Optimized designing of suspension system of sonar against irregular wave/shear current using FEA

Abstract

Under the complex current shears, the sonar system do not make their performance in the optimum manner in all oceanographic circumstances since these were first intended for typical blue water ocean environments. Under these circumstances, the buoy cause the sensor arrays to deflect/tilt at some angles usually more than 10 degrees in Yaw rotation and kite-up to beyond their specification in the shallower depths. Therefore, a coupled numerical analysis becomes necessary for the structural responses and motion behavior of a sonar suspension system subjected to irregular waves represented by JONSWAP (Joint North Sea Wave Project) spectrum and to optimize the sonar suspension system against complex wave and current fields. A comprehensive sensitivity analysis under three sea depths is carried out by changing the length of mooring lines, mass of hydrophones, area of drogue, height of wave and area/coefficient of drogue attached. The floating surface is represented by hydrodynamic pressure panels while cables are discretized using a series of Morison elements. Linear wave theory with Wheeler stretching method and stoke 2nd order wave theory are used for the computation of wave kinematics. These results then validated with theoretical formulations which ensure the integrity of tool and simulation. Such methods have been extremely beneficial in building the designer confidence and burgeoning the flairs to accommodate the relevant industry according to one's expectations.