Zhang et al. (2026) Longitudinal Mean Velocity and Turbulent Kinetic Energy Within an Emergent Canopy in Nonuniform Flows

⚠️ Warning: This summary was generated from the abstract only, as the full text was not available.

Identification

• Journal: Water Resources Research
• Year: 2026
• Date: 2026-03-01
• Authors: Yonggang Zhang, Ping Wang, Xiang Ke, Zheng Gong, Zi Wu
• DOI: 10.1029/2025wr040864

Research Groups

[Information not available in the provided abstract.]

Short Summary

This study investigates the longitudinal velocity and turbulent kinetic energy (TKE) dynamics in emergent canopies under streamwise varying flow conditions using laboratory flume experiments. It found that both time-mean longitudinal velocity and TKE significantly enhance downstream, and developed an analytical model revealing an effective power-law exponent of 2/3 between longitudinal TKE and mean velocity due to flow nonuniformity.

Objective

• To investigate the longitudinal velocity and turbulent kinetic energy (TKE) dynamics in emergent canopies under streamwise varying flow conditions.

Study Configuration

• Spatial Scale: Laboratory flume experiments representing emergent canopies (e.g., vegetated floodplain flows).
• Temporal Scale: Steady-state conditions for each experimental setup, focusing on time-mean longitudinal velocity and TKE dynamics.

Methodology and Data

• Models used: An analytical model based on the TKE budget was developed to predict longitudinal TKE evolution within the emergent canopy.
• Data sources: Laboratory flume experiments, systematically examining four vegetation densities and two flow discharge scenarios.

Main Results

• Both the time-mean longitudinal velocity and the turbulent kinetic energy (TKE) enhance significantly downstream along the emergent canopy.
• An analytical model was developed, based on the TKE budget, to predict the longitudinal TKE evolution within the emergent canopy.
• Flow nonuniformity introduces distinct terms into the TKE budget, including the streamwise-position dependent mean velocity, water surface gradient, and Froude number Fr(x).
• The developed model reveals an effective power-law exponent of 2/3 between longitudinal TKE and mean velocity, which differs from the canonical value of 2, attributed to residual energy contributions from the water surface gradient.

Contributions

• Provides a mechanistic framework for predicting the streamwise turbulence evolution in vegetated floodplain flows.
• Addresses a critical gap in ecohydraulic modeling by accounting for flow nonuniformity effects on turbulence.
• Identifies a novel power-law relationship (2/3 exponent) between longitudinal TKE and mean velocity in nonuniform vegetated flows, explaining the deviation from canonical values.

Funding

[Information not available in the provided abstract.]

Citation

@article{Zhang2026Longitudinal,
  author = {Zhang, Yonggang and Wang, Ping and Ke, Xiang and Gong, Zheng and Wu, Zi},
  title = {Longitudinal Mean Velocity and Turbulent Kinetic Energy Within an Emergent Canopy in Nonuniform Flows},
  journal = {Water Resources Research},
  year = {2026},
  doi = {10.1029/2025wr040864},
  url = {https://doi.org/10.1029/2025wr040864}
}