Formation and structure of wake flows after a rectangular vegetation patch

Yuan Heng Zhang; Huan Feng Duan; Xu Feng Yan

doi:10.3850/978-90-833476-1-5_iahr40wc-p1063-cd

Formation and structure of wake flows after a rectangular vegetation patch

Yuan Heng Zhang
, Huan Feng Duan
, Xu Feng Yan

Research output: Chapter in book / Conference proceeding › Conference article published in proceeding or book › Academic research › peer-review

Abstract

This research presents an experimental study on the impact of a center-channel rectangular vegetation patch under an aligned configuration of rigid and emergent stems on the flow adjustment and wake structure. A steady wake region with a length of L1 and a relatively low velocity (U₁) and turbulence forms after the patch, facilitating patch elongation. The interior adjustment length (L_a) in this study is observed to be proportional to the ratio of patch width (W) to patch density (Φ), i.e., W/Φ. Considering the cumulative effect induced by the patch length (L), a cumulative hydraulic resistance was developed based on the ratio of L to W (i.e, Φ×L W) to qualify the L₁ and U₁. It is observed that both steady wake length and steady wake velocity will be mitigated as the cumulative hydraulic resistance enhances, until the velocity starts to increase immediately downstream of the patch, performing like a solid obstruction, indicating the equilibrium state of the patch. Therefore, the expansion length will be shortened as the patch elongates downstream, which is an iterative process. The formula developed in this study helps to obtain a comprehensive understanding of the patch growth from its initial circular shape to a stable rectangular patch and the flow-vegetation-sediment interaction.

Original language	English
Title of host publication	Proceedings of the 40th IAHR World Congress
Editors	Helmut Habersack, Michael Tritthart, Lisa Waldenberger
Publisher	International Association for Hydro-Environment Engineering and Research (IAHR)
Pages	168-172
Number of pages	5
ISBN (Print)	9789083347615
DOIs	https://doi.org/10.3850/978-90-833476-1-5_iahr40wc-p1063-cd
Publication status	Published - 2023
Event	40th IAHR World Congress, 2023 - Vienna, Austria Duration: 21 Aug 2023 → 25 Aug 2023

Publication series

Name	Proceedings of the IAHR World Congress
ISSN (Print)	2521-7119
ISSN (Electronic)	2521-716X

Conference

Conference	40th IAHR World Congress, 2023
Country/Territory	Austria
City	Vienna
Period	21/08/23 → 25/08/23

Keywords

Aspect ratio
Density
Steady wake length
Steady wake velocity
Vegetation patch

ASJC Scopus subject areas

Engineering (miscellaneous)
Civil and Structural Engineering
Ocean Engineering
Water Science and Technology

More information

10.3850/978-90-833476-1-5_iahr40wc-p1063-cd

Cite this

Zhang, Y. H., Duan, H. F., & Yan, X. F. (2023). Formation and structure of wake flows after a rectangular vegetation patch. In H. Habersack, M. Tritthart, & L. Waldenberger (Eds.), Proceedings of the 40th IAHR World Congress (pp. 168-172). (Proceedings of the IAHR World Congress). International Association for Hydro-Environment Engineering and Research (IAHR). https://doi.org/10.3850/978-90-833476-1-5_iahr40wc-p1063-cd

Zhang, Yuan Heng ; Duan, Huan Feng ; Yan, Xu Feng. / Formation and structure of wake flows after a rectangular vegetation patch. Proceedings of the 40th IAHR World Congress. editor / Helmut Habersack ; Michael Tritthart ; Lisa Waldenberger. International Association for Hydro-Environment Engineering and Research (IAHR), 2023. pp. 168-172 (Proceedings of the IAHR World Congress).

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title = "Formation and structure of wake flows after a rectangular vegetation patch",

abstract = "This research presents an experimental study on the impact of a center-channel rectangular vegetation patch under an aligned configuration of rigid and emergent stems on the flow adjustment and wake structure. A steady wake region with a length of L1 and a relatively low velocity (U1) and turbulence forms after the patch, facilitating patch elongation. The interior adjustment length (La) in this study is observed to be proportional to the ratio of patch width (W) to patch density (Φ), i.e., W/Φ. Considering the cumulative effect induced by the patch length (L), a cumulative hydraulic resistance was developed based on the ratio of L to W (i.e, Φ×L W) to qualify the L1 and U1. It is observed that both steady wake length and steady wake velocity will be mitigated as the cumulative hydraulic resistance enhances, until the velocity starts to increase immediately downstream of the patch, performing like a solid obstruction, indicating the equilibrium state of the patch. Therefore, the expansion length will be shortened as the patch elongates downstream, which is an iterative process. The formula developed in this study helps to obtain a comprehensive understanding of the patch growth from its initial circular shape to a stable rectangular patch and the flow-vegetation-sediment interaction.",

