A numerical procedure is proposed to estimate the velocity distribution in open channel flow, for engineering applications. A method based on the mixing length model and sub-division of the wetted surface, is modified to easily integrate a lateral distribution of roughness. Several friction models for vegetated or rough flows can be added, two of which have been tested. The numerical procedure was developed with a commercial software (Matlab) to ensure fast computation and possible coupling with 1D hydraulic models. The validation of the computation has been done with rectangular and compound channels with spatially distributed roughness. The usefulness of the method for ecohydraulics is demonstrated with two applications: box culvert design for fish passes and 1D modelling of mountain river flows for which experimental results from a laboratory scale-model is compared to predictions. The interest of a friction law calibrated with a real grain roughness size is put forward.

中文翻译：

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具有粗糙分布的明渠水流速度分布

提出了一种数值程序来估算明渠流中的速度分布，以用于工程应用。修改了基于混合长度模型和润湿表面细分的方法，以轻松整合粗糙度的横向分布。可以添加多个针对植被或粗糙流的摩擦模型，其中两个已经过测试。数值程序是使用商业软件（Matlab）开发的，以确保快速计算并可能与一维液压模型耦合。使用具有空间分布粗糙度的矩形和复合通道对计算进行了验证。两种方法证明了该方法对生态液压油的有效性：用于鱼道的箱涵设计和山区河流的一维建模，将实验室规模模型的实验结果与预测结果进行了比较。提出了用实际晶粒粗糙度尺寸校准的摩擦定律的兴趣。