低雷诺数壁面约束流动皮托管测速误差分析与校正

针对低雷诺数壁面约束流动中皮托管测速误差产生的两大主要影响因素——剪切速度与近壁效应，采用计算流体力学技术分别对其进行数值模拟，并研究各自引起的误差变化规律。数值模拟结果表明：虽然剪切速度引起的流线偏移规律与相关文献结论基本一致，但是数值结果预测的流线偏移量并不是一个渐近函数；近壁距离在5倍管径即出现较为明显的测量误差，并且发现近壁距离在1倍管径处出现误差的非单调性变化。最后通过将数值模拟结果与现有的修正方法进行对比，提出了更为合理的修正方程。
The numerical investigation of two main factors, velocity shear and wall proximity effect, which affects mean velocity measurement for low Reynolds number wall-bounded flow using Pitot tubes, was carried out. Their effects were separated through careful numerical simulation and cases were run for each of them respectively for error analysis. The simulation results show that: for velocity shear, the result of current work basically agrees with that of related literature, however, the non dimensional streamline shift does not asymptotically approach to a constant value; noticeable wall vicinity effect can be found within 5 tube diameters to the wall, and errors are decreasing within 1 tube diameter to the wall. Comparisons were made among the numerical solutions in this work and the corrections being used in the literature, and the new corrections based on simulation results of current work were given in the end.