Keywords: 
• 分层流体 /
• 内波 /
• 等效源 /
• 拖曳细长体

Abstract: In this paper, we perform experiments on the time-space characteristics of internal waves generated by horizontally towed bodies with three aspect ratios in a stratified fluid with a halocline. By the real-time measurements of conductivity probe arrays which are arranged symmetrically in the transverse section of the stratified fluid tank, it is shown that the transition between the body-generated internal wave and the wake-generated internal wave is related to a critical Froude number F rc, which is linearly dependent on the aspect ratio. For F rF rc, the correlation velocities of internal waves are noticeably lower than the towing speeds, indicating that such internal waves in this range are dominated by the wake-forced effect, and that the Froude numbers with respect to the correlation velocities of such internal waves vary in a range from 0.43 to 1.18. The heights of such wake-generated internal waves nearly linearly increase with F r increasing regardless of the aspect ratio. Moreover, the patterns of body-generated waves are symmetric, while the patterns of wake-generated waves are not symmetric. Based on the experimental results and the equivalent source method which has been proposed to simulate the internal waves generated by a towed sphere, a new equivalent source method is developed to calculate the internal waves generated by towed slender bodies. For the body-generated waves, the method of designing the speed, length and diameter of the equivalent source is proposed. The symmetrical and anti-symmetrical equivalent source and their speed and size are also proposed for the wake-generated waves. The numerical results are in good accordance with the experimental results in the heights and patterns of waves, indicating that such a theoretical method and its parameter settings are reasonable and effective.