{"title":"年平均流量和宽深比对蜿蜒河道平面形态的长期演变影响","authors":"Xiaolong Song , Haijue Xu , Yuchuan Bai","doi":"10.1016/j.ijsrc.2023.11.003","DOIUrl":null,"url":null,"abstract":"<div><p>A depth-averaged linearized meander evolution model was used to numerically evaluate the spatiotemporal evolution of the meandering channel centerline in the plane at various mean annual flows and width–depth ratios for capturing the overall average trend of the meandering channel planform. This analysis was done to better understand the consistent responses of the river morphology to possible future tectonic and climatic changes. The computational cases included an idealized sine-generated meandering channel with a moderate maximum deflection angle and a typical natural meander for the Jiyun River in China. The study results showed phased development and response characteristics of the meandering channel centerline (to the mean annual flow), along with increases in the specified mean annual width (<em>B</em>)–depth (<em>H</em>) ratio (represented by <em>B</em>/<em>H</em>). First, the spatial meander straightening trend over time weakened during Phase 1 (<em>B</em>/<em>H</em> ≤ 16.5) and gradually changed to a meander developing trend during Phase 2 (16.5 < <em>B</em>/<em>H</em> ≤ 27) with an overall insensitivity to the flow magnitude. Second, starting from the downstream tail during Phase 3 (27 < <em>B</em>/<em>H</em> ≤ 28.9), the symmetric development form along the transverse direction (perpendicular to the mean flow direction) was disrupted, while flow effects were highlighted when the mean annual <em>B</em>/<em>H</em> exceeded 28. Finally, an obvious onset and jump process of the channel sensitivity in response to flow occurred during Phase 4 (28.9 < <em>B</em>/<em>H</em> ≤ 29.5). These event characteristics are very similar to the transition from laminar to turbulent flow in fluid mechanics. This study provides insights for more in-depth exploration of meandering mechanisms and technical support for effective river management.</p></div>","PeriodicalId":50290,"journal":{"name":"International Journal of Sediment Research","volume":"39 1","pages":"Pages 131-143"},"PeriodicalIF":3.5000,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1001627923000707/pdfft?md5=153064cc5dc93e37160f1c92af226fc2&pid=1-s2.0-S1001627923000707-main.pdf","citationCount":"0","resultStr":"{\"title\":\"Long-term evolution of meandering channel planforms in response to the mean annual flow and width–depth ratio\",\"authors\":\"Xiaolong Song , Haijue Xu , Yuchuan Bai\",\"doi\":\"10.1016/j.ijsrc.2023.11.003\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>A depth-averaged linearized meander evolution model was used to numerically evaluate the spatiotemporal evolution of the meandering channel centerline in the plane at various mean annual flows and width–depth ratios for capturing the overall average trend of the meandering channel planform. This analysis was done to better understand the consistent responses of the river morphology to possible future tectonic and climatic changes. The computational cases included an idealized sine-generated meandering channel with a moderate maximum deflection angle and a typical natural meander for the Jiyun River in China. The study results showed phased development and response characteristics of the meandering channel centerline (to the mean annual flow), along with increases in the specified mean annual width (<em>B</em>)–depth (<em>H</em>) ratio (represented by <em>B</em>/<em>H</em>). First, the spatial meander straightening trend over time weakened during Phase 1 (<em>B</em>/<em>H</em> ≤ 16.5) and gradually changed to a meander developing trend during Phase 2 (16.5 < <em>B</em>/<em>H</em> ≤ 27) with an overall insensitivity to the flow magnitude. Second, starting from the downstream tail during Phase 3 (27 < <em>B</em>/<em>H</em> ≤ 28.9), the symmetric development form along the transverse direction (perpendicular to the mean flow direction) was disrupted, while flow effects were highlighted when the mean annual <em>B</em>/<em>H</em> exceeded 28. Finally, an obvious onset and jump process of the channel sensitivity in response to flow occurred during Phase 4 (28.9 < <em>B</em>/<em>H</em> ≤ 29.5). These event characteristics are very similar to the transition from laminar to turbulent flow in fluid mechanics. This study provides insights for more in-depth exploration of meandering mechanisms and technical support for effective river management.</p></div>\",\"PeriodicalId\":50290,\"journal\":{\"name\":\"International Journal of Sediment Research\",\"volume\":\"39 1\",\"pages\":\"Pages 131-143\"},\"PeriodicalIF\":3.5000,\"publicationDate\":\"2024-02-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://www.sciencedirect.com/science/article/pii/S1001627923000707/pdfft?md5=153064cc5dc93e37160f1c92af226fc2&pid=1-s2.0-S1001627923000707-main.pdf\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"International Journal of Sediment Research\",\"FirstCategoryId\":\"93\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S1001627923000707\",\"RegionNum\":2,\"RegionCategory\":\"环境科学与生态学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"ENVIRONMENTAL SCIENCES\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"International Journal of Sediment Research","FirstCategoryId":"93","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1001627923000707","RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENVIRONMENTAL SCIENCES","Score":null,"Total":0}
Long-term evolution of meandering channel planforms in response to the mean annual flow and width–depth ratio
A depth-averaged linearized meander evolution model was used to numerically evaluate the spatiotemporal evolution of the meandering channel centerline in the plane at various mean annual flows and width–depth ratios for capturing the overall average trend of the meandering channel planform. This analysis was done to better understand the consistent responses of the river morphology to possible future tectonic and climatic changes. The computational cases included an idealized sine-generated meandering channel with a moderate maximum deflection angle and a typical natural meander for the Jiyun River in China. The study results showed phased development and response characteristics of the meandering channel centerline (to the mean annual flow), along with increases in the specified mean annual width (B)–depth (H) ratio (represented by B/H). First, the spatial meander straightening trend over time weakened during Phase 1 (B/H ≤ 16.5) and gradually changed to a meander developing trend during Phase 2 (16.5 < B/H ≤ 27) with an overall insensitivity to the flow magnitude. Second, starting from the downstream tail during Phase 3 (27 < B/H ≤ 28.9), the symmetric development form along the transverse direction (perpendicular to the mean flow direction) was disrupted, while flow effects were highlighted when the mean annual B/H exceeded 28. Finally, an obvious onset and jump process of the channel sensitivity in response to flow occurred during Phase 4 (28.9 < B/H ≤ 29.5). These event characteristics are very similar to the transition from laminar to turbulent flow in fluid mechanics. This study provides insights for more in-depth exploration of meandering mechanisms and technical support for effective river management.
期刊介绍:
International Journal of Sediment Research, the Official Journal of The International Research and Training Center on Erosion and Sedimentation and The World Association for Sedimentation and Erosion Research, publishes scientific and technical papers on all aspects of erosion and sedimentation interpreted in its widest sense.
The subject matter is to include not only the mechanics of sediment transport and fluvial processes, but also what is related to geography, geomorphology, soil erosion, watershed management, sedimentology, environmental and ecological impacts of sedimentation, social and economical effects of sedimentation and its assessment, etc. Special attention is paid to engineering problems related to sedimentation and erosion.