Laboratory investigation of pressure gradients induced by plunging breakers

Acuña, