论文部分内容阅读
通过理论分析和实测资料计算,阐释了黄河糙率异常现象并对其偏小的原因背景进行了剖析,认为导致黄河河槽糙率异常的主要原因,首要是套用清水定床条件下的时均流阻力计算公式,其次是计算所用水文实测资料难具代表性;同时指出曼宁公式无法良好适用于动床阻力计算,已有的动床阻力研究成果在理论上进展有限,也难有实用性强或精度高的计算公式;进一步通过阐述水深指数的影响因子及表达形式,提出了解决黄河河槽糙率异常的修正途径,使修正后糙率的点群关系得到改善,物理含义也得到保证。最后,根据本文方法修正后的花园口水文站糙率资料,建立了糙率同流量的经验关系式,进而可连同动床阻力修正公式预测不同来水来沙条件下的平均流速。黄河实测资料的检验结果表明其预测精度较高。
Through the theoretical analysis and measured data calculation, the phenomenon of the anomalous roughness of the Yellow River is explained and its reason of its small size is analyzed. The main reason that causes the roughness of the Yellow River fluvial anomaly is the time-average flow Resistance calculation formula, followed by the calculation of hydrological data used in the representativeness of the prototype; also pointed out that the Manning formula can not be well applied to the calculation of the dynamic bed resistance, the existing research results of the movable bed resistance in theory have limited progress, it is difficult to practical Or high precision calculation formula. Through further elaboration of the influence factors and expression form of water depth index, a modified approach to solve the roughness anomaly of the Yellow River trough is proposed. The corrected point-group relations of roughness are improved and the physical meaning is also guaranteed. Finally, based on the corrected roughness data of Huayuankou hydrological station, the empirical relation between roughness and flux is established, and then the average flow velocity under different conditions can be predicted along with the formula of the dynamic resistance correction. The test results of the Yellow River measured data show that the prediction accuracy is high.