RADIATION INSTABILITY OF A PURE-TONE SOURCE MOVING ON A FLOATING PLATE

The two-dimensional problem on the radiation of a pure tone source mov ing steadily on a floating elastic plate is considered. it is shown th at, in the presence of compressive forces applied to the plate, some c ombinations of the speed of motion and the natural frequency of the so urce correspond to conditions, at which the power arriving at the sour ce because of the anomalous Doppler effect can compensate for the radi ation loss due to the normal Doppler effect. As a result, a radiation instability develops, which may cause the fracture of the plate. It is suggested that the radiation instability is responsible for the gener ation of narrow-band oscillations observed in the full-scale studies o f atmospheric fronts passing over compressed ice fields.