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  1. Article ; Online: The Bottom Boundary Layer.

    Trowbridge, John H / Lentz, Steven J

    Annual review of marine science

    2018  Volume 10, Page(s) 397–420

    Abstract: The oceanic bottom boundary layer extracts energy and momentum from the overlying flow, mediates the fate of near-bottom substances, and generates bedforms that retard the flow and affect benthic processes. The bottom boundary layer is forced by winds, ... ...

    Abstract The oceanic bottom boundary layer extracts energy and momentum from the overlying flow, mediates the fate of near-bottom substances, and generates bedforms that retard the flow and affect benthic processes. The bottom boundary layer is forced by winds, waves, tides, and buoyancy and is influenced by surface waves, internal waves, and stratification by heat, salt, and suspended sediments. This review focuses on the coastal ocean. The main points are that (a) classical turbulence concepts and modern turbulence parameterizations provide accurate representations of the structure and turbulent fluxes under conditions in which the underlying assumptions hold, (b) modern sensors and analyses enable high-quality direct or near-direct measurements of the turbulent fluxes and dissipation rates, and
    MeSH term(s) Geologic Sediments/chemistry ; Hydrodynamics ; Models, Theoretical ; Oceans and Seas ; Particulate Matter/analysis ; Seawater/chemistry ; Water Movements ; Wind
    Chemical Substances Particulate Matter
    Language English
    Publishing date 2018-02-07
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S. ; Review
    ZDB-ID 2458404-6
    ISSN 1941-0611 ; 1941-1405
    ISSN (online) 1941-0611
    ISSN 1941-1405
    DOI 10.1146/annurev-marine-121916-063351
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: The Bottom Boundary Layer

    Trowbridge, John H. / Lentz, Steven J.

    2018  

    Abstract: The oceanic bottom boundary layer extracts energy and momentum from the overlying flow, mediates the fate of near-bottom substances, and generates bedforms that retard the flow and affect benthic processes. The bottom boundary layer is forced by winds, ... ...

    Abstract The oceanic bottom boundary layer extracts energy and momentum from the overlying flow, mediates the fate of near-bottom substances, and generates bedforms that retard the flow and affect benthic processes. The bottom boundary layer is forced by winds, waves, tides, and buoyancy and is influenced by surface waves, internal waves, and stratification by heat, salt, and suspended sediments. This review focuses on the coastal ocean. The main points are that (a) classical turbulence concepts and modern turbulence parameterizations provide accurate representations of the structure and turbulent fluxes under conditions in which the underlying assumptions hold, (b) modern sensors and analyses enable high-quality direct or near-direct measurements of the turbulent fluxes and dissipation rates, and (c) the remaining challenges include the interaction of waves and currents with the erodible seabed, the impact of layer-scale two- and three-dimensional instabilities, and the role of the bottom boundary layer in shelf-slope exchange.
    Subject code 551
    Language English
    Publisher Annual Reviews
    Publishing country de
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article: Direct Measurements of Mean Reynolds Stress and Ripple Roughness in the Presence of Energetic Forcing by Surface Waves

    Scully, Malcolm E. / Trowbridge, John H. / Sherwood, Christopher R. / Jones, Katie R. / Traykovski, Peter

    Journal of geophysical research. 2018 Apr., v. 123, no. 4

    2018  

    Abstract: Direct covariance observations of the mean flow Reynolds stress and sonar images of the seafloor collected on a wave‐exposed inner continental shelf demonstrate that the drag exerted by the seabed on the overlying flow is consistent with boundary layer ... ...

