分形理论在海滩剖面演化规律研究中的应用初探

Application of the fractal theory in the study of beach profile evolution

基于分形原理,通过波浪水槽试验,对波浪作用下的海滩剖面形态开展分形维数计算和分析,探究分形理论应用于海滩剖面演化规律研究的可能性。结果表明:海滩剖面分形维数可以用于描述海滩剖面形态的不规则程度和复杂性,分形维数越大,海滩剖面形态越复杂。同时,围绕波浪动力因素变化对海滩剖面分形维数的影响展开讨论,波浪类型、波高和水深的变化均会导致海滩剖面分形维数的改变,波浪类型和波高的变化对海滩剖面维数的影响更明显,而水深变化导致的波浪因素变化对海滩剖面分形维数的影响相对较小。研究发现随着波浪作用时间的增长,海滩剖面分形维数最终朝平衡方向发展。

Based on the fractal theory,the fractal dimension of beach profile under the wave actions had been calculated and analyzed through wave flume experimental study. The possibility of application of the fractal theory in the study of beach profile evolution had been investigated. Results show that the fractal dimension of beach profile can be used to describe the irregular degree and the complexity of the beach profile. The larger the fractal dimension is,the more irregular and more complex the beach profile are. Influences of wave dynamic factors on fractal dimensions of beach profile had also been discussed. Varies of wave type,wave height and still water depth could lead to the fractal dimensions of beach profile changes. Influences of wave type and wave height on the fractal dimension are more obvious,but variation of still water depth affects the fractal dimension of beach profile is relatively small. As the growth of the wave action time,the fractal dimension of beach profile will develop to balance eventually.