基于PIV技术的阶梯溢洪道流场和涡量测试

鉴于阶梯溢洪道流场和涡量场分析对其消能特性的研究非常重要,利用粒子图像测速技术(PIV)测试了阶梯溢洪道滑行水流的二维流速场和涡量场,并分析说明了模型装置、仪器测试区域和相应参数设置。通过处理粒子图像获得模型水面线,验证了模型的水流流态为滑行流;从~#3～~#5阶梯的流速等值线分布特征得到阶梯滑行主流沿水深方向的流速变化,台阶凹角内旋滚水流的流速和转动周期;从~#3～~#5阶梯的垂直涡量场等值线分布,得出阶梯溢洪道滑行流态旋转水流产生的原因和运动方式,验证了阶梯溢洪道水流紊动耗散的主要原因;并通过计算阶梯消能率,说明了试验模型的消能效果。对PIV技术用于其他消能工消能特性的研究提供了参考。

Flow Field and Vorticity Measurement of Stepped Spillway Based on PIV

The flow field and vorticity field analysis of stepped spillway are very important for the study of its dissipation characteristics. In this paper, particle image velocimetry (PIV) is used to test the two-dimensional velocity field and vorticity field of the skimming flow in stepped spillway. The flow profile of the model is obtained by processing the particle image, and it verifies that the flow pattern of the model is skimming flow. The velocity contour distribution of step 3, 4, 5 were obtained: velocity distribution follows the water depth of stepped spillway skimming flow mainstream, and revolves flow velocity and rotationl period of water flow in the concave angle of step; The vorticity contour distribution of step 3, 4, 5 were obtained: reason and movement mode of skimming flow in stepped spillway, which verifies the main reason of the flow turbulence dissipation in stepped spillway; The energy dissipation effect of the model was illustrated by calculating the stepped energy dissipation rate. This paper provides reference for the study of PIV technology applied to other energy dissipators.