    Abstract Direct covariance observations of the mean flow Reynolds stress and sonar images of the seafloor collected on a wave‐exposed inner continental shelf demonstrate that the drag exerted by the seabed on the overlying flow is consistent with boundary layer models for wave‐current interaction, provided that the orientation and anisotropy of the bed roughness are appropriately quantified. Large spatial and temporal variations in drag result from nonequilibrium ripple dynamics, ripple anisotropy, and the orientation of the ripples relative to the current. At a location in coarse sand characterized by large two‐dimensional orbital ripples, the observed drag shows a strong dependence on the relative orientation of the mean current to the ripple crests. At a contrasting location in fine sand, where more isotropic sub‐orbital ripples are observed, the sensitivity of the current to the orientation of the ripples is reduced. Further, at the coarse site under conditions when the currents are parallel to the ripple crests and the wave orbital diameter is smaller than the wavelength of the relic orbital ripples, the flow becomes hydraulically smooth. This transition is not observed at the fine site, where the observed wave orbital diameter is always greater than the wavelength of the observed sub‐orbital ripples. Paradoxically, the dominant along‐shelf flows often experience lower drag at the coarse site than at the fine site, despite the larger ripples, highlighting the complex dynamics controlling drag in wave‐exposed environments with heterogeneous roughness.
    Keywords anisotropy ; continental shelf ; covariance ; fluid mechanics ; geophysics ; isotropy ; research ; roughness ; sand ; sonar ; wavelengths
    Language English
    Dates of publication 2018-04
    Size p. 2494-2512.
    Publishing place John Wiley & Sons, Ltd
    Document type Article
    Note JOURNAL ARTICLE
    ZDB-ID 161667-5
    ISSN 2169-9291 ; 2169-9275 ; 0148-0227 ; 0196-2256
    ISSN (online) 2169-9291
    ISSN 2169-9275 ; 0148-0227 ; 0196-2256
    DOI 10.1002/2017JC013252
    Database NAL-Catalogue (AGRICOLA)

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    In stock of ZB MED Bonn / Germany

    Z 2004/712: Show issues
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  4. Article: Optics, Acoustics and Stress in Situ (OASIS)

    Trowbridge, John H / Traykovski, Peter

    Abstract: To quantify and understand the effects of aggregation dynamics on the distribution of particles in the bottom boundary layer, and to understand how the properties of particles (composition, shape, and internal structure) affect their optical and ... ...

    Abstract To quantify and understand the effects of aggregation dynamics on the distribution of particles in the bottom boundary layer, and to understand how the properties of particles (composition, shape, and internal structure) affect their optical and acoustical properties. Obtain direct measurements of the turbulent Reynolds stress within the centimeters-thick wave boundary layer (WBL). Obtain concurrent velocity, turbulence and seafloor microtopography (bedforms) measurements to constrain the fluid dynamical environment within which the particle size distribution evolves. Improve state-of-the-technology for measuring boundary layer velocity and turbulence profiles (Pulse Coherent Doppler Profiler) and seafloor bedform measurements (Rotary Sidescan and Pencil-beam sonars).
    Language English
    Document type Article
    Database AGRIS - International Information System for the Agricultural Sciences and Technology

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  5. Article: CROSSTEX - Wave Breaking, Boundary Layer Processes, the Resulting Sediment Transport and Beach Profile Evolution

    Hsu, Tian-Jian / Trowbridge, John H.

    Abstract: Performed in cooperation with the Univeristy of Florida, Gainesville, FL. ...

    Abstract Performed in cooperation with the Univeristy of Florida, Gainesville, FL.
    Language English
    Document type Article
    Database AGRIS - International Information System for the Agricultural Sciences and Technology

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  6. Article: Analysis of Near-Surface Oceanic Measurements Obtained During CBLAST-Low

    Plueddemann, Albert J. / Trowbridge, John H.

    Abstract: Measurements obtained during the low-wind component of the Coupled Boundary Layers and Air-Sea Transfer program (CBLAST-Low) were used to elucidate the energetics of the ocean surface boundary layer. This work addressed the closure of the turbulent ... ...

