坡面薄层水流滚波水力参数影响因素

Influence factors of hydraulic parameters of roll waves in overland flow

为探明滚波的演变过程及产生机理,采用定床阻力试验和超声波测量技术,研究了5种糙度、5种能坡、8种单宽流量下滚波水力参数的变化规律。结果表明:在固定断面,波速随单宽流量增加呈幂函数关系增大,相对波速反之,波高与相对波高先增大后减小;随糙度增加,波速减小,相对波速增大,波高及相对波高均减小;能坡对滚波的影响也与糙度有关,小糙度下,波速随能坡增加呈幂函数关系增大,相对波速反之,波高先增大后减小,相对波高持续增大;而大糙度下,随能坡增加,相对波速增加,波高整体不变,相对波高增加趋势变缓甚至有所减小。分析可知,相对波速、相对波高考虑了平均水力参数的变化,可以更好地反映各因素对滚波演变过程的影响。

In ascertain the evolution process and generating mechanism of roll waves,the variation rules of hydraulic parameters of roll waves under five kinds of roughness,five different energy slopes and eight unit discharges was studied by using a fixed bed test and ultrasonic measurement technology. The results showed that at the fixed section,the wave velocity increased as a power function with increasing unit discharges,while the relative wave velocity exhibited an opposite trend. The wave height and relative wave height first increased and then decreased as unit discharges increased. With the increase of roughness,wave velocity decreased while relative wave velocity increased. However,the wave height and relative wave height both decreased with an increasing roughness. The influence of energy slope on roll waves was also related to roughness. Under a small roughness,the wave velocity increased as a power function with the increasing energy slope while the decreasing power function between relative wave velocity and energy slope was found. Wave height first increased and then decreased while the relative wave height increased continuously. However,under a large roughness,the relative wave velocity increased and the wave height remained stable during the whole process with an increasing energy slope. In contrast,although the relative wave height increased first but this trend became less obvious and the height even decreased as energy slopes increased. Therefore,taking into account the influence of average hydraulic parameters were taken into account when adopting the relative wave velocity and relative wave height,which could better reflect how various factors affected the evolution process of roll waves.