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目的:在振荡水柱装置研究中,通常通过不同的孔口几何特征来改变能量俘获系统的特性,但其具体流动特性却鲜有报道。本文探讨孔口几何特征(形状、尺寸和开孔率等)对流动特性的影响机制,理解影响能量俘获系统特性的关键因素,研究其对振荡水柱装置水动力特性和波能提取的影响规律,并评估波能提取性能指标的有效性。创新点:1.提出了两点测量法来重构振荡水柱腔室内液面;2.建立了孔口流动特性与孔口几何特征的关系式;3.提出了仅测量腔室内气压即可获得波能提取功率的方法;4.该方法可扩展至非二维矩形腔室及斜向波。方法:1.采用不同尺寸狭缝孔和圆形孔来模拟非线性能量俘获系统;2.通过一系列波浪水槽试验,对振荡水柱装置的水动力特性及波能的提取展开研究;3.采用二次损耗系数和收缩系数来描述孔口往复流动特性,并构建其与孔口几何特征的关系;4.通过两点测量法获取振荡水柱腔室内的准确信息;5.评估压力波动系数和液面放大系数作为振荡水柱装置波能提取性能指标的有效性。结论:1.两点测量法能够重建二维矩形振荡水柱腔室内液面的瞬时空间分布,消除了单点法的测量偏差;2.孔口相对厚度及振荡气流对可被视为薄壁的圆形孔的影响可以忽略不计,但对不能视为薄壁的狭缝孔的影响显著;3.本文提出的二次损耗系数经验公式可用于(1)通过孔口几何尺寸设计其流动特性和(2)通过仅测量腔室内气压来计算波能提取功率;4.用作振荡水柱装置的波能提取性能指标时,压力波动系数比液面放大系数更为可靠。
OBJECTIVE: In the study of oscillating water column apparatus, the characteristics of energy trapping system are usually changed by different geometric characteristics of orifice, but the specific flow characteristics are seldom reported. In this paper, the mechanism of the influence of geometric characteristics (shape, size and open area) of the orifice on the flow characteristics is discussed, the key factors affecting the characteristics of the energy capture system are understood, and the influence of the geometry, And evaluate the effectiveness of wave energy extraction performance index. Innovative points: 1. Proposed a two-point measurement method to reconstruct the liquid level in the oscillating water column chamber; 2. The relationship between the orifice flow characteristics and the geometric characteristics of the orifice was established; 3. It was proposed that only measuring the pressure in the chamber 4. The method can be extended to non-two-dimensional rectangular cavity and oblique wave. Methods: 1. Using different sizes of slit holes and circular holes to simulate the nonlinear energy capture system; 2. Through a series of wave tank test, the hydrodynamic characteristics of oscillating water column device and extraction of wave energy research; 3. using Secondary loss coefficient and contraction coefficient to describe the reciprocating flow characteristics of the orifice and build its relationship with the geometric features of the orifice; 4. Accurate information in the oscillation water column chamber is obtained by two-point measurement method; 5. Evaluation of the pressure fluctuation coefficient and the liquid Surface Magnification Coefficient as an Oscillating Water Column Wave Extraction Energy Efficiency Index. The two-point measurement method can reconstruct the instantaneous spatial distribution of the liquid surface in a two-dimensional rectangular oscillating water column chamber and eliminate the measurement deviation of the single-point method; 2. The relative thickness of the orifice and the oscillating airflow can be regarded as thin-walled The influence of the circular hole is negligible, but the influence of the slit hole which can not be regarded as the thin wall is significant.3. The empirical formula of the secondary loss coefficient proposed in this paper can be used to (1) design the flow characteristics through the orifice geometry and (2) Calculating the wave energy extracted by measuring the pressure in the chamber only; (4) When using the wave energy extraction performance index of the oscillating water column device, the pressure fluctuation coefficient is more reliable than the liquid level amplification factor.