Reciprocity measurements in acoustical and mechano-acoustical systems. Review of theory and applications

摘要

Reciprocity is a property of all stable, linear, passive systems which contain only bilateral (reversible) elements. Flow may disturb reciprocity, but there are many cases in which the influence is so small that application of reciprocity is still acceptable. With the aid of reciprocal measurements, it is often possible to do experiments which are very difficult to perform in another way. Application of reciprocity measurements may also be advantageous because it may provide more accurate results than direct measurements. The reciprocal measurement techniques for the analysis of sound paths and for source characterization are well developed. The literature shows that these techniques are widely applied as tools in the development of quiet road vehicles and navy ships. There is also significant application related to the development of quiet aircraft and trains. For other areas of noise control the application is still rather small. Records on the use of electro-acoustical and electromechanical reciprocity are scarce. It seems that the possibilities of these are not yet fully recognised.