experimental investigation of aerodynamic noise characteristics of tandem asymmetric airfoils across varied angles of attack

This paper experimentally investigates the aerodynamic noise characteristics of a tandem asymmetric airfoil-airfoil at different angles of attack in the 0.5 m×0.4 m acoustic wind tunnel at wenzhou university. based on the airfoil chord length and the wind speed, the reynolds number ranges between 2.2×105 and 3.5×105. meanwhile, the attack angle (α1 and α2) of both tandem airfoils varies between 0~20°, and the noise is measured using a far/near-field microphone array. the experimental results indicate that when the attack angle α1 of the upstream airfoil is small (α1<15°), its wake hardly interacts with the downstream airfoil, and the noise source is mainly concentrated at the trailing edge of the upstream airfoil. when the attack angle α1 is larger than 15°, the upstream wake interacts with the downstream airfoil, the noise radiates from the leading edge of the downstream airfoil, and the source location varies slightly at different frequencies. compared to the upstream attack angle α1, the downstream airfoil attack angle α2 has less impact on the aerodynamic noise of the tandem airfoils. additionally, the particle imaging velocimetry technique is employed to measure the flow field characteristics and analyze the mechanism of noise production.