The Theory and Experiment of Parametric Amplification of Three-wave Nonlinear Interaction in Water

The theoretical and experimental research on energy changes due to nonlinear wave interactions is presented. The physical principle of wave parametric amplification underwater was analyzed from the view of external force acting. The acoustic amplitude solutions to nonlinear wave interactions were given according to Burgers equation by imitating a three-wave interaction model. The process of the sound energy transfer was simulated and the results demonstrated that sound energy presented a tendency of pulsation variation, either to increase or to decrease. The experimental results of wave energy amplification were given under the condition of wave optimum coupling. Results of the theoretical and experimental research provide a technical guidance for analysis of sound energy changes during nonlinear wave interactions underwater, which shows the feasibility of detecting underwater weak signals through three-wave coupling.