RESEARCH ON CHARACTERISTICS OF SOUND RADIATION IN WATER FROM STIFFENED CYLINDRICAL SHELLS EXCITED BY INTERIOR SOURCE: Ⅱ. EXAMPLES

摘要

Based on sound radiation theory of submerged stiffened cylindrical shells excited by interior source, a finite stiffened shell is numerically studied in the present paper. The interior mean quadratic sound pressure level, the radiated sound power level and the mean quadratic velocity level are calculated. The effect of cavity-shell coupling on underwater sound radiation from the shell excited by an interior harmonic point source is analyzed; the effect of the point source’s radial position and axial position in sound cavity on sound radiation from cylindrical shell is discussed; the sound radiation characteristics of a shell excited by two point sources with different phases are discussed. After calculation and analysis, the following conclusions can be obtained: The coupling of sound cavity and shell has little effect on shell’s vibration, interior sound field and sound radiation characteristics when the shell is full of air; change of point source’s position has little effect on radiated power, however, radial position has greater effect on mean quadratic velocity and interior mean quadratic sound pressure than axial position; the nearer to shell surface the point source is, the higher the shell’s mean quadratic velocity is; two point sources radically symmetric with same or opposite phrases have little effect on shell’s sound radiation characteristics, while they will have great effect if they are symmetric about the midsection of the shell. This provides theoretical basis for calculating characteristics of vibration and sound radiation from stiffened cylindrical shell excited by interior sound sources more quickly and guidance for placement of interior sound sources.