声学测波仪在ZQA1—1型海洋站自动观测系统中的应用

在 ZQA1-1型海洋站自动观测系统中(简称系统),应用计算机软件配合声学测波仪进行波浪测量,提高了测波的可靠性。图1为系统中测波部分方框图。图中实线部分是声学测波仪电路框图,虚线部分为应系统测波要求而增加的。当开关 K 处于②的位置时,声学测波仪恢复原态,可以独立进行     

SBF1—1型近海遥测波浪仪简介

应用浮标测量海洋波浪是近十几年来国外广泛采用的测波手段之一。SBF1—1型近海遥测波浪仪即是一种定点的具有弹性系留系统的遥测波浪浮标。它主要适用于沿海台站、港口码头及海上石油平台等处测量波浪的波高和周期。浮标通过天线连续发射波浪信号,岸站接收系统可连续或定时接收记录。     

〈恩迪柯〉1156遥控测波仪

最近,我院首次从美国恩迪柯公司进口了一套1156遥控测波仪。货已到,待验收消化后即可正式投入使用。1156测波仪是原956测波仪的改进型,它以遥测浮标内的加速度计为传感器,是目前世界上最先进的测波系统之一。该系统使用甚为方便,不仅适用于测量近岸沿海波浪,也适用于远海测波,是当前交通、海洋、石油勘探和航海事业中一种较为理想的测波仪器。它的引进增加了我院现场测波研究工作的手段。 1156测波仪除了能如同956那样测取波浪的波高、波周期和波向外,如若配置一些部件,尚能进行风、气压、水温和气温等要素的测量。     

压力式波浪／潮位测量仪对比试验初报

介绍了新研制的压力式波浪／潮位测量仪和垂线测波记录仪、Ｓ４浪潮流仪在水深８．５ｍ处所作对比试验的结果。结果表明,潮 比测效果明显优于波浪的比测效果。应用压力式波潮仪测浪的比测结果尚可接受,但应该指出,当测量大浪时,误差会减小,其效果将合明显提高。为提高观测的质量,还应在水深较深处（５０ｍ）进行比测试验。     

“平均位置”法在波高观测中的应用

一、引言SBA1-2型岸用光学测波仪是海滨测站从事波浪观测的常规仪器(二型测波仪),它是在HAB-1(一型测波仪)改型基础上研制生产的。经过改型,克服了一型仪在分划板设计上采用等高逐步刻度法进行波高观测,随着波高的增加误差亦增大的缺点。由于在设计原理上采用了定点等高刻度刻划波高标尺,使二型仪的设计更为合理,测量精度也相应提高。但从设计原理所导出的“逐个波高计算”方法中可以看出,二型测波仪观测、计算繁索复杂,比一型的工作量增加了数倍以上,这也是当时二型仪难以推广的原因。能否找     

CBS型垂线测波仪

目前,世界上所用的各种测波仪器正朝着多功能和自动化方面发展。随着海浪理论研究的深入、水气交换及水位的精确测量等,都需要有一种精度高、频响宽、稳定性好和使用方便的测量仪器。CBS型测波仪满足了上述的要求。     

基于波面起伏相关性估计海浪波长的新方法

提出了一种实验室波长估计的新方法。在实验室中,使用同步测量的多个测波仪采集波面起伏数据,并根据不同测波仪数据的相关性,计算通过两个测波仪的波浪传播速度,并由此计算波浪波长,计算结果与传统的根据频散关系计算波长对比。分析结果表明:这种新的方法比原有的根据频散关系计算波长更为合理。同时,针对该方法分辨率较低的不足,本文提出了一种新的测波仪数据的插值方法。通过分析实验数据表明:这种新的插值方法有效地提高原有方法的波长计算精度。通过测波仪数据相关性及插值方法配合,该方法可以更合理计算海浪波长。     

测波浮标最佳投放位置的选择

本文论述了使用 HAB-2型岸用光学测波仪观测海浪要素时,其测点处浮标位置的选择是相当重要的。应从近岸波浪的最大反射距离、海流对波浪的影响及测波浮标与观测点间的水平距离等诸多因素综合考虑以选出最佳的抛放位置。     

