摘要:
针对文献[1]中非旋性自由表面周期性规则前进重力波传递在均匀流中的理论解析,本文以与前进波波向同向与反向的均匀流两种特例情况进行试验测量,所得的波形曲线、流速分布、流体质点的运动轨迹与运动周期及其质量传输速率与Lagrange平均高程等特性,均与文献[1]中全以Lagrange方式所得的三阶解结果符合得很好.这证实本研究取定的标注流体质点的参数,正好为其在原静止水中的位置坐标值.同时亦证实波流场中由流体质点所构成的波形曲线,其波长皆同于（纯）前进波者,而其传播速度为（纯）前进波波速与均匀流流速之和是具Doppler效应的;而流体质点的运动周期与其运动周期平均高程,及其质量传输速率扣掉均匀流流速等,都与（纯）前进波的相符.另外,亦揭示出流体质点的运动轨迹,在前进波波向与均匀流同向中,当流体质点在波谷断面处时沿前进波波向的流速分量为反向、零与正向时,则其形状分别为朝波向前进的扁长辐状余摆线,在波谷断面处成尖点朝下的滚轮状线与短辐形余摆线;而在前进波波向与均匀流反向中,当流体质点的质量传输速率为沿前进波波向为正向与零时,则其形状分别为朝波向前进的缩短的扁长辐形余摆线与长轴在前进波波向上的椭圆形封闭曲线;而当流体质点的质量传输速率为反前进波波向,但质点在波峰断面处时沿前进波波向的流速分量分别为正向、零与反向时,则其形状分别为反波向前进的倒扁长辐形余摆线,在波峰断面处成尖点朝上的倒滚轮状线与倒短辐形余摆线.
Abstract:
The quantitative experiments are made to measure the motional characteristics of water particles in the progressive gravity waves propagating on following and reversing uniform currents.The theoretical results of the third-order Lagrangian solution in Part 1 are shown good agreements with those measured by the experiments for the wave-form,the velocity distribution,the mass transport velocity,the particle trajectory,particle＇s motion period and Lagrangian mean level.It is also verified that identifying parameters of each particle is equal to the coordinates of its position in a still water.Consequentially,the wavelengths of the wave-forms constituted by the particles in the field are all equal to that of the progressive waves and their propagating speeds are the sum of the velocities of the progressive waves and the uniform current as the so-called Doppler effect is proved,but the motion periods and the Lagrangian mean levels of particles are the same as those in the progressive waves.The variations of the orbital forms of particles in the field are also revealed that the orbits like the prolate trochiod,the cycloid and the curtate trochoid are presented in the case of following uniform current as the horizontal velocity components of particles at the section of wave trough are,respectively,negative,zero and positive in the propagating direction of the progressive waves,and that the orbits like the prolate trochoid and the ellipse are occurred in the case of reversing uniform current as the mass transport velocities of particles are,respectively,positive and zero in the propagating direction of the progressive waves,and that the orbits like the turned prolate trochoid,the turned cycloid and the turned curtate trochiod are appeared in the case of reversing uniform current when the mass transport velocities of particles are negative and the horizontal velocity components of particles at the section of wave crest are,respectively,positive,zero and negative in the propagating direction of the progressive waves.
首页
登录
注册
下载: