【作者】 李俊；

【导师】 陈刚；

【作者基本信息】 上海交通大学 ， 船舶与海洋结构物设计制造， 2016， 博士

【摘要】 海洋深水试验池是进行海洋深水结构物试验研究不可或缺的基础研究设施,同时它也是发展海洋高新技术重要的技术支撑平台。在海洋深水试验池实现对风、浪、流良好的物理模拟是研究各类海洋结构物在其作用下水动力性能的基本要求和必要手段。其中,波浪是影响海洋工程最重要的环境因素,因此对波浪的模拟是进行海洋工程结构物模型试验的首要条件,波浪模拟的准确与否将直接影响试验结果的正确性和可靠性。目前,由若干独立摇板组成的多单元造波机成为海洋工程水池对波浪进行模拟的重要设备,可在水池对斜向长峰波浪和更加真实反映实际海浪的三维短峰波进行物理模拟,为开展各类深水海洋结构物模型试验、水动力研究以及波浪理论研究等提供了便利的条件。海洋深水池是进行海洋工程模型试验的基础设施,全面掌握、了解深水池的波浪模拟性能是重要的、基本的课题。本文以上海交通大学海洋深水池及其所配备的双边多单元造波机为基础,对方形海洋深水池波浪模拟性能进行了系统地分析与研究。主要工作内容包括:1)海洋深水池及双边多单元造波机波浪模拟性能分析通过不规则波浪周期与波高联合分布函数,利用无因次条件波高周期概率密度函数,研究了决定造波机对不规则波浪模拟能力的特征波高及其周期的选择方法,确定了造波机对不规则波浪进行模拟时的最大造波能力;针对配备有双边多单元造波机及组合式弧形消波滩的海洋深水池硬件特性,对影响方形水池波浪模拟质量的共性问题进行了分析。明确了海洋深水池波浪模拟的误差源。误差源主要包括:绕射、折射、反射、局部扰动和控制系统误差等;对由波浪模拟方法产生的影响双边多单元造波机波浪模拟质量的关键问题进行了研究,获得了各传播方向角度所能模拟的理想规则波浪的最小周期和避免杂波产生的规则波浪频率与波向角范围等;2)海洋深水池波浪模拟性能试验研究利用浪高仪阵列对在海洋深水池内,由双边多单元造波机所生成的长峰波浪模拟性能,包括规则波浪传播方向精度、波高及周期空间分布均匀性、不规则波浪重复性、平稳性等进行了全面的试验研究与分析。试验结果显示,由双边多单元造波机在深水池内所模拟的长峰波浪能够在较大区域内为海洋工程模型试验提供良好的波浪环境条件;确定了方形水池内,由双边多单元造波机所模拟的三维短峰波浪有效实验区范围并通过试验进行了验证。利用浪高仪阵列对所生成的三维短峰波浪波场分布状况进行了测量与分析,结果表明,当主波向与造波面呈一定夹角时,在方形海洋深水池,利用双边多单元造波机能够对三维短峰波浪进行良好的物理模拟,同时在水池中较大区域内,所生成波浪波场分布具有良好的空间均匀性。在短峰波浪模拟方面,双边多单元造波机较单边造波机具有明显优势;3)验证组合式弧形消波滩消除反射波能力利用FLUENT软件开发了包括弧形组合式消波滩在内的二维数值波浪水池,实现了规则波浪的数值模拟。采用两点法对模拟的不同周期、波高的规则波浪进行时域分离并求取反射系数,并与相应的模型试验进行了对比,对海洋深水池消波设施消除反射波的能力进行了验证。结果显示,在海洋工程模型试验常用周期和波高范围内,海洋深水池组合式弧形消波滩具有优良的反射波消除能力。论文研究成果对于海洋深水池高质量地模拟波浪,并为海洋工程结构物模型试验提供良好的波浪环境条件具有重要的工程实际意义;为探索提高方形水池内波浪模拟质量的方法奠定了基础;对深水池实现复杂波浪物理模拟也具有重要的参考价值。更多还原

