Stereoscopic measurement of a fluctuating free surface with discontinuities
Stereoscopic measurement of a fluctuating free surface with discontinuities
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DOI：
10.1088/0957-0233/16/10/003
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发表时间：
2005-10
影响因子：
2.4
通讯作者：
R. Tsubaki;I. Fujita
中科院分区：
文献类型：
--
作者：
R. Tsubaki;I. Fujita
本文提出了一种新的创新方法来测量二维水面形态。该方法使用由两个高分辨率CCD摄像机在立体位置排列捕获的一对连续图像。该方法的思想是使水的颜色为白色，这样当不规则图案的光投射到瞬时水面上时，瞬时水面看起来像具有清晰图案的固体表面。应该注意的是，该方法适合于精确地测量小振幅的波，同时稳健地测量不连续的表面。首先，我们解释的测量原理和实验过程中获得立体图像。其次，我们检查的测量精度，通过应用我们的技术，以静水表面和校准的波形板。最后，我们提出的应用程序的技术应用到实际的流场，如表面波和波纹产生的浅水箱。结果表明，我们可以跟踪小到1毫米的小波浪的传播。在另一个应用中，我们测量周期性的表面波动产生的安装在一个开放的通道流的非对称腔，表现出鲁棒性的技术适用，即使当一个不连续的表面与波破碎发生在测量过程中。
This paper presents a new innovative method for measuring two-dimensional water surface configurations. This method uses a pair of sequential images captured by two high-resolution CCD cameras arranged in a stereo position. The idea of the method is to make the water colour white so that the instantaneous water surface appears like a solid surface with a clear pattern when an irregular pattern of light is projected onto it. It should be noted that this method is suitable to measure waves with small amplitude accurately and at the same time a discontinuous surface robustly. First, we explain the measurement principle and the experimental procedure for obtaining stereo images. Secondly, we examine the measurement accuracy by applying our technique to a still water surface and calibrated wavy plates. Finally, we present applications of the technique applied to actual flow fields such as surface waves and ripples generated in a shallow water box. The result shows that we can trace the propagation of small waves as small as 1 mm. In another application, we measure periodic surface fluctuation generated at an asymmetric cavity installed in an open-channel flow, demonstrating robustness of the technique applicable even when a discontinuous surface with wave breaking occurs in the course of the measurement.