Wave Boundary Layer Hydrodynamics and Sheet Flow Properties under Large-Scale Plunging-Type Breaking Waves

G. Fromant (Corresponding Author), D. Hurther, J. van der Zanden, D. A. Van der A, I. Cáceres, T. O'Donoghue, J. S. Ribberink

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Wave Boundary Layer (WBL) dynamics are measured with an Acoustic Concentration & Velocity Profiler (ACVP) across the sheet flow dominated wave breaking region of regular large-scale waves breaking as a plunger over a developing breaker bar. Acoustic sheet flow measurements are first evaluated quantitatively in comparison to Conductivity Concentration Meter (CCM+) data used as a reference. The near-bed orbital velocity field exhibits expected behaviours in terms of wave shape, intra-wave WBL thickness and velocity phase leads. The observed fully turbulent flow regime all across the studied wave breaking region supports the model-predicted transformation of free-stream velocity asymmetry into near-bed velocity skewness inside the WBL. Intra-wave concentration dynamics reveal the existence of a lower pick-up layer and an upper sheet flow layer similar to skewed oscillatory sheet flows, and with similar characteristics in terms of erosion depth and sheet flow layer thickness. Compared to the shoaling region, differences in terms of sheet flow and hydrodynamic properties of the flow are observed at the plunge point, attributed to the locally-enhanced wave breaker turbulence. The ACVP-measured total sheet flow transport rate is decomposed into its current-, wave- and turbulence-driven components. In the shoaling region, the sand transport is found to be fully dominated by the onshore skewed wave-driven component with negligible phase lag effects. In the outer surf zone, the total net flux exhibits a 3-layer vertical structure typical of skewed oscillatory sheet flows. However, in the present experiments this structure originates from offshore-directed undertow-driven flux, rather than from phase lag effects.
Original languageEnglish
Pages (from-to)75-98
Number of pages24
JournalJournal of Geophysical Research: Oceans
Volume124
Issue number1
Early online date3 Jan 2019
DOIs
Publication statusPublished - Jan 2019

Fingerprint

sheet flow
breaking wave
boundary layer
hydrodynamics
wave breaking
oscillating flow
acoustics
turbulence
undertow
surf zone
flow measurement
skewness
profiler
phase velocity
turbulent flow
asymmetry
conductivity
erosion
sand

Keywords

  • wave breaking
  • sheet flow
  • coastal sediment transport
  • wave hydrodynamics
  • ACVP
  • CCM

ASJC Scopus subject areas

  • Forestry
  • Aquatic Science
  • Soil Science
  • Water Science and Technology
  • Earth-Surface Processes
  • Geochemistry and Petrology
  • Geophysics
  • Oceanography
  • Palaeontology
  • Ecology
  • Space and Planetary Science
  • Earth and Planetary Sciences (miscellaneous)
  • Atmospheric Science

Cite this

Wave Boundary Layer Hydrodynamics and Sheet Flow Properties under Large-Scale Plunging-Type Breaking Waves. / Fromant, G. (Corresponding Author); Hurther, D.; van der Zanden, J.; Van der A, D. A.; Cáceres, I.; O'Donoghue, T.; Ribberink, J. S.

In: Journal of Geophysical Research: Oceans, Vol. 124, No. 1, 01.2019, p. 75-98.

