明渠流动若干特性初探

解析定量计算了光滑边壁条件下明渠内部平均流和脉动流能量间的分配关系,得到了平均流粘性耗散能量、脉动流能量、脉动流取自平均流能量之间的关系表达式.分析了能谱的结构形式,从工程应用的角度初步勾勒了恒定流动光滑边壁条件下明渠内部能量分布的轮廓.讨论了壁面剪切流层内的流场结构和特性,研究了Navier-Stokes方程的标度变换等一些定量的指标,从标度和流速分布之间的相互关系入手,对这些指标及其间的相互关系进行了讨论.分析了二维平行壁面剪切流内部流动结构的机理和特性,指出能量传递和不同阶段的不同结构有关,能量耗散和扩散与共振和锁频密切相联系.从另一个角度阐释雷诺数的物理意义,以突出雷诺数和涡之间的关系,强调雷诺数是空间点和时间的函数.

Studies in Some Properties of Open Channel flow

Some properties of two dimensional open channel flow were studied.The energy distributing was calculated to show the energy exchanging relationship between mean flow and fluctuation flow.The viscous dissipative energy of mean flow,energy of fluctuating flow and energy of fluctuating flow taking from mean flow were calculated.The energy spectrum was explored.The profiles of energy distribution of steady open channel flow with hydraulic smooth wall was sketched from the viewpoint of practical engineering.The transformation laws of Navier-Stokes equation such as scaling etc were investigated and the relations between scaling and velocity distribution were discussed.The mechanism of two dimensional parallel wall shear flow was probed to show that not only energy transfer relates different structures corresponding to different levels of turburent exciting but also energy dissipating and diffusing closely connect with resonant vibration and frequency-locking,physical meaning of Reynold's number is illustrated in different viewpoints to emphasize the relationship between vortex and Reynold's number.It shows that Reynold's number is a function of spatial spot and time.