Abstract: In this study, wind tunnel experiments were conducted to investigate and analyze the far-field noise of polygonal cylinders within a Reynolds number range of 20 to 80 thousand. Two conditions were selected: flow incidence on corner or face, considering the influence of angle of attack. The study analyzed the characteristics of the PSD (pow-er spectral density) of far-field noise, OASPL (overall sound pressure level) and the potential for noise reduction compared to a circular cylinder. The results indicate that the majority of the polygonal cylinders flow spectra is domi-nated by a pure tone. The OASPL conforms to the velocity sixth-power law based on the dipole source analogy. However, the sixteen-sided cylinder deviates from this law in high Reynolds number, suggesting the influence of transition. The triangular and square cylinder show some noise reduction effects under corner orientation flow, while the five-sided cylinder exhibits noise reduction effects under face orientation flow.

Key words: polygonal cylinder, aerodynamic noise, circular cylinder, dipole source, wind tunnel