新型泥石流平均流速测量方法的实验研究

Experimental Study on a New Velocity Measurement Method for Debris Flow

泥石流流速是泥石流研究领域的重要指标,在泥石流水槽模拟实验中,现有测速方法主要针对泥石流表面流速和龙头流速。为了更好地测量泥石流断面的平均流速,提出了一种新型泥石流测速装置--圆周旋转式流速装置,通过实验对比了该装置与体积反算法、雷达测速仪法的测量效果,验证了该装置的有效性和适用性。水管冲击直接测试实验表明:该装置所测流速略小于由体积反算法所得的近似真实流速,这主要与装置本身的摩擦阻力有关,同时还证明了该装置可以达到较高的时间精度,0.2s时间段的速度值能较好地反应流体的平均流速。水槽实验的结果表明:该装置能连续测量断面平均流速,对流速随时间的变化和流体性质的变化均较为敏感,具有较好的灵敏度。

Velocity is a significant index in debris flow research. All the methods used in debris flow modeling experiments are focus on surface velocity or forefront part velocity of debris flow. In order to measure the crosssection velocity, a new method, that is, Circle Rotational Device(CRD), was proposed and studied in this research. Different measurement ways including volume back-calculation method, floating method and surface velocity radar(SVR) were compared with CRD to verify its effectiveness and applicability. According to the water pipe directly impact experiments, velocity measured by CRD was slightly smaller than the approximate real value calculated by volume back-calculation method, which was mainly due to the frictional resistance of the device itself. CRD was also tested to be able to achieve high time accuracy, for instance, 0.2 s is qualified to depict the average cross-section velocity. The results of the flume modeling tests demonstrated that CRD could continuously measure average cross-section velocity and was sensitive to the change of velocity with time and different types of fluid, which means this device has a good sensitivity.