Harmonic generation in the fields of disc radiators

An experimental and theoretical program investigating the generation of harmonics within the fields of disc radiators driven at a single frequency at finite amplitudes is described. A hydrophone, scanned under computer control, was used to record spatial pressure-amplitude variations within the fields of disc-shaped piezoelectric transducers radiating into a water bath. The instrumentation system digitized the waveform at each point and estimated the amplitude of the fundamental frequency and the next three harmonics at 893 kHz. The results are compared to theoretical predictions based on a quasilinear approach and using the concept of plane and edge waves radiated from the disk transducer. It is shown that theory and experiment agree reasonably well for a transducer that approximates to a plane piston