ASA 130th Meeting - St. Louis, MO - 1995 Nov 27 .. Dec 01

4pNSb5. Local algorithms for controlling an active piston damping system.

Vladimir V. Arabadzhi

Inst. of Appl. Phys., Russian Acad. of Sci., Dept. of Hydrophys. and Hydroacoust., 603600 Nizhny Novgorod, Russia

A scattering and/or emitting surface with local (of small wave dimensions) piston emitters located directly on it is considered. The problem of active sound damping by the quantity of prior information on the wave field and surface properties are classified. It is shown that in some practically significant cases one may do without traditional accumulation in a damping system of the entire information ``imprint'' of the wave field. The aim of the paper is the construction of the most local algorithms. Four control algorithms are described in the paper: (a) the algorithm of the maximum of the total average for the period of the absorbed power on the pistons, (b) the algorithm of the iterative compensating of the sound pressure on pistons, (c) the algorithm of the compensating of the volume velocity, (d) the algorithm of the physical surface in accordance with the incident wave. The results of the action of algorithms (a)--(d) is the transformation of the distribution of normal oscillating velocities on a given surface to the region of high (weakly emitting) space frequencies. A joint solution of the problems of radiating and scattering damping is achieved too.