基于高速摄像技术的流体作用力试验

doi:10.11988/ckyyb.20230301

长江科学院院报 ›› 2024, Vol. 41 ›› Issue (8): 90-95.DOI: 10.11988/ckyyb.20230301

基于高速摄像技术的流体作用力试验

周双¹(), 张根广², 许晓阳²

¹ 青海民族大学土木与交通工程学院,西宁 810000
² 西北农林科技大学水利与建筑工程学院,陕西杨凌 712100

收稿日期:2023-03-27 修回日期:2023-05-22 出版日期:2024-08-28 发布日期:2024-08-13
作者简介:
周双(1989-),男,内蒙古开鲁县人,助教,博士,研究方向为水力学及河流动力学。E-mail: 839298039@qq.com
基金资助:
国家自然科学基金面上项目(51879227); 国家自然科学基金面上项目(51279170); 青海民族大学校级自然科学项目(23GCC20)

Experimental Investigation of Fluid Forces Using High-speed Imaging Technology

ZHOU Shuang¹(), ZHANG Gen-guang², XU Xiao-yang²

¹ School of Civil and Transportation Engineering,Qinghai Minzu University,Xining 810000,China
² College of Water Resources and Architectural Engineering, Northwest A & F University, Yangling 712100,China

Received:2023-03-27 Revised:2023-05-22 Published:2024-08-28 Online:2024-08-13

摘要/Abstract

摘要：

针对颗粒在动水中的流体作用力问题,采用高速摄像技术对颗粒的运动过程进行观测,通过求解圆球及天然泥沙跃移运动过程中的力学方程,得到拖曳力系数及上举力系数。试验结果表明:①动水中颗粒非匀速运动时的拖曳力系数、静水中颗粒非匀速运动时的拖曳力系数与匀速运动时的拖曳力系数均随着雷诺数的增加而减小,颗粒与水流之间的相对运动速度越接近于颗粒沉速,三者间的差异越小;当颗粒与水流之间的相对运动速度等于颗粒沉速时,三者近似相等。②形状对上举力系数的影响较对拖曳力系数的影响更明显,天然泥沙的拖曳力系数大于圆球的拖曳力系数,天然泥沙的上举力系数小于圆球的上举力系数。最后,构建了圆球及天然泥沙的拖曳力系数及上举力系数公式,公式计算值与实测值符合较好。

关键词: 流体作用力, 高速摄像技术, 圆球, 天然泥沙, 跃移, 拖曳力系数, 上举力系数

Abstract:

Particle motion was observed using high-speed imaging technology to investigate the fluid forces acting on particles in flowing water. The drag coefficient and lift coefficient were obtained by solving the mechanical equations for saltating spheres and natural sediments. Experimental results manifest that: 1) The average drag coefficient for particles with nonuniform velocity in flowing water, particles with nonuniform velocity in stilling water, and particles with uniform velocity in stilling water all decrease with the increase of Reynolds number. The difference between these coefficients diminishes when the particle-fluid relative velocity approaches the settling velocity. When the relative velocity equals the settling velocity, the coefficients are approximately equal. 2) Shape has a greater influence on lift coefficient than on drag coefficient; natural sediments exhibit larger average drag coefficient compared to spheres, whereas spheres demonstrate higher average lift coefficient than natural sediments. The equations for drag coefficient and lift coefficient of spheres and natural sediments are established, and the calculated values agree well with measured data.

Key words: fluid forces, high-speed imaging technology, sphere, natural sediment, saltation, drag coefficient, lift coefficient

中图分类号:

TV142.2

周双, 张根广, 许晓阳. 基于高速摄像技术的流体作用力试验[J]. 长江科学院院报, 2024, 41(8): 90-95.

ZHOU Shuang, ZHANG Gen-guang, XU Xiao-yang. Experimental Investigation of Fluid Forces Using High-speed Imaging Technology[J]. Journal of Yangtze River Scientific Research Institute, 2024, 41(8): 90-95.

图/表 6

图1 试验装置

Fig.1 Experimental devices

表1 试验条件

Table 1 Experimental conditions

序号	Q/ (L·s^-1)	H/cm	R/cm	J	U/ (m·s^-1)	Re_U
1	44.444	11.100	8.427	0.001 0	0.572	48 204
2	50.000	12.100	8.992	0.001 0	0.590	53 078
3	61.111	13.500	9.742	0.001 0	0.647	63 001
4	50.000	12.800	9.372	0.000 4	0.558	52 301

图2 跃移颗粒受力示意图

Fig.2 Forces acting on saltating particle

表2 不同形状的天然泥沙各参数的取值范围

Table 2 Range of experimental values for each parameter of natural sediments with different shapes

形状	Re	C_D	C_L	n
圆球	218~864	0.100~10.134	0.252~9.690	65
近似圆球	719~1 179	0.365~0.716	0.332~1.170	35
片状	496~1 139	0.371~2.786	0.016~1.219	50
椭球	461~863	0.523~3.209	0.111~1.798	142

图3 不同雷诺数时的拖曳力系数

Fig.3 Drag coefficient at varied Reynolds number

图4 不同雷诺数时的上举力系数

Fig.4 Lift coefficient at varied Reynolds number

基于高速摄像技术的流体作用力试验

Experimental Investigation of Fluid Forces Using High-speed Imaging Technology

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