河流中低淹没度下刚性沉水植被阻力系数改进研究

Study of Resistance Coefficient of Rigid Vegetation in Low Submergence

准确评估植被阻力对预测植被影响下的河流流速分布具有重要意义。采用已有研究数据,验证了6种挺水植被阻力系数公式在刚性沉水植被流计算中的适用性,并在已有研究基础上考虑淹没度影响,针对低淹没度情形,提出了改进的阻力系数公式。结果表明,各公式平均计算精度接近,计算流速与实测流速相对误差均在10.20%~15.19%之间;改进阻力系数公式计算精度良好,公式计算流速与实测流速相对误差为3.40%,可用于植被层流速估算,适用范围为淹没度1<H/h_(v)<2且固体体积分数0<ϕ≤0.02。

It is important to accurately assess the additional resistance caused by vegetation to predict the velocity distribution under the influence of vegetation.Based on the experimental data,the applicability of the six kinds of resistance coefficient formulas in the calculation of submerged rigid vegetation flow was verified.Based on the previous research,the improved resistance coefficient formula was proposed for the low degree of inundation.The results show that the average accuracy of the formulas is close,and the relative error between the calculated velocity and the measured velocity is in the range of 10.20%-15.19%.The calculation accuracy of the improved resistance coefficient formula is good,and the relative error between the calculated velocity and the measured velocity is 3.40%.It can be used to estimate the velocity of vegetation layer in the range of 1<H/hv<2 and 0<ϕ≤0.02.