    Abstract Measurements obtained during the low-wind component of the Coupled Boundary Layers and Air-Sea Transfer program (CBLAST-Low) were used to elucidate the energetics of the ocean surface boundary layer. This work addressed the closure of the turbulent kinetic energy (TKE) budget, the relationship between TKE and dissipation, and the roles of wave breaking and Langmuir circulation in controlling turbulent diffusivity. The measurements occurred primarily during conditions in which shear, buoyancy and wave breaking were important energy sources while Langmuir circulation was present but not dominant. The primary results were (l) The observed dissipation rate of TKE was enhanced relative that expected near a rigid boundary, and in good agreement with a scaling which assumes that TKE is extracted from the surface waves via breaking and dissipates as it is transported downward, (2) The dissipation rate of TKE was not balanced by local production or growth, indicating that the divergence of the flux of TKE was important, (3) The vertical distribution of TKE was reasonably well explained by a one-dimensional model incorporating the effects of surface gravity waves and shear instabilities, (4) Langmuir circulation did not appear to play a distinct role in boundary layer energetics.
    Language English
    Document type Article
    Database AGRIS - International Information System for the Agricultural Sciences and Technology

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  7. Article: Turbulence in the coastal environment during HYCODE

    Fredericks, Janet J. / Trowbridge, John H.

    Abstract: Funding was provided by the Office of Naval Research under Contract No. N00014-99-1-0213. ...

    Abstract Funding was provided by the Office of Naval Research under Contract No. N00014-99-1-0213.
    Language en_us
    Document type Article
    Database AGRIS - International Information System for the Agricultural Sciences and Technology

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  8. Article: Observations of near-bottom flow in a wave-dominated nearshore environment

    Fredericks, Janet J. / Trowbridge, John H. / Agrawal, Yogesh C.

    Abstract: Funding was provided by the Coastal Sciences Program of the Office of Naval Researchunder Grant N00014-92-J-12300. ...

    Abstract Funding was provided by the Coastal Sciences Program of the Office of Naval Researchunder Grant N00014-92-J-12300.
    Language en_us
    Document type Article
    Database AGRIS - International Information System for the Agricultural Sciences and Technology

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  9. Article: Turbulence in the shallow nearshore environment during SANDYDUCK '97

    Fredericks, Janet J. / Trowbridge, John H. / Voulgaris, George

    Abstract: An array of five acoustic Doppler velocimeters(ADV), which produce high quality measurements of the three-dimensional velocity vector in a sample volume with a scale of one centimeter, was deployed from late August through late November of 1997 at a ... ...

    Abstract An array of five acoustic Doppler velocimeters(ADV), which produce high quality measurements of the three-dimensional velocity vector in a sample volume with a scale of one centimeter, was deployed from late August through late November of 1997 at a water depth of approximately 4.5 m off Duck, North Carolina. The sensors were deployed near the sea floor but above the centimeters-thick wave boundary layer, and the sampling scheme was designed to resolve turbulence statistics averaged over tens of minutes, much longer than typical wave periods but shorter than time scales associated with variablity of energetic wind-driven and wave-driven alongshore flows.
    Language en_us
    Document type Article
    Database AGRIS - International Information System for the Agricultural Sciences and Technology

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  10. Article: Spatial variability of bottom turbulence over a linear sand ridge mooring deployment and AUTOSUB AUV survey cruise report R/V RRS Challenger, cruise number 146 Broken Bank, North Sea, U.K., 17 – 28 August 1999 cruise report

    Voulgaris, George / Trowbridge, John H. / Terray, Eugene A.

    Abstract: Funding was provided by the Office of Naval Research under Contract No. N00014-01-10255 and the Natural Environment Research Council, UK Award GST/02/2155 to the University of Southampton. ...

    Abstract Funding was provided by the Office of Naval Research under Contract No. N00014-01-10255 and the Natural Environment Research Council, UK Award GST/02/2155 to the University of Southampton.
    Language en_us
    Document type Article
    Database AGRIS - International Information System for the Agricultural Sciences and Technology

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