Research output: Contribution to journalArticle

Fromant, G. ; Hurther, D. ; van der Zanden, J. ; Van der A, D. A. ; Cáceres, I. ; O'Donoghue, T. ; Ribberink, J. S. / Wave Boundary Layer Hydrodynamics and Sheet Flow Properties under Large-Scale Plunging-Type Breaking Waves. In: Journal of Geophysical Research: Oceans. 2019 ; Vol. 124, No. 1. pp. 75-98.
@article{009cbb0de3b547f89eb7bc179e3b3be5,
title = "Wave Boundary Layer Hydrodynamics and Sheet Flow Properties under Large-Scale Plunging-Type Breaking Waves",
abstract = "Wave Boundary Layer (WBL) dynamics are measured with an Acoustic Concentration & Velocity Profiler (ACVP) across the sheet flow dominated wave breaking region of regular large-scale waves breaking as a plunger over a developing breaker bar. Acoustic sheet flow measurements are first evaluated quantitatively in comparison to Conductivity Concentration Meter (CCM+) data used as a reference. The near-bed orbital velocity field exhibits expected behaviours in terms of wave shape, intra-wave WBL thickness and velocity phase leads. The observed fully turbulent flow regime all across the studied wave breaking region supports the model-predicted transformation of free-stream velocity asymmetry into near-bed velocity skewness inside the WBL. Intra-wave concentration dynamics reveal the existence of a lower pick-up layer and an upper sheet flow layer similar to skewed oscillatory sheet flows, and with similar characteristics in terms of erosion depth and sheet flow layer thickness. Compared to the shoaling region, differences in terms of sheet flow and hydrodynamic properties of the flow are observed at the plunge point, attributed to the locally-enhanced wave breaker turbulence. The ACVP-measured total sheet flow transport rate is decomposed into its current-, wave- and turbulence-driven components. In the shoaling region, the sand transport is found to be fully dominated by the onshore skewed wave-driven component with negligible phase lag effects. In the outer surf zone, the total net flux exhibits a 3-layer vertical structure typical of skewed oscillatory sheet flows. However, in the present experiments this structure originates from offshore-directed undertow-driven flux, rather than from phase lag effects.",
keywords = "wave breaking, sheet flow, coastal sediment transport, wave hydrodynamics, ACVP, CCM",
author = "G. Fromant and D. Hurther and {van der Zanden}, J. and {Van der A}, {D. A.} and I. C{\'a}ceres and T. O'Donoghue and Ribberink, {J. S.}",
note = "The authors wish to thank the staff of CIEMLAB, in particular Joaquim Sospedra, Oscar Galego and Ricardo Torres, for their hospitality and hard work during the experimental campaign. This research was funded by the European Community’s Horizon 2020 Programme through the Integrated Infrastructure Initiative HYDRALAB+ COMPLEX (no. 654110), the French DGA funded ANR Astrid Maturation project MESURE (no. ANR-16- ASMA-0005-01) and the SINBAD project funded by STW (12058) in the Netherlands and by EPSRC (EP/J00507X/1, EPJ005541/1) in the UK. Data of this study are available at U. Twente repository doi (10.4121/uuid:753f1d84-36e5-47fa-b74b-55c288545b9b). Comments and remarks raised by the two anonymous reviewers helped to improve the quality of the paper.",
year = "2019",
month = "1",
doi = "10.1029/2018JC014406",
language = "English",
volume = "124",
pages = "75--98",
journal = "Journal of Geophysical Research: Oceans",
issn = "2169-9275",
number = "1",

}

TY - JOUR

T1 - Wave Boundary Layer Hydrodynamics and Sheet Flow Properties under Large-Scale Plunging-Type Breaking Waves

AU - Fromant, G.

AU - Hurther, D.

AU - van der Zanden, J.

AU - Van der A, D. A.

AU - Cáceres, I.

AU - O'Donoghue, T.

AU - Ribberink, J. S.

N1 - The authors wish to thank the staff of CIEMLAB, in particular Joaquim Sospedra, Oscar Galego and Ricardo Torres, for their hospitality and hard work during the experimental campaign. This research was funded by the European Community’s Horizon 2020 Programme through the Integrated Infrastructure Initiative HYDRALAB+ COMPLEX (no. 654110), the French DGA funded ANR Astrid Maturation project MESURE (no. ANR-16- ASMA-0005-01) and the SINBAD project funded by STW (12058) in the Netherlands and by EPSRC (EP/J00507X/1, EPJ005541/1) in the UK. Data of this study are available at U. Twente repository doi (10.4121/uuid:753f1d84-36e5-47fa-b74b-55c288545b9b). Comments and remarks raised by the two anonymous reviewers helped to improve the quality of the paper.

