Application of Wavelet Fractal Dimension Estimation in Dividing Flood Stages for Three Gorges Reservoir
Abstract Limit water level control improves water resources utilization efficiency without reducing flood control standard, while the premise is to divide the discharge series into a number of different flood stages. Db4 is selected as wavelet base, based on Mallat algorithm, put forward the model of wavelet dimension estimation method and calculated the fractal dimension of floods at the Yichang station, got the flood periods of Three Gorges reservoir. The results indicate that the method of wavelet dimension estimation can obtain the same result as traditional methods, and it has the merit of simplicity and stability. As a feasible and effective tool, the wavelet dimension estimation method is recommended in the applications of dividing flood periods.
Estimation of Fractal Dimension for Daily Flow Hydrograph
The methods for estimating fractal dimensions of daily flow hydrograph in a river are mainly presented. The resultshave shown that a box counting method is the best one among the five methods involved in the analysis.
Fractal dimensions of aggregates from shear devices
Average fractal dimensions of aggregates of fluorescent microspheres were measured as a function of mean shear rate and ionic strength using a new technique that relies on simultaneous measurement of size spectra in terms of aggregate length and solid volume. To demonstrate that changes in ionic strength produced changes in particle stickiness, the authors determined that collision efficiencies of a monodisperse suspension varied between 0.0016 and 0.37 when NaCl concentrations ranged from 0.05 to 0.8 M. Average fractal dimensions of D 1 = 1.11, D 2 = 1.85, and D 3 = 1.81, measured for aggregates produced under turbulent shear conditions using paddle mixers, were not a function of NaCl concentration.