中国地理科学 ›› 2017, Vol. 27 ›› Issue (4): 577-588.doi: 10.1007/s11769-017-0888-4

• 论文 • 上一篇    下一篇

Analytical Models for Velocity Distributions in Compound Channels with Emerged and Submerged Vegetated Floodplains

ZHANG Mingwu1,2, JIANG Chunbo2, HUANG Heqing3, Gerald Charles NANSON4, CHEN Zhengbing2, YAO Wenyi1   

  1. 1. Yellow River Institute of Hydraulic Research, Yellow River Conservancy Commission, Zhengzhou 450003, China;
    2. State Key Laboratory of Hydroscience and Engineering, Department of Hydraulics, Tsinghua University, Beijing 100084, China;
    3. Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China;
    4. School of Earth and Environmental Sciences, University of Wollongong, Wollongong 2522, Australia
  • 收稿日期:2015-12-28 修回日期:2016-02-17 出版日期:2017-08-27 发布日期:2017-06-30
  • 通讯作者: ZHANG Mingwu.E-mail:thuzmw08@126.com E-mail:thuzmw08@126.com
  • 基金资助:

    Under the auspices of National Basic Research Program of China (No. 2011CB403303), National Key Research and Development Program of China (No. 2016YFC0402408-5), National Natural Science Foundation of China (No. 51179181, 40788001)

Analytical Models for Velocity Distributions in Compound Channels with Emerged and Submerged Vegetated Floodplains

ZHANG Mingwu1,2, JIANG Chunbo2, HUANG Heqing3, Gerald Charles NANSON4, CHEN Zhengbing2, YAO Wenyi1   

  1. 1. Yellow River Institute of Hydraulic Research, Yellow River Conservancy Commission, Zhengzhou 450003, China;
    2. State Key Laboratory of Hydroscience and Engineering, Department of Hydraulics, Tsinghua University, Beijing 100084, China;
    3. Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China;
    4. School of Earth and Environmental Sciences, University of Wollongong, Wollongong 2522, Australia
  • Received:2015-12-28 Revised:2016-02-17 Online:2017-08-27 Published:2017-06-30
  • Contact: ZHANG Mingwu.E-mail:thuzmw08@126.com E-mail:thuzmw08@126.com
  • Supported by:

    Under the auspices of National Basic Research Program of China (No. 2011CB403303), National Key Research and Development Program of China (No. 2016YFC0402408-5), National Natural Science Foundation of China (No. 51179181, 40788001)

摘要:

The lateral distributions of depth-averaged velocity in open compound channels with emerged and submerged vegetated floodplains were analyzed based on the analytical solution of the depth-integrated Reynolds-Averaged Navier-Stokes equation with a term to account for the effects of vegetation. The three cases considered for open channels were two-stage rectangular channel with emerged vegetated floodplain, rectangular channel with submerged vegetated corner, and two-stage rectangular channel with submerged vegetated floodplain, respectively. To predict the depth-averaged velocity with submerged vegetated floodplains, we proposed a new method based on a two-layer approach where flow above and through the vegetation layer was described separately. Moreover, further experiments in the two-stage rectangular channel with submerged vegetated floodplain were carried out to verify the results. The analytical solutions of the cases indicated that the corresponding analytical depth-averaged velocity distributions agree well with the simulated and experimental prediction. The analytical solutions of the cases with theoretical foundation and without programming calculation were reasonable and applicable, which were more convenient than numerical simulations. The analytical solutions provided a way for future researches to solve the problems of submerged vegetation and discontinuous phenomenon of depth-averaged velocity at the stage point for compound channels. Understanding the hydraulics of flow in compound channels with vegetated floodplains is very important for supporting the management of fluvial processes.

关键词: compound channel, velocity distribution, vegetated floodplain, two-stage rectangular channel, analytical solution

Abstract:

The lateral distributions of depth-averaged velocity in open compound channels with emerged and submerged vegetated floodplains were analyzed based on the analytical solution of the depth-integrated Reynolds-Averaged Navier-Stokes equation with a term to account for the effects of vegetation. The three cases considered for open channels were two-stage rectangular channel with emerged vegetated floodplain, rectangular channel with submerged vegetated corner, and two-stage rectangular channel with submerged vegetated floodplain, respectively. To predict the depth-averaged velocity with submerged vegetated floodplains, we proposed a new method based on a two-layer approach where flow above and through the vegetation layer was described separately. Moreover, further experiments in the two-stage rectangular channel with submerged vegetated floodplain were carried out to verify the results. The analytical solutions of the cases indicated that the corresponding analytical depth-averaged velocity distributions agree well with the simulated and experimental prediction. The analytical solutions of the cases with theoretical foundation and without programming calculation were reasonable and applicable, which were more convenient than numerical simulations. The analytical solutions provided a way for future researches to solve the problems of submerged vegetation and discontinuous phenomenon of depth-averaged velocity at the stage point for compound channels. Understanding the hydraulics of flow in compound channels with vegetated floodplains is very important for supporting the management of fluvial processes.

Key words: compound channel, velocity distribution, vegetated floodplain, two-stage rectangular channel, analytical solution