PY - 2019/1

Y1 - 2019/1

N2 - Wave Boundary Layer (WBL) dynamics are measured with an Acoustic Concentration & Velocity Profiler (ACVP) across the sheet flow dominated wave breaking region of regular large-scale waves breaking as a plunger over a developing breaker bar. Acoustic sheet flow measurements are first evaluated quantitatively in comparison to Conductivity Concentration Meter (CCM+) data used as a reference. The near-bed orbital velocity field exhibits expected behaviours in terms of wave shape, intra-wave WBL thickness and velocity phase leads. The observed fully turbulent flow regime all across the studied wave breaking region supports the model-predicted transformation of free-stream velocity asymmetry into near-bed velocity skewness inside the WBL. Intra-wave concentration dynamics reveal the existence of a lower pick-up layer and an upper sheet flow layer similar to skewed oscillatory sheet flows, and with similar characteristics in terms of erosion depth and sheet flow layer thickness. Compared to the shoaling region, differences in terms of sheet flow and hydrodynamic properties of the flow are observed at the plunge point, attributed to the locally-enhanced wave breaker turbulence. The ACVP-measured total sheet flow transport rate is decomposed into its current-, wave- and turbulence-driven components. In the shoaling region, the sand transport is found to be fully dominated by the onshore skewed wave-driven component with negligible phase lag effects. In the outer surf zone, the total net flux exhibits a 3-layer vertical structure typical of skewed oscillatory sheet flows. However, in the present experiments this structure originates from offshore-directed undertow-driven flux, rather than from phase lag effects.

AB - Wave Boundary Layer (WBL) dynamics are measured with an Acoustic Concentration & Velocity Profiler (ACVP) across the sheet flow dominated wave breaking region of regular large-scale waves breaking as a plunger over a developing breaker bar. Acoustic sheet flow measurements are first evaluated quantitatively in comparison to Conductivity Concentration Meter (CCM+) data used as a reference. The near-bed orbital velocity field exhibits expected behaviours in terms of wave shape, intra-wave WBL thickness and velocity phase leads. The observed fully turbulent flow regime all across the studied wave breaking region supports the model-predicted transformation of free-stream velocity asymmetry into near-bed velocity skewness inside the WBL. Intra-wave concentration dynamics reveal the existence of a lower pick-up layer and an upper sheet flow layer similar to skewed oscillatory sheet flows, and with similar characteristics in terms of erosion depth and sheet flow layer thickness. Compared to the shoaling region, differences in terms of sheet flow and hydrodynamic properties of the flow are observed at the plunge point, attributed to the locally-enhanced wave breaker turbulence. The ACVP-measured total sheet flow transport rate is decomposed into its current-, wave- and turbulence-driven components. In the shoaling region, the sand transport is found to be fully dominated by the onshore skewed wave-driven component with negligible phase lag effects. In the outer surf zone, the total net flux exhibits a 3-layer vertical structure typical of skewed oscillatory sheet flows. However, in the present experiments this structure originates from offshore-directed undertow-driven flux, rather than from phase lag effects.

KW - wave breaking

KW - sheet flow

KW - coastal sediment transport

KW - wave hydrodynamics

KW - ACVP

KW - CCM

UR - http://www.scopus.com/inward/record.url?scp=85059581948&partnerID=8YFLogxK

UR - http://www.mendeley.com/research/wave-boundary-layer-hydrodynamics-sheet-flow-properties-under-largescale-plungingtype-breaking-waves

UR - https://doi.org/10.1029/2018JC014406

U2 - 10.1029/2018JC014406

DO - 10.1029/2018JC014406

M3 - Article

VL - 124

SP - 75

EP - 98

JO - Journal of Geophysical Research: Oceans

JF - Journal of Geophysical Research: Oceans

SN - 2169-9275

IS - 1

ER -