葛赛 赵涛 吴思 吴洋锋

摘要：以矩形人工加糙渠道为研究对象，采用主成分分析支持向量机方法建立糙率系数预测模型。根据前期试验研究成果，选取佛汝德数Fr、绝对粗糙度Δ、渠道平均水深h、底坡i这四个主要影响因素，采用主成分分析方法提取两个主成分，获得影响糙率系数大小的综合性指标并用于支持向量机对数据的训练、测试及预测。研究结果显示：模型的训练集均方根误差RMSE为3.85×104、预测相关系数R为0.997，测试集均方根误差RMSE为5.37×104、预测相关系数R为0.992、预测相对误差小于5%。研究结果表明，基于主成分分析支持向量机所建模型适合人工渠道糙率系数的预测。

关键词：人工渠道；糙率系数；预测；主成分分析；支持向量机

中图分类号：TV135.3文献标志码：A文章编号：16721683（2018）03016906

Prediction model of roughness coefficient of artificially roughened channels based on

principal component analysissupport vector machine

GE Sai1，ZHAO Tao1，WU Si2，WU Yangfeng1

（1.College of Water Conservancy and Civil Engineering，Xinjiang Agricultural University，Urumqi 830052，China；

2.Yellow River Engineering Consulting Co.，Ltd.，Zhengzhou 450003，China）

Abstract：With the rectangular artificially roughened channel as the research object，we established a prediction model of roughness coefficient using the principal component analysissupport vector machine method.According to the preliminary experimental results，we selected four main influence factors： Froude number Fr，absolute roughness Δ，channel average water depth h，and bottom slope i.We used the principal component analysis method to obtain two main components，and obtained the comprehensive indexes influencing roughness coefficient，and used them for data training，testing，and prediction of the support vector machine.The research results showed that the RMSE and prediction correlation coefficient R of the training set were 385×104 and 0997 respectively，while those of the test set were and 0992 respectively.The relative error was less than 5%.The results showed that the model based on principal component analysissupport vector machine is suitable for predicting the roughness coefficient of artificial channels.

Key words：artificial channel；roughness coefficient；prediction；principal component analysis；support vector machine

明渠[1]以多种形式存在，明渠水流的水力计算广泛应用于水利、航运、城建和环境保护等多种行业的工程计算中[2]。其中，糙率系数的取值问题一直是明渠水流水力计算向精准计算方向发展的最大阻碍。糙率就其本义而讲，是衡量河床边壁粗糙程度对水流影响的一个系数，在一般情况下，边壁越粗糙，糙率系数就越大[35]。明渠根据其特性可分为天然渠道和人工渠道，人工渠道相对于天然渠道而言，过水断面的形状和尺寸以及表面的粗糙程度等沿程变化相对较小。采用人工加糙渠道进行糙率系数研究，进一步简化天然渠道复杂多变的水力要素并完善人工渠道单一边壁条件的不足，有助于客观全面的分析问题。……