【摘要】 在U形混凝土明渠内,采用声学多普勒点式流速仪(Vectrino)测量了不同流量下的瞬时流速,对明渠水流紊动的准周期、频率等水流紊动特性进行了定量的描述,对紊动强度、雷诺应力进行了较深入的分析计算。试验分析结果表明:①水流脉动具有大小不同的准周期。②水流瞬时流速概率分布近似符合正态分布。③各垂线纵向、垂向紊动强度自渠底向水面先减小后增大,横向紊动强度变化幅度较小。④纵向与横向雷诺切应力在y/h>0.5范围内近似为直线,y/h<0.5区域内近似为三角形分布。更多还原

【Abstract】 Using Acoustic Doppler point current meter(Vectrino),the instantaneous velocity at different measurement points under different flow rate were measured in U-shaped channel.The turbulent characteristics of flow,such as period,frequency,were described by means of quantitative analysis.And the turbulent intensities and Reynolds stresses were further analyzed and calculated. The experimental result indicate that:the velocity pulsing process had different quasi-periodic;the probability distribution of fluctuating velocity was approximately in the form of Gaussian curve;the longitudinal and vertical turbulent intensities on different perpendicular line was reduced initially then increased from bottom of channel to the surface,the range of turbulent intensities on transversal was small;Reynolds stresses on longitudinal and transversal distributed approximated straight line in the range of relative flow depth bigger than 0.5and triangular distribution when the relative flow depth was smaller than 0.5.更多还原