The experiments and calculation indicate that the common Stokesformula is only suitable to the situation with small grain settling Reynold number.
实验及计算表明：常用的斯托克斯公式仅适应于颗粒沉降雷诺数较小的情况；
3
Otherwise there will be a large error between the value calculated by Stokesformula and the actual value under the condition of bigger sand grain and lower fluid viscosity.