Large eddy simulation (LES) and Ffowcs Williams-Hawkings (FW-H) equation were used to investigate the spectral characteristics of the rod-airfoil interaction noise and the influence of the quadrupole source. The flow field prediction was in good agreement with experiment data

and the spectral shape of the acoustic radiation was consistent with experiment results. The front 30% chord length at the leading edge of the airfoil is the main interaction noise source. For the reason of the different span-wise length between simulation and experiment

a new group of formulas was derived based on the hypothesis of trigonometric correction function and the results were compared with the rectangular

exponential and Gaussian functions. The correction deviation for different correction methods is as large as 7.6 dB. The correction effect of the trigonometric function is similar to the rectangular function and better than Gaussian function

whilst the exponential function has the poorest correction effect. Solid wall surfaces and permeable data surfaces were used for acoustic calculation to investigate the effect of quadrupole source. The results show that the impact of quadrupole source is negligible at low Mach number.