Stability and self-adaption character of turbulence coherent structure in narrow-deep river bend

• DOI: 10.1007/s11431-012-4977-4
• Publication Date: 2012-08-11T10:48:00Z
• Authors: YuChuan Bai; ZiQing Ji; HaiJue Xu
• Keywords: 0207 environmental engineering; 02 engineering and technology

In a meandering river, a certain scale of turbulent vortex dominates the development of river morphology, making the river bend with s particular curvature. This kind of vortex is denoted as “bend-forming vortex”. The coordinated relationship of bend-forming vortex and meandering river channel is then known as “self-adaption feature” of rivers. With these two concepts, this paper investigated the stability and self-adaption character of coherent vortex in the U-shape river bend with a constant curvature. On the basis of fluid mechanics theory and in consideration of turbulent coherent vortex as disturbance, the growth rate and the wave number response range of coherent vortex in meandering rivers with different curvatures were calculated in this paper. Moreover, the responses of different scales of coherent turbulence structure to river bend parameters were analyzed to explain the mechanism of river bend maintenance. These methods could provide a theoretical basis for further investigation on river meandering.