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Title: Modeling Intrajunction Dispersion at a Well-Mixed Tidal River Junction

In this paper, the relative importance of small-scale, intrajunction flow features such as shear layers, separation zones, and secondary flows on dispersion in a well-mixed tidal river junction is explored. A fully nonlinear, nonhydrostatic, and unstructured three-dimensional (3D) model is used to resolve supertidal dispersion via scalar transport at a well-mixed tidal river junction. Mass transport simulated in the junction is compared against predictions using a simple node-channel model to quantify the effects of small-scale, 3D intrajunction flow features on mixing and dispersion. The effects of three-dimensionality are demonstrated by quantifying the difference between two-dimensional (2D) and 3D model results. An intermediate 3D model that does not resolve the secondary circulation or the recirculating flow at the junction is also compared to the 3D model to quantify the relative sensitivity of mixing on intrajunction flow features. Resolution of complex flow features simulated by the full 3D model is not always necessary because mixing is primarily governed by bulk flow splitting due to the confluence–diffluence cycle. Finally, results in 3D are comparable to the 2D case for many flow pathways simulated, suggesting that 2D modeling may be reasonable for nonstratified and predominantly hydrostatic flows through relatively straight junctions, but not necessarilymore » for the full junction network.« less
Authors:
 [1] ;  [2] ;  [2] ;  [2] ;  [2] ;  [2]
  1. Stanford Univ., CA (United States). Dept. of Civil and Environmental Engineering; Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Climate, Ocean and Sea Ice Modeling (T-3) Group
  2. Stanford Univ., CA (United States). Dept. of Civil and Environmental Engineering
Publication Date:
Report Number(s):
LA-UR-15-27903
Journal ID: ISSN 0733-9429
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Journal of Hydraulic Engineering
Additional Journal Information:
Journal Volume: 142; Journal Issue: 8; Journal ID: ISSN 0733-9429
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE; Dept. of Defense (DoD) (United States). National Defense Science and Engineering Graduate Fellowship (NDSEG) Program
Country of Publication:
United States
Language:
English
Subject:
97 MATHEMATICS AND COMPUTING; 58 GEOSCIENCES; Planetary Sciences
OSTI Identifier:
1335599

Wolfram, Phillip J., Fringer, Oliver B., Monsen, Nancy E., Gleichauf, Karla T., Fong, Derek A., and Monismith, Stephen G.. Modeling Intrajunction Dispersion at a Well-Mixed Tidal River Junction. United States: N. p., Web. doi:10.1061/(ASCE)HY.1943-7900.0001108.
Wolfram, Phillip J., Fringer, Oliver B., Monsen, Nancy E., Gleichauf, Karla T., Fong, Derek A., & Monismith, Stephen G.. Modeling Intrajunction Dispersion at a Well-Mixed Tidal River Junction. United States. doi:10.1061/(ASCE)HY.1943-7900.0001108.
Wolfram, Phillip J., Fringer, Oliver B., Monsen, Nancy E., Gleichauf, Karla T., Fong, Derek A., and Monismith, Stephen G.. 2016. "Modeling Intrajunction Dispersion at a Well-Mixed Tidal River Junction". United States. doi:10.1061/(ASCE)HY.1943-7900.0001108. https://www.osti.gov/servlets/purl/1335599.
@article{osti_1335599,
title = {Modeling Intrajunction Dispersion at a Well-Mixed Tidal River Junction},
author = {Wolfram, Phillip J. and Fringer, Oliver B. and Monsen, Nancy E. and Gleichauf, Karla T. and Fong, Derek A. and Monismith, Stephen G.},
abstractNote = {In this paper, the relative importance of small-scale, intrajunction flow features such as shear layers, separation zones, and secondary flows on dispersion in a well-mixed tidal river junction is explored. A fully nonlinear, nonhydrostatic, and unstructured three-dimensional (3D) model is used to resolve supertidal dispersion via scalar transport at a well-mixed tidal river junction. Mass transport simulated in the junction is compared against predictions using a simple node-channel model to quantify the effects of small-scale, 3D intrajunction flow features on mixing and dispersion. The effects of three-dimensionality are demonstrated by quantifying the difference between two-dimensional (2D) and 3D model results. An intermediate 3D model that does not resolve the secondary circulation or the recirculating flow at the junction is also compared to the 3D model to quantify the relative sensitivity of mixing on intrajunction flow features. Resolution of complex flow features simulated by the full 3D model is not always necessary because mixing is primarily governed by bulk flow splitting due to the confluence–diffluence cycle. Finally, results in 3D are comparable to the 2D case for many flow pathways simulated, suggesting that 2D modeling may be reasonable for nonstratified and predominantly hydrostatic flows through relatively straight junctions, but not necessarily for the full junction network.},
doi = {10.1061/(ASCE)HY.1943-7900.0001108},
journal = {Journal of Hydraulic Engineering},
number = 8,
volume = 142,
place = {United States},
year = {2016},
month = {8}
}