2007 年 73 巻 732 号 p. 1629-1636
The purpose of this investigation is to clarify the effects of turbulence on aerodynamic noise generation. In order to estimate aerodynamic noise radiated from automobiles and high speed trains in turbulent flow fields, a low-noise turbulence generator for small wind tunnel was developed. The developed generator makes a large turbulent field which has inertial subrange in energy spectrum of turbulence. The noise level of the generator was sufficiently small to estimate the aerodynamic noise from the model of autombiles and high-speed trains. The experimental result showed that unsteady sound was generated by the incoming flow turbulence. And noise levels depend on the scale of turbulence. These results indicated that the active turbulence generator is useful for estimating the aerodynamic noise from automobiles in turbulent flow fields.