ACTIVE SOUND POWER REDUCTION BASED ON MUTUAL RADIATION IMPEDANCE EFFECT BETWEEN TRANSDUCERS IN WATER

The output sound power of a primary transducer (corresponding to a noise source) iii water can be reduced by arranging an array of controllable secondary transducers. The mutual radiation impedance method is used to evaluate the total output power from the primary and secondary transducers. The output power is calculated from a quadratic function of the velocity of the active area of the secondary transducer. For various arrangements of the primary and secondary transducers, the quadratic equations are derived in terms of the velocity of the active area of the secondary transducer. If the two transducers are spaced less than one half-wavelength apart in water and are 180-degrees out of phase, the best reduction iii total output power can be achieved at the optimum velocity of the active area of the secondary transducer.