流沙沙漏视重变化现象的研究

Study on the Phenomenon of Apparent Weight Change of Quicksand Hourglass

沙漏在流沙的过程中,其视重呈先下降而后上升的趋势,从理论角度分析了这一现象产生的原因,并计算出了沙漏系统的视重随沙子初始下落高度、出口沙子质量流率等参量变化的定量关系.实验结果印证了理论预测的视重曲线的趋势、曲线峰值大小与初始沙子总质量无关,而与沙子流出的高度有关等结论.实验中还发现一些与理论预测结果不同的地方,如沙子触碰底面后稳定下落时为超重状态,即此时的视重比沙漏系统的初始重量要大,这与沙子流出上容器出口时的初速度有关,基于此又对理论模型进行了进一步修正,解释了实验结果与理论预测的差异.

When the sand in an hourglass is flowing, the apparent weight of the hourglass first decreases and then rises. This paper analyzes the causes of this phenomenon from a theoretical perspective, and calculates the quantitative relationship between the apparent weight of the hourglass system and the change of parameters such as the initial falling height of sand and the flow rate of sand mass at the outlet. The experimental results confirmed the trend and peak value of the curve predicted by the theory which the latter has nothing to do with the initial mass of sand, but will be influenced by the height of the sand outflow. Experimental results also shows something different with the theoretical prediction, such as the apparent weight of the stability flow of sand is bigger than the initial weight of the hourglass system, it has to do with the initial velocity of sand flow, based on this, the theoretical model is further modified, explains the differences between the experimental results and theoretical prediction.