低騒音風洞計測部暗騒音の研究 : 第1報,計測部暗騒音の音源分析

概要

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Low-noise acoustic wind tunnels which have quieter air flow are important for development of quiet and agreeable vehicles and air-conditioning systems. Even in low-noise wind tunnel Where noise from the air-source fans has been almost entirely eliminated, there are still a number of aerodynamic noise sources around the measuring section. These aerodynamic noise sources include : (a) boundary layer on nozzle surface, (b) releasing vortices from nozzle edge, (c) jet flow, (d)friction of air with the floor, (e) control equipment for boundary layer, (f) boundary layer on bell mouth surface and (g) boundary layer on diffuser surface. The analysis of these sound contributions to the noise level has been carried out by model experiments and using empirical data obtained with a small blow-down type wind tunnel and a large-scale flow-rounding wind tunnel. As a result, it is found that the dominant aerodynamic noises are the sound from control equipment for the boundary layer, the friction of air with the floor, and the boundary layer on the diffuser surface.
一般社団法人日本機械学会の論文
1995-10-25