Abstract
Pile-fabrics are known to be useful for reducing aerodynamic noise. But it is not clear which parameters of pile-fabrics have large correlation with the amount of noise reduction. In this paper, it was examined experimentally and obtained results are as follows. (1) Flow resistance of pile-fabrics is an important parameter to reduce aerodynamic noise. The optimum pressure loss coefficient exists in rather small value. (2) The filling rate of piles has rather robust characteristics for reducing aerodynamic noise, but there are some optimum values of filling rate around 1%. (3) The noise reducing mechanism of pile fabrics is supposed to be clear.
