Analysis And Evaluation For Transient Radiated Noise Of Underwater Targets

The steady-state radiation noise of underwater target is getting lower and lower resultfrom the development of vibration and noise reduction technology for structure-borne, thetransient radiation noise became the main exposure source of underwater targets. Comparedwith constant speed direct flights radiation noise, it is different in statistics and measurement,and attaches great importance to emphases of vibration noise reduction.In order to specialize in the relationship between transient radiation noise and itsacoustic analogy, take advantage of acoustic analogy of radiation noise and the result ofexperimental data processing with Improved Empirical Mode Decomposition (EMD). Baseupon cases study, giving advice to vibration and noise suppression of underwater target. Bycombining the feature of transient radiation noise and its acoustic analogy, evaluate the effectof vibration damping and noise reduction research.The mode mixing and aligning have impact on precision of instantaneous frequency andinstantaneous azimuth by the method of Energy Operator Separation algorithm (EOSA).Kriging play a significant role in inhibiting end disposal for lack of boundary information inEMD. In addition, put forward new that use Time-frequency entropy method as endingcondition, and shed light on the usage of intrinsic mode energy entropy in transient radiationtesting. To verify and examine the Improved EMD for radiation noise which produced by ballinto water, an experiment has been done in anechoic water tank in Harbin EngineeringUniversity and Songhua lake. According to acoustic analogy of transient radiation noiseduring the propeller going other side, time-frequency entropy, Intrinsic energy mode entropyand normalized energy are used to create the evaluation rules for transient radiation noise.