An experimental investigation of breaking waves produced by a towed hydrofoil

Author:

Abstract

This paper presents the results of experiments on breaking waves produced by towing a submerged, two-dimensional hydrofoil at constant depth and speed. The wave field consists of a breaker followed by a train of lower, non-breaking waves. The breaker has a small zone of turbulent water riding its forward slope; this zone is called the breaking region. Measurements were made of surface height profiles, the vertical distribution of mean horizontal velocity in the wake of the wave, and the vertical thickness of the wake. The results support the hypothesis that the breaking region imparts a shearing force along the forward slope equal to the component of its weight in that direction. The force produces a turbulent, momentum-deficient wake similar to the wake of a towed, two-dimensional body in an infinite fluid. The vertical thickness of the wake grows in proportion to the square root of distance behind the breaker. The momentum deficit is approximately equal to the maximum momentum flux of a Stokes wave with the same phase speed as the breaker. The surface profile measurements yield several results: the proper independent variables describing the wave are its speed and the slope of its forward face. The relation between breaking wavelength and speed follows the finite-amplitude Stokes wave equation. The amplitude and the vertical extent of the breaking region are both proportional to the phase speed squared; however, they are not functions of the slope of the forward face of the wave. The breaking region has a small oscillation in its length with a regular period of 4.4 the period of a wave with phase speed equal to the hydrofoil speed. The amplitude of the oscillation diminishes with time. It is believed that this oscillation is due to wave components produced when the foil is started from rest.

Publisher

The Royal Society

Subject

Pharmacology (medical)

Reference16 articles.

1. B attjes J . A. & Sakai T. 1980 A b stra c t from In t. Conf. Coastal Sydney A ustralia M arch 1980 pp. 370-371. In s titu tio n of E ngineers A u stralia.

2. D onelan M. A. 1977 W hitecaps a n d m o m en tu m tran sfer. Turbulent fluxes through the sea surface wave dynamics and prediction (ed. A. F a v re & K . H asselm ann) pp. 273-287. New Y ork: Plenum Press.

3. D uncan J . H . 1978 The dynam ics of break in g surface waves. D octoral d issertatio n T he Jo h n s H opkins U niversity B altim ore M aryland.

4. K jeldsen S. P. & Olsen G. B. 1971 B reaking w aves (16 m m film). T echnical U n IV ersity of D enm ark L yngby.

5. L am b H . 1945 Hydrodynamics.New Y o rk : D over Publications.

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3