ANALYSIS OF LOW FREQUENCY RADIATION CHARACTERISTICS OF A FINITE CYLINDRICAL SHELL BASED ON VIBRATION AND RADIATION MODES

By means of the modal expansion approach, the coupled vibration and sound wave equation for a finite cylindrical shell is solved. The expressions of the radiated sound power and the radial squared velocity are investigated. By use of the solution of the equation, the contribution of the low order vibration modes to the radial squared velocity and the radiated sound power is discussed in different fluids. Then, the sound radiation for the finite cylindrical shells is investigated based on sound radiation modes at low frequencies in different fluids. The results show that more vibration modes contribute to the sound power of the finite cylindrical shells in air, so more sound radiation modes are required to calculate the sound power. However, in water, the influence of the fluid-structure coupling on the radial squared velocity of the shells is very remarkable, the performance of the sound power radiated from the finite cylindrical shells is decreased with the increase of the circumferential vibration modes, and only first several sound radiation modes are required to accurately calculate the sound power.