摘要
通过模拟雨滴溅蚀试验,探究液滴定点脉冲式打击对非均匀沙的溅蚀影响。试验对4种中值粒径的非均匀沙(1,2,3,3.7 mm)在4种坡度(0°,15°,25°,35°)条件下,采用直径3.65 mm的脉冲式液滴进行试验,对比其溅蚀过程和溅蚀坑型得出结论:相同直径的液滴在同坡度同中值粒径的非均匀沙坡面进行试验,脉冲式液滴对其影响比单液滴更明显,液滴连续打击具有一定的“叠加效应”,下垫面坡度及中值粒径的变化对溅蚀过程及溅蚀坑型也有明显影响。液滴初始打击赋予颗粒不稳定性,随着液滴持续打击,中心颗粒被压实形成塌陷,周围颗粒在侧压力和液滴打击的冲量作用下向四周呈抛物线跃移,形成粗颗粒松散沉积物,进而粗化发展形成溅蚀坑。随着坡度增加坡面稳定性变差,溅蚀坑坑口直径变大、上壁变陡、下壁变缓,下坑唇处颗粒堆积量增加,更易失稳垮塌。同时中值粒径越大细砂受到的遮蔽作用越强,液滴的能量损失越大,用于破坏下垫面原始结构的能量越少,形成溅蚀坑越难。
This paper investigates the effect of the fixed-point pulse strike of droplets on the sputtering erosion of non-uniform sand by simulating raindrop sputtering tests.The experiments are conducted on four kinds of non-uniform sand with median particle size(1,2,3,3.7 mm)at four different slopes(0°,15°,25°,35°)with 3.65 mm diameter pulsed droplets.By comparing the sputtering erosion process and the sputtering pit type,this paper has drawn the following conclusions:The effect of the pulsed droplets on the non-uniform sand slope surface is more obvious than that of the single droplet,and the droplets produce a certain“superposition effect”when striking continuously.The change of the slope of the underlying surface and the median particle size also has a significant impact on the sputtering erosion process and the sputtering pit type.The initial strike of droplets makes the particles unstable.With the continuous strike of droplets,the central particles are compacted to form a collapse,and the surrounding particles leap around under the action of side pressure and the impulse of droplet strike,and coarse particles are formed around the collapse to form loose deposits,and the coarsening of the underlying surface develops into a sputtering pit.As the slope increases,the stability of the slope surface deteriorates,the diameter of the pit opening of the sputtering pit becomes larger,the upper wall becomes steeper,the lower wall becomes slower,and the accumulation of particles at the lower pit lip increases,making it easier to destabilize and collapse.At the same time,the larger the median particle size,the stronger the shading effect on the fine sand,the greater the energy loss of droplets,the less energy used to destroy the original structure of the underlying surface,the more difficult it is to form sputtering pits.
作者
徐嘉宁
彭清娥
张瑞雪
鹿泽洋
XU Jia-ning;PENG Qing-e;ZHANG Rui-xue;LU Ze-yang(Key Laboratory of Hydraulics and Mountain River Engineering,Sichuan University,Chengdu 610065,Sichuan Province,)
出处
《中国农村水利水电》
北大核心
2023年第8期128-134,共7页
China Rural Water and Hydropower
基金
国家自然科学基金联合基金项目(U2040219)。
关键词
雨滴溅蚀
非均匀沙
脉冲式
坡度
droplet sputtering
non-uniform sand
pulse type
slope