Wave-Rider 67780系列测波仪数据采集和处理系统功能的改进

Wave-Rider 67780系列测波仪采用HP-85微机作实时数据采集和实时谱处理(200s/块)。所采集的原始数据块间不连续、数据块不贮存,难以满足波浪研究的需要。本文在以往工作的基础上,进一步采用1BM-PC系列微机代替HP-85微机并设计了专用软件包,从而可实现连续(时间任意)的实时数据采集、贮存以及实时波浪统计和Tukey海浪谱分析(1200s)。经多次波浪测量应用,证实该测波仪的实时数据采集贮存和实时数据处理能力得到明显提高。该软件包适用于其它类似测量系统,具有一定的应用价值。     

波浪能滑翔器走航式波浪要素测量试验分析

海洋中的海水波动作为海洋中一种重要的运动形式,关乎海洋工程建设、航海安全以及海洋能的利用等,因此波浪要素的测量成为海洋科学研究的重要对象之一。针对传统手段在波浪要素定点测量上存在的测点单一、操作复杂、成本较高等问题,提出一种使用无人自主移动平台波浪能滑翔器挂载测波传感器进行走航式波浪要素测量的方案,并与SBF7-1型测波浮标在同一海域进行比测试验。经过试验数据的对比分析,验证了波浪能滑翔器走航式波浪要素测量方案的可行性及存在的不足,为后期优化波浪能滑翔器走航式波浪要素测量方案,实现波浪要素的精准测量奠定了基础。     

乐清湾港池开挖后骤淤可能性分析

乐清湾避风条件好,潮流动力强,含沙量小,具有较好的建港条件。通过对骤淤机理的分析和试挖槽在台风期间的监测以及大风浪下的悬沙淤积的估算等多种研究后,认为乐清湾港池开挖后不会发生骤淤,实行浅水深用的开发方案是可行的。     

Disintegration of linear edge waves

It is demonstrated that offshore wavenumbers of edge waves change from imaginary wavenumbers in deep water to real wavenumbers in shallow water. This finding indicates that edge waves in the offshore direction exist as evanescent waves in deep water and as propagating waves in shallow water. Since evanescent waves can stably exist in a limited region while propagating waves cannot, energy should be released from nearshore regions. In the present study, the instability region is predicted based on both the full water wave solution and the shallow-water wave approximation.     

An ultrasonic device to measure surface displacements of water and floating bodies

Non-intrusive measuring instruments are desirable tools to investigate the response of vessels or marine structures subjected to water waves, whether in a laboratory or in the field. An ultrasonic sensing device is designed and built to measure surface displacements of a floating body. An ultrasonic sensor can sense any surface that lies in front of it, whether it is a solid or a liquid surface. In this study, a specialized electronic circuit board is designed to measure a wide range of surface displacements. The proposed system not only can be used to measure heave, surge, and pitch of a floating body continuously but also it can act as a water waveform recording instrument. The proposed ultrasonic measuring device is far more accurate than the current standard instruments (e.g. potentiometers) based on the simple fact that the measured surface is not disturbed. Furthermore, this device is of low manufacturing cost and has a practical size that renders it suitable for a broad range of applications. Hence, it can be used in a laboratory setup as well as in conducting field tests.     

Short-wave measurements by a fixed tower-based and a drifting buoysystem

The small-scale roughness of the sea surface acts as an important link in air-sea interaction processes. Radar and sonar waves are scattered by short surface waves providing the basis for remote sensing methods of the sea surface. At high wind speeds, breaking waves occur. Bubbles penetrate into the water and drastically increase acoustical reverberation, transmission loss and ambient noise. Thus, the development of short waves and wave breaking have to be known to apply radar remote sensing to the surface and to deduce from radar backscatter which sonar conditions prevail. To measure the wind dependence of short waves an experimental device was constructed for use from stationary platforms. It is nearly all-weather capable and can easily be handled by a crane. On the other hand, frequencies of short waves measured in a fixed position are extremely frequency shifted by currents. This limits the usefulness of tower-based measurements, e.g., the short wave modulation by wind and waves or currents can only be estimated in a rough approximation. Consequently, a buoy was developed to reduce the frequency shifts. The principle of the buoy is to drift in the local surface current and to follow the amplitudes of long waves. Therefore, short waves are measured in facets of long waves and the Doppler shifts are minimized. The wind is measured at a constant height above the long wave profile and relative to the moving facets. The paper describes the conventional measuring device and points out the necessity of the drifting buoy system. Examples of wind and wave spectra are presented and short wave modulations by long waves are depicted, too. From these measurements, new insights in short wave behaviour have to be expected     

