• Journal of computational fluids engineering
• /
• v.14 no.1
• /
• pp.53-61
• /
• 2009

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 aero-acoustic analysis, CFD technique for aerodynamic analysis and Kirchhoff's method for the acoustic analysis were used. As for the optimization method, Kriging-based genetic algorithm(GA) model as a high-fidelity optimization method was chosen. Design variables and constraints are determined for arbitrary blade planform. The result shows that the optimized blade planform with high swept-back and taper ratio can reduce HSI noise by suppressing generation of the strong shock wave on blade surface and propagation of the noise to the farfield flow region.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.46 no.5
• /
• pp.376-384
• /
• 2018

The aerodynamic far-field noise was computed by an acoustic analogy code using the permeable surface for the UH-1H rotor blade in hover. The permeable surface surrounding the blade was constructed to include the thickness noise, the loading noise, and the flow noise generated from the shock waves and the tip vortices. The computation was performed with compressible three-dimensional Euler's equations and Navier-Stokes equations. The high speed impulsive noise was predicted and validated according to the permeable surface locations. It is confirmed that the noise source caused by shock waves generated on the blade surface is a dominant factor in the far-field noise prediction.