keywords = "Aspect ratio, Density, Steady wake length, Steady wake velocity, Vegetation patch",

author = "Zhang, \{Yuan Heng\} and Duan, \{Huan Feng\} and Yan, \{Xu Feng\}",

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Zhang, YH, Duan, HF & Yan, XF 2023, Formation and structure of wake flows after a rectangular vegetation patch. in H Habersack, M Tritthart & L Waldenberger (eds), Proceedings of the 40th IAHR World Congress. Proceedings of the IAHR World Congress, International Association for Hydro-Environment Engineering and Research (IAHR), pp. 168-172, 40th IAHR World Congress, 2023, Vienna, Austria, 21/08/23. https://doi.org/10.3850/978-90-833476-1-5_iahr40wc-p1063-cd

Formation and structure of wake flows after a rectangular vegetation patch. / Zhang, Yuan Heng; Duan, Huan Feng; Yan, Xu Feng.
Proceedings of the 40th IAHR World Congress. ed. / Helmut Habersack; Michael Tritthart; Lisa Waldenberger. International Association for Hydro-Environment Engineering and Research (IAHR), 2023. p. 168-172 (Proceedings of the IAHR World Congress).

Research output: Chapter in book / Conference proceeding › Conference article published in proceeding or book › Academic research › peer-review

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AU - Zhang, Yuan Heng

AU - Duan, Huan Feng

AU - Yan, Xu Feng

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N2 - This research presents an experimental study on the impact of a center-channel rectangular vegetation patch under an aligned configuration of rigid and emergent stems on the flow adjustment and wake structure. A steady wake region with a length of L1 and a relatively low velocity (U1) and turbulence forms after the patch, facilitating patch elongation. The interior adjustment length (La) in this study is observed to be proportional to the ratio of patch width (W) to patch density (Φ), i.e., W/Φ. Considering the cumulative effect induced by the patch length (L), a cumulative hydraulic resistance was developed based on the ratio of L to W (i.e, Φ×L W) to qualify the L1 and U1. It is observed that both steady wake length and steady wake velocity will be mitigated as the cumulative hydraulic resistance enhances, until the velocity starts to increase immediately downstream of the patch, performing like a solid obstruction, indicating the equilibrium state of the patch. Therefore, the expansion length will be shortened as the patch elongates downstream, which is an iterative process. The formula developed in this study helps to obtain a comprehensive understanding of the patch growth from its initial circular shape to a stable rectangular patch and the flow-vegetation-sediment interaction.

AB - This research presents an experimental study on the impact of a center-channel rectangular vegetation patch under an aligned configuration of rigid and emergent stems on the flow adjustment and wake structure. A steady wake region with a length of L1 and a relatively low velocity (U1) and turbulence forms after the patch, facilitating patch elongation. The interior adjustment length (La) in this study is observed to be proportional to the ratio of patch width (W) to patch density (Φ), i.e., W/Φ. Considering the cumulative effect induced by the patch length (L), a cumulative hydraulic resistance was developed based on the ratio of L to W (i.e, Φ×L W) to qualify the L1 and U1. It is observed that both steady wake length and steady wake velocity will be mitigated as the cumulative hydraulic resistance enhances, until the velocity starts to increase immediately downstream of the patch, performing like a solid obstruction, indicating the equilibrium state of the patch. Therefore, the expansion length will be shortened as the patch elongates downstream, which is an iterative process. The formula developed in this study helps to obtain a comprehensive understanding of the patch growth from its initial circular shape to a stable rectangular patch and the flow-vegetation-sediment interaction.

KW - Aspect ratio

KW - Density

KW - Steady wake length

KW - Steady wake velocity

KW - Vegetation patch

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SN - 9789083347615

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SP - 168

EP - 172

BT - Proceedings of the 40th IAHR World Congress

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A2 - Tritthart, Michael

A2 - Waldenberger, Lisa

PB - International Association for Hydro-Environment Engineering and Research (IAHR)

T2 - 40th IAHR World Congress, 2023

Y2 - 21 August 2023 through 25 August 2023

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Zhang YH, Duan HF, Yan XF. Formation and structure of wake flows after a rectangular vegetation patch. In Habersack H, Tritthart M, Waldenberger L, editors, Proceedings of the 40th IAHR World Congress. International Association for Hydro-Environment Engineering and Research (IAHR). 2023. p. 168-172. (Proceedings of the IAHR World Congress). doi: 10.3850/978-90-833476-1-5_iahr40wc-p1063-cd

Formation and structure of wake flows after a rectangular vegetation patch

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