Thermal characteristics of vehicle wake induced by the interaction between hydrodynamic wake and cold skin

Abstract

The wake temperature signal generated by the motion of an underwater vehicle can be captured by infrared detectors, threatening the concealment of the vehicle. To clarify the formation mechanism and physical phenomena of thermal wake, detached-eddy simulations are conducted to establish a thermal wake calculation model, and the volume-of-fluid model is employed to capture the thermal wake characteristics of the water–air interface. Based on the interface heat diffusion and transfer, a high-resolution cold skin boundary layer is established to study the interaction between hydrodynamic wake and temperature boundary layer. The numerical results show that the surface thermal wake presents a long regular strip-shaped characteristic with eddy current structure, which is basically consistent with the results of outdoor wake infrared test in phenomenon and overall intensity. The wake thermal signature originates from the modulation of the cold skin microstructure at the water surface by the wake vorticity. By applying the proposed evaluation method for the thermal characteristics of water surface wakes, the influence of navigation parameters and cold skin parameters on the thermal characteristics of water surface wakes is systematically discussed, and the thermal characteristics of wakes and their influencing factors are summarized.