深水波中进动共振的数值模拟研究

进动(precession)共振是一种非线性共振相互作用,2016年才有学者对这一现象进行研究。采用非静压二维自由表面流模型模拟了深水条件下重力波的进动共振现象。通过边界造波的方法产生双色波,分析了触发进动共振的初始条件;探讨了进动共振在小振幅前提条件下发生的简化初始条件。数值模拟分析两组对称测点,对不同测点的波面、能量谱进行对比分析。数值结果表明:非静压二维自由表面流模型可以模拟进动共振现象,并且可以采用双色波作为条件来研究深水五波进动共振现象,进动共振需要一定的能量转化时间,进动共振发生的条件是三波组合的进动频率等于一个系统存在的非线性频率。     

Detection of nonlinear waves and their contribution to ocean wave spectra Part I: Theoretical consideration

This is a Part I of a paper of nonlinearities of wind waves in the deep open ocean. First, considerations are given in order to verify the theoretical expression for bound waves from observed data. We compare the contribution of bound waves and double Bragg scattering to the second-order scattering, and we show that the contribution of bound waves is larger, and that bound waves can be detected by measuring the Doppler spectra of HF (high-frequency) radio wave scattering from the sea surface. Moreover, if the theory of the HF radio wave scattering from the sea surface is verified, so is the second-order perturbation theory for bound waves. Then, the contributions of bound waves to ocean wave spectra are investigated on the basis of the nonlinear theory. The bound waves are shown to modify frequency spectra and wave directional distributions at higher frequencies, and it is shown that although the modifications of frequency spectra are smaller for a two-dimensional field case than for a one-dimensional field case, they are not negligible at higher frequencies. On the other hand, the modifications of wave directional distributions are shown to be significant at higher frequencies. These discussions become significant only when bound wave predictions are verified in the open ocean. Consequently, it is shown that nonlinearities of water waves are important in considering both radio wave scattering from the sea surface and the detailed structures of ocean wave spectra at high frequencies.     

Static wave setup with emphasis on damping effects by vegetation and bottom friction

Wave setup can contribute significantly to elevated water levels during severe storms. In Florida we have found that wave setup can be 30% to 60% of the total 100-year storm surge. In areas with relatively narrow continental shelves, such as many locations along the Pacific Coast of the United States, wave setup can be an even larger proportionate contributor of anomalous water levels during major storms. Wave setup can be considered as comprising two components, with the first being the well-known static wave setup resulting from the transfer of breaking wave momentum to the water column. The second, oscillating component, is a result of nonlinear transfer of energy and momentum from the primary (linear) spectrum to waves with length and time scales on the order of the wave groups.Static wave setup is the focus of this paper with emphasis on effects due to internal or surface forces that act on the wave system and cause both dissipation of wave energy and transfer of momentum. In particular, the effects of wave damping by vegetation and bottom friction are considered. Linear wave theory is applied to illustrate these effects and, for shallow water waves, the setup is reduced by two-thirds the amount that would occur if the same amount of energy dissipation occurred in the absence of forces. Effects of nonlinear waves are then considered and it is found, for a shallow water wave of approximately one-half breaking height, that a wave setdown rather than setup occurs due to damping by vegetation and bottom friction.The problem of wave setup as waves propagate through vegetation was stimulated by studies to establish hazard zones associated with 100-year storm events along the shorelines of the United States. These storms can generate elevated water levels exceeding 4 to 6 m and can result in overland wave propagation. As these waves propagate through vegetation and damp, the question arose as to the contribution of this process to elevated mean water levels through additional wave setup.     

基于微结构图像的风生微尺度波频率谱初探

利用海面微结构光学测量装置实验获取到的微尺度波图像来给出风生微尺度波的波数谱,在此基础上利用频散关系建立微尺度波波数谱和频率谱之间的关系,最终得到微尺度波频率谱.对微尺度波的频率谱随频率变化的响应进行了研究,发现频率谱与频率的a次方成正比关系,a的值随风速的增加而增加,同一风速下a几乎为定值.     

晶体管等电阻接触式测波仪的研制

继电器接触式测波仪,由于使用了近百个继电器组及相应的电线和触头,显得相当笨重,在使用中还对其它同步测量的信号产生干扰;在此基础上发展的电阻接触式测波仪,在设计中需反复逐步实验才能达到直线性。而当盐度发生变化时还会产生不可忽视的非线性,因此使用上十分困难。根据上述问题,作者研制了新的等电阻接触式自动测波仪。