The impact of geometrical parameters on hydrodynamic noise generation

Measurement of the acoustical characteristics of throttling valves, particularly in water installation systems, is usually based on airborne measurements. However, direct measurements of fluid-borne noise give us a better understanding of noise-source acoustical characteristics. This method allows us to use the determined noise-source characteristics to create hydroacoustical models describing the relationship between hydraulic and acoustic conditions. This method also shows the influence of geometrical parameters on noise production and emission. The influence of the diameter and length of a simplified throttling device on its acoustical characteristics was experimentally analysed. This analysis showed how the chosen geometric parameters influence noise production. Simple dimensional analysis enables derivation of the hydroacoustic scaling laws for the dominant noise sources. The experimental results further proved the influence of geometrical parameters on acoustical characteristics. This influence was determined using non-linear multiple regression analysis on the experimental data. Among other characteristics, the impact of the combined geometrical parameter called “slimness” on the sound generation mechanism is also experimentally determined.