【Abstract】 Deepwater Offshore Basin is an indispensible infrastructure facilities in the study of ocean engineering structure model test,and it is an important technical supporting platform to develop top technology industries in ocean engineering.High quality simulation of winds,waves and currents in ocean engineering basin is a basic requirement for model tests of various ocean engineering structures under ocean environment conditions.Wave simulation is the prerequisite to ocean engineering experiments.Correct wave simulation is crucial to the accuracy and reliability of model test results.Nowadays,segmented wavemakers,consisting of numerous individually programmed paddles,have become important wave simulation equipment in ocean engineering basin.Oblique long-crested waves and 3D short-crested waves which well reflect the true situation of real sea can be generated by the regular motion of each paddle.Segmented wavemakers play an increasingly important role in laboratory study of waves and their interaction with ocean engineering structures.Therefore,thorough understanding and complete control of wave simulation performance generated in deepwater offshore basin becomes basic and important research topic.Based on the Deepwater Offshore Basin equipped with two sided-segmented wave makers in Shanghai JiaoTong University,the simulation performance of waves created in the basin are analyzed in the paper.The main findings of the doctoral dissertation can be summarized as the followings:1)Study on the simulation performance of waves generated by two-sided segmented wavemakers in rectangle deep ocean basin.Based on the joint distribution function of periods and amplitudes of random waves,using dimensionless conditional probability density function of wave period to assume wave height,a method is proposed for the selecting of characteristic wave height and period,which play decisive role for maximum capacity of wavemakers to simulate irregular waves.The maximal capacity for irregular waves generated from the system is determined.Based on the hardware features of deep ocean basin equipped with two-sided segmented wavemakers and two-sided wave sbsorptions,general issues affecting the wave simulation quality are analyzed in the paper.The analytical results make clear the major error sources affecting the wave simulation quality in basin.The major error sources mainly include diffraction,refraction,reflection,local disburbances and the error of control system etcThe simulation method of two-sided segmented wavemakers are discussed and some key problems affecting the simulating quality are researched.The minimal period of ideal regular waves,simulated at arbitrary angle,the range of frequency,and direction of regular wave to avoid spurious waves are determined2)Laboratory Research on the simulation performance of waves generated by two-sided segmented wavemakers in deep ocean basinA wave probes array is arranged in model test area in deep ocean wave basin to collect time series of long-crested waves generated by two-sided segmented wavemakers.Thorough understanding of wave field distribution of long-crested waves created in deep ocean basin is gained by analyzing accuracy of propagation direction,the spatial homogeneity of wave heights and periods,the stability and repeatability of simulated irregular waves etc.Experimental results show that the long-crested waves generated by two-sided segmented wavemakers have good uniformity within a big model test area in deep ocean engineering basin,which offers excellent wave environments for seakeeping model tests of various ocean engineering structuresThe range of effective test area of 3D short-crested wave is determined and proved by experiments.The experimental investigation into the wave field distribution of short-crested waves generated by two-sided segmented wavemakers is conducted by using an array of wave gauges.The analytical results of generated waves reveal that the two-sided segmented wavemakers can simulate short-crested waves well and the wave field of simulated waves has good uniformity within the model test area when the main direction is at a certain angle with the normal line of wave generators.Two-sided segmented wave generator has obvious advantages over single-sided segmented wave generator when simulating short-crested waves.3)Validation of capacity of eliminating the reflected waves of combined curved type absorbing beach.A 2D numerical wave basin including combined type absorbing beach is developed by using the FLUENT software.Numerical simulation of regular waves is thus realized.Using two-point method,the reflection coeff-icient are calculated by the incident and reflected waves separated from simulated composite waves with different periods and wave heights in time domain.The results are compared against model tests,and the performance of cambered combined type beach equipped in basin is analyzed and verified.The analysis indicates that in the range of normal wave heights and periods for model tests,the combined curved type absorbing beach has excellent capacity to eliminate the effects of reflected waves.Through this thesis research,a comprehensive understanding about the simulation performance of waves created by two-sided segmented wave generator in rectangle deep ocean basin is achieved.The study findings reported in this paper are of important engineering practical significance for high quality wave simulation and providing excellent wave environment conditions for model tests of various ocean engineering structures in deep ocean basin.Meanwhile,the research is of key referential value to improve wave simulation quality within reasonable and practicable extent,and realize of complex waves simulation in deep ocean engineering basin.更多还原