Study On Markov And Fractal Characteristics Of Velocities In Meandering Channel

As it is known, natural meandering river can be simulated by laboratorial curve glass flume whose flow field is more verisimilar while also more complicated for its strong three dimensional characters which caused by the walls of the channel. This article author believed that the traditional fitting of velocities along the relative water depth in meandering river is not scientific and not value for reference.In this paper, applying Acoustic Doppler Velocimeter(ADV) to sample the velocities under three different total water depths and different sections for obtaining real-time information of the flow field. Before the compute, should do preprocessing about the data recorded by the ADV, such as wiping out the‘burrs’and testing the normality of the data, etc.As the focus of this study, begin with the viewpoint of statistical theory of turbulence, utilize Markov process to systematically analyse the transition probabilities of fluctuation velocities of the experimental data which defined by UV-quadrant analysis method, and the results expound the bursting phenomenon in the boundary layer. In addition, the comparison of box-counting method, R/S method and local roughness method which are applied to evaluate the fractal dimensions of Weierstrass-Mandelbrot function and fractal Brownian motion indicates that the last one has an advantage in computing the fractal dimensions of turbulent velocities in open meandering channel, then use local roughness method to compute the velocities dimensions of three water depths and relative summary will be demonstrated in the paper.