Blade planform optimization to reduce HSI noise of helicopter in hover

The objective of this research is to design blade planform to reduce high speed impulsive (HSI) noise from a non-lifting helicopter rotor using CFD method and optimization techniques. As for the aerodynamic part, CFD calculation is conducted to solve three dimensional unsteady Euler equations. As for the optimization method, sequential quadratic programming as a gradient optimization method and Kriging-based GA model as a non-gradient optimization method are used according to the different problem definition. Based on our previous research, objective functions, design variables and constraints are determined for arbitrary blade planform during optimization process. The result shows that the optimized blade planform can reduce HSI noise by supressing the strong shock wave from being generated on blade surface and being propagated to farfield flow region.