Investigation on the thermohaline structure of the stratified wake generated by a propagating submarine

The in situ thermohaline distribution of the wake contains a critical source of information for submersible detection. In this work, a stratified thermohaline wake model, in which major fluid properties vary with temperature and salinity, is presented to address heat and mass transfer characteristics in the stratified wake signatures induced by a propagating submarine via Large-Eddy Simulation (LES) approach. Of particular interests are the range and intensity of the wake signatures. The instantaneous fields reveal the evolutions of the temperature and salinity fields, showing the regional features of wake signatures. As the key diagnostic variables, the perturbation variations in temperature and salinity are quantified at the wake region defined by wake amplitude. Subsequently, the range and intensity of the wake signatures generated by submarines with different velocities are analyzed to illustrate the effects of velocity. The magnitudes of the perturbations in stratified flows are at significantly detectable levels, indicating that the submersible detection based on the temperature and salinity variations is a feasible and promising approach. The scientific findings provide useful insight for the deep understanding of the evolution of stratified flow, and support further research on optical and lidar tracking of the submersible vessels.