标准型异形椭圆断面正常水深和临界水深计算

针对标准型异形椭圆断面正常水深和临界水深的基本方程均为超越方程、无法直接求解的问题，在归纳标准型异形椭圆断面水力要素计算公式的基础上，通过引入量纲一参数和采用曲线分段优化拟合的分析方法，提出了求解标准型异形椭圆断面正常水深和临界水深的直接计算公式。误差分析结果表明，该断面正常水深和临界水深直接计算公式相对误差的绝对值最大分别为0.362%和0.288%，其适用范围及精度均能够满足工程应用的要求。

Calculation of normal depth and critical depth for standard-type heteromorphic elliptic section

Basic equations of normal and critical water depths for standard-type heteromorphic elliptic section are transcendental which cannot be solved directly. On the basis of summarizing the hydraulic factor calculation formulas of standard-type heteromorphic elliptic section, dimensionless parameters and the method of curve piecewise fitting optimization analysis were introduced to propose the explicit calculation formulas for solving the normal and critical water depth of standard-type heteromorphic elliptic section. The results of error analysis show that the absolute values of relative error of the normal and critical water depth formulas for a typical cross-section were less than 0. 362% and 0. 288%, respectively, which were within the common range in real engineering applications.