【作者】 谷磊；

【导师】 王树新；

【作者基本信息】 天津大学 ， 机械电子工程， 2011， 博士

【摘要】 海洋内部运动能量传递过程一般是由大尺度到小尺度、最终以微结构湍流的形式耗散。研究湍流能量耗散过程是建立完善海洋宏观运动物理模型、了解海洋内部混合的基础。此外,微结构湍流还对海水运动速度、温盐特性及水中溶解态、颗粒态物质的分布有显著影响,因此,海洋微结构湍流对于认识海洋内部变化规律具有重要意义。研究海洋微结构湍流的关键是得到湍流动能耗散率。剪切流传感器是目前微结构湍流测量的常用仪器,该传感器内部的压电陶瓷片受到海洋湍流的作用产生信号。剪切流传感器安装在其专用载体上,跟随载体以一定的速度在海水中运动,运动过程中剪切流传感器对海洋微结构湍流的水平或竖直方向的脉动进行测量,再根据海水粘度、载体运动速度等物理量可以得到所测量区域的海水微结构湍流耗散率。目前,对剪切流传感器结构设计、机械性能以及传感器载体的水动力学性能和相关实验仪器的研究并不多,而这些因素对湍流测量准确性产生影响。另外,我国海洋微结构测量仪器基本依靠引进国外技术,而目前需求量日益增大,因此开展海洋微结构测量仪器的研究非常必要。本文对剪切流传感器结构、传感器载体垂向剖面仪的水动力学性能等方面进行了较为系统的研究,开发出了新型剪切流传感器及其相关的实验仪器,得到了垂向剖面仪的运动特性,相关技术已经通过验收并得到实际应用。本文主要研究成果和创新点为:1.基于PVDF压电薄膜材料,设计了新型结构剪切流传感器。根据剪切流传感器结构特点和工作环境提出了采用流固耦合、压电耦合理论对传感器性能进行计算的方法,并将计算结果与已有实验数据进行比对,验证了该方法的可行性。2.研制出了传感器灵敏度标定系统,以及能够测试剪切流传感器动态性能的压力实验装置,并对其内部工作状态进行了仿真计算和实验研究。3.采用计算流体力学方法分析了垂向剖面仪水动力学特性,建立了其一般运动学方程,在此基础上研究了纵平面内剖面仪的运动规律。更多还原

【Abstract】 Turbulence is responsible for dissipating the kinetic energy in the Ocean at very small scales, and it is essential to set up ocean model that predict global circulation, climate change, and particle dispersal. Microscale turbulent mixing below the sea surface strongly influences the heat, mass and momentum exchange between the ocean and the atmosphere. Water velocity, heat, salinity, and nutrients are primarily dependent upon turbulence. So turbulence has significance to research the motion regularity of the ocean.In order to descirbe turbulence in the ocean, the magnitude of the turbulent velocity fluctuations and the rate of dissipation of turbulent kinetic energy should be measured or estimated. The most commonly used and best-suited sensor for measuring microstructure velocity fluctuations is the shear sensor. The sensing element is a piezo-ceramic bimorph beam which generates an electrical charge in response to cross-axial forces. The sensor is installed on the top of the profiler, and move with it. Profiler can be categorized as either vertical or horizontal profiler. Based on the signal and sensitivity of shear sensor, ocean viscosity and velocity of the profiler, dissipation of the turbulence can be computed.At present, there are little research on structure design, mechanical properties, and water dynamics of shear sensor and profiler. But such factors are critical to the measurement accuracy of the instruments. In addition,nearly all the ocean turbulence measurement instruments are imported in our country, with the further development on ocean science, more precise measurement instruments need be explored. Supported by national high technology of ocean monitor field, this paper presents a thorough study on the structure of shear probe and dynamics property of vertical profiler. New shear sensors and experiment instruments are explored, and technologies are passed the acceptance and put into practice.The main contributions of this thesis are summarized as follows:1. New shear sensor made of PVDF is developed. Based on the structure and work environment of shear sensor, fluid solid interaction coupling and piezoelectric coupling are introduced to compute the property of shear sensor. The result is coMPared with experiment, which suggests the method is feasible.2. The calibration machine system and dynamic test instrument are develped in order to acquire the sensitivity and test the property of the shear sensor.3. The hydrodynamic property of vertical profiler is studied by Computational Fluid Dynamics (CFD). The kinematics and dynamics equation are deduced, trajectory path and velocity of profiler are simulated.更多还原