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一定尺度范围的紊流涡体会主导河流形态的发展,塑造出某一特定弯曲度的河段,这种涡体称之为“弯道造床涡体”;弯道造床涡体与弯道相互协调关系则表现为“河流的自适应特征”.在以上两个概念的基础上,本文以自然界U型河湾为背景,从理论上分析了常曲率河湾紊流拟序涡体结构的稳定与自适应特征.参照流体力学相关理论,将紊流拟序涡体结构看作一种扰动,计算了不同弯曲度情况下,河湾拟序涡体的扰动增长率和扰动波数响应范围;研究了不同尺度紊流结构对河湾参数的响应情况,解释了河湾得以保持的可能动力机理,为进一步研究河湾蠕动提供了理论基础.
A certain scale of turbulent eddies will dominate the development of river morphology and create a certain degree of curvature of the river, which is called the " On the basis of the above two concepts, based on the U-shaped river bay in nature, this paper theoretically analyzes the turbulent eddy current Structural stability and self-adaptive characteristics.According to the theory of fluid mechanics, the turbulence-programmed vortex structure is regarded as a kind of disturbance, and the growth rate of disturbance and wave number response The turbulence structures at different scales were studied in response to the parameters of the river bay, and the possible dynamic mechanism of the river bay was explained, which provided a theoretical basis for further study on the creep of the river bay.