Numerical study of submerged body tail linearization in a strongly stratified fluid on the characteristics of generated internal waves

Underwater motion generates internal waves in a density-stratified seawater environment. These waves can persist for several days in oceanic regions, making them detectable by synthetic aperture radar (SAR). To clarify the effect of tail linearization on the internal wave characteristics of an object, this paper builds a strongly stratified fluid flume based on the delayed detached eddy model (DDES), through which we numerically simulate the internal waves characteristics of two models, namely, a tail-planar type and a cylindrical rear spherical type. The numerical results show that the turbulent wake of the cylindrical rear spherical type diverges to both sides under the low and high Froude (Fr) number, leading to an increase in the amplitude of the generated volume effect internal wave and wake angle, but the wavelength of the volume effect internal wave is almost the same for both. Notably, at high Fr numbers, the influence of the trailing effect internal wave of the object with a linearized tail is significantly reduced. The tail-planar type of internal waves shows violent fluctuations over long distances and high-intensity violent changes in locally concentrated regions. In contrast, the internal waves of the object with tail linearization show slight fluctuations over long distances. •The effect of the linearization of the cylindrical tail on the features of the generated internal waves is investigated, and the impact on the volume effect and trail effect internal waves are explored separately.•The trailing internal wave properties of the two objects at different Fr numbers are analyzed, including the wave heights, wavelengths, and the transitions and connections between the two sources of the internal waves.•The effect of linearization of the tail of an object on the trailing effect internal wave is explored by analyzing the wavefront and waveform diagrams of the internal waves.•The effect of the linearization of the tail of an object on the volume effect internal wave is investigated by analyzing the wave surface divergence diagram of the internal waves and the waveform diagram of the volume effect internal wave.