METHOD FOR KNOWING SOUND PRESSURE IN THREE-DIMENSIONAL SOUND FIELD

摘要

PURPOSE:To efficiently perform calculation, by dividing a linear sound source having a cross-sectional dimension smaller than the wavelength of sound into cylindrical elements having almost linear vibration speed distribution when the sound pressure of a three-dimensional sound field is calculated by a boundary element method to calculate the sound pressure by operation and integration. CONSTITUTION:Each of cylindrical elements 1 is a vibrating rigid cylinder having a finite length being a linear sound source having a cross-sectional dimension smaller than the wavelength of sound and capable of neglecting the scattering of sound. For example, the piping 3 connected to the compressor of a refrigerator is divided into elements having almost linear vibration speed distribution by surfaces S1, S2... to form a plurality of the cylindrical elements 1. Complex vibration vectors V1a, V1b and V2a, V2b in known arbitrary directions are applied to both ends of 1a, 1b of each cylindrical element 1. The scattering of the sound from the cylindrical element 1 is neglected to calculate the surface vibration speed of the cylindrical element 1. This vibration speed is integrated over each section of the piping 3 to calculate the sound pressure of a three-dimensional sound field. By this method, the sound field is efficiently calculated and accuracy is enhanced.