Session: 06-16-01 Wave Mechanics, Modeling and Wave Effects - I

Submission Number: 173279

Surface Manifestations of Internal Wave Wakes Generated by a Moving Slender Body 

A slender body moving through a stratified fluid generates internal waves through displacement, vortex shedding, and wake turbulence, which propagate upward and modulate the free surface. These disturbances alter sea surface roughness and appear as bright or dark streaks in Synthetic Aperture Radar (SAR) imagery, underscoring the importance of understanding the coupling between internal wave wakes and surface wave responses for hydrodynamic modeling and underwater target detection. In this study, Particle Image Velocimetry (PIV) is employed in a large-scale stratified tank to investigate the internal wave wake generated by a moving slender body and the associated surface wave response. The results reveal that under low internal Froude number conditions, the surface response is dominated by first-mode internal waves exhibiting concentrated energy and high spatial coherence. As the internal Froude number increases, the amplitude of the first-mode component decreases, while high-frequency, short-wavelength surface waves become predominant, although low-frequency signatures remain evident. Meanwhile, the surface pattern undergoes a clear transition from a divergent “V”-shaped structure at low speeds to a classical Kelvin wave system at higher speeds, primarily driven by the emergence and predominance of transverse waves. As the frequencies of internal waves are inherently constrained by the upper bound of the buoyancy frequency, they remain substantially lower than those of surface waves, which are characterized by higher frequencies, shorter wavelengths, and radiation angles that vary systematically with the internal Froude number. The distinct spectral and spatial attributes of these two wave systems delineate the underlying dynamical linkage between internal wave wakes and their surface manifestations, thereby providing a rigorous physical basis and methodological framework for hydrodynamic wake detection in stratified marine environments.

Presenting Author: Ren Liqun Shanghai Jiao Tong University

Presenting Author Biography: Ren Liqun is a Ph.D. candidate at Shanghai Jiao Tong University. Research focuses on the generation of internal waves induced by underwater vehicle motion in stratified fluids. Main research interests include the generation mechanisms and propagation characteristics of internal waves and their effects on surface performance. Recent work combines theoretical analysis and numerical simulation to reveal the formation mechanisms of internal waves generated by moving bodies in stratified fluids, providing theoretical support for ocean engineering and the design of underwater vehicles.

Authors:

Ren Liqun Shanghai Jiao Tong University
Changhong Zhi State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University
Yunxiang You Shanghai Jiao Tong University
Zhongdi Duan Shanghai Jiao Tong University