基于混合长理论垂线平均流速分析及应用

Analysis and Practice of Vertical Average Velocity Based on Mixed Length Theory

垂线流速测验作为影响流量测验精度的重要因子。基于混合长理论,以石牌站2021年多点法流速实测资料作为实践验证样本,对垂线流速测深点代表性及流速纵向与横向特征进行分析。分析结果显示:基于混合长理论推导垂线平均流速为距水面相对位置0.6处,该测验点位置具有代表性,实测资料证明了此推导的正确性,该相对位置点所测流速作为垂线平均流速具有代表性;平均流速沿垂线纵向分布特征表现为,流速值大小从相对水深0.0处向1.0处顺序递减;流速高峰值分布区域为水面至水下垂线1/5处,低峰值区域位于近河底处;垂速沿过洪断面横向分布特征为主槽水深最大处的起点距及附近为流速高峰值分布区域,流速横向沿程大小与平均水深的沿程变化趋势基本一致;流速低峰值分布与左右近岸边区域一致。

Vertical velocity measurement is an important factor affecting the accuracy of flow measurement.Based on the mixed length theory and the measured data of multi-point velocity in Shipai Station in 2021,the representativeness of vertical velocity sounding points and the vertical and horizontal characteristics of velocity are analyzed.The analysis results show that based on the mixed length theory,the vertical average velocity is 0.6 from the relative position of the water surface(after rounding),and the position of the test point is representative.The measured data prove the correctness of this derivation,and the velocity measured at the relative position is representative as the vertical average velocity;the longitudinal distribution of the average velocity along the vertical line shows that the value of the velocity decreases sequentially from 0.0 to 1.0 of the relative water depth;The distribution area of high peak velocity is one fifth of the vertical line from the water surface to the underwater,and the area of low peak velocity is near the river bottom;the horizontal distribution of vertical velocity along the flood discharge section is characterized by the starting point distance at and near the maximum water depth of the main channel,which is the distribution area of high peak velocity,and the horizontal variation trend of velocity is basically consistent with that of average water depth;the distribution of low peak velocity is similar to that of the left and right near the shore.