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Portland State University

Civil and Environmental Engineering Faculty Publications and Presentations

Plumes (Fluid dynamics)

Publication Year

Articles 1 - 5 of 5

Full-Text Articles in Engineering

River Influences On Shelf Ecosystems: Introduction And Synthesis, Barbara M. Hickey, Raphael M. Kudela, Jonathan Nash, Kenneth W. Bruland, William T. Peterson, P. Maccready, Evelyn J. Lessard, David A. Jay, Neil S. Banas, Antonio M. Baptista, Edward P. Dever, P. Michael Kosro, Levi Kilcher, Alexander R. Horner-Devine, Edward D. Zaron, Ryan M. Mccabe, Jay O. Peterson, Philip M. Orton, Jiayi Pan Feb 2010

River Influences On Shelf Ecosystems: Introduction And Synthesis, Barbara M. Hickey, Raphael M. Kudela, Jonathan Nash, Kenneth W. Bruland, William T. Peterson, P. Maccready, Evelyn J. Lessard, David A. Jay, Neil S. Banas, Antonio M. Baptista, Edward P. Dever, P. Michael Kosro, Levi Kilcher, Alexander R. Horner-Devine, Edward D. Zaron, Ryan M. Mccabe, Jay O. Peterson, Philip M. Orton, Jiayi Pan

Civil and Environmental Engineering Faculty Publications and Presentations

River Influences on Shelf Ecosystems (RISE) is the first comprehensive interdisciplinary study of the rates and dynamics governing the mixing of river and coastal waters in an eastern boundary current system, as well as the effects of the resultant plume on phytoplankton standing stocks, growth and grazing rates, and community structure. The RISE Special Volume presents results deduced from four field studies and two different numerical model applications, including an ecosystem model, on the buoyant plume originating from the Columbia River. This introductory paper provides background information on variability during RISE field efforts as well as a synthesis of results, …


Initial Expansion Of The Columbia River Tidal Plume: Theory And Remote Sensing Observations, David A. Jay, Edward D. Zaron, Jiayi Pan Jan 2010

Initial Expansion Of The Columbia River Tidal Plume: Theory And Remote Sensing Observations, David A. Jay, Edward D. Zaron, Jiayi Pan

Civil and Environmental Engineering Faculty Publications and Presentations

Analysis of the Columbia River tidal plume using Lagrangian frontal equations provides a concise description of the evolution of frontal depth H, velocity U, reduced gravity g', and frontal internal Froude number F (sub R) . Because the estuary mouth is narrow, the initial radial plume motion is supercritical (F (sub R) > 1) for up to 12 hours. Understanding this supercritical phase is vital, because plume properties change rapidly, with strong ecosystem impacts. To analyze this expansion, analytical and numerical models (the latter with three mixing formulations) were tested. Model results are compared to synthetic aperture radar images to verify …


Determining Azimuthal Variations In Frontal Froude Number From Sar Imagery, Jiayi Pan, David A. Jay, Hui Lin Aug 2009

Determining Azimuthal Variations In Frontal Froude Number From Sar Imagery, Jiayi Pan, David A. Jay, Hui Lin

Civil and Environmental Engineering Faculty Publications and Presentations

River plume fronts are the locus of strong mixing between plume and ambient coastal waters, contribute to coastal productivity, and exert a major impact on coastal ecosystems. The frontal Froude number Fr is an important parameter characterizing the frontal status with respect to both propagation and vertical mixing. In this study, we examine azimuthal variations in Fr using a new remote sensing method. We derive Fr from SAR image data on the basis of the SAR imaging theory and the mechanism of internal wave fission at front. This method is applied to a SAR image showing a front off the …


Effects Of Ambient Velocity Shear On Nonlinear Internal Wave Associated Mixing At The Columbia River Plume Front, Jiayi Pan, David A. Jay Jun 2008

Effects Of Ambient Velocity Shear On Nonlinear Internal Wave Associated Mixing At The Columbia River Plume Front, Jiayi Pan, David A. Jay

Civil and Environmental Engineering Faculty Publications and Presentations

Large-amplitude nonlinear internal waves (NLIWs) are frequently observed propagating away from Columbia River tidal plume fronts. They are generated because of the deceleration of the frontal bulge. During the River Influences on Shelf Ecosystems project cruises, the velocity, density structure and acoustic backscatter of the plume fronts and frontal NLIWs were observed using a towed vehicle, vessel-mounted instrumentation, and a vessel X band radar. These observations indicate that in the presence of strong ambient velocity shear, the NLIWs with maximum amplitudes occur well below the density interface and at a depth deeper than in the absence of shear. This deepening …


Analyses Of Internal Solitary Waves Generated At The Columbia River Plume Front Using Sar Imagery, Jiayi Pan, David A. Jay Jul 2007

Analyses Of Internal Solitary Waves Generated At The Columbia River Plume Front Using Sar Imagery, Jiayi Pan, David A. Jay

Civil and Environmental Engineering Faculty Publications and Presentations

Internal solitons generated at the Columbia River plume front during ebb tide are displayed on a synthetic aperture radar (SAR) image taken on 26 July 2004 at 14:24:22 UTC. Scale analyses suggest that these internal solitons belong to the finite-depth category. A theoretical model, relating the radar backscatter cross section to dynamic parameters of internal solitons in the continuous stratification, is developed. Using the model and background stratification data collected by the River Influences on Shelf Ecosystem (RISE) project in July 2004, we extract the soliton dynamic parameters of the half-width, amplitude, phase speed, and average energy flux per crest …