of the blade. the ratio of lift coefficient changes to the maximum of this coefficient in the areas closer to the blade tip is reduced by 10.2%. the results of this study show that despite the formation of the LEV in the innermost areas of the blade severe dynamic stall does not occur in the retreating side, which is caused by the presence of radial flow due to the rotation of the rotor blade, which weakens the LEV.