Reduction of interaction noise using grooved cylinder and wavy leading edge airfoil

The grooved and the wavy leading edge structures have been designed to reduce the interaction noise generated by the cylinder-airfoil model. The wind tunnel tests conducted at different incoming velocities ranging from 40 to 60 m/s, revealing that the wavy leading edge structure only exhibits a noise reduction effect within the mid-frequency band (800 similar to 4000 Hz). However, the combination of the two structures compensates for the insensitivity to low-frequency peak noise. At the velocity of 60 m/s, there are reductions of 14.7 dB for peak noise and 5.4 dB for average noise within the mid-frequency band. Numerical simulations based on large eddy simulation and the Ffowcs Williams-Hawkings acoustic analogy are performed to further explore the mechanisms of noise reduction. The results indicate that integrating the two structures has a substantial impact on reducing the pulsation pressure and enhancing the decorrelation and decoherence effects among the noise sources. The strong phase interference effect leads to a decrease in the radiation efficiency of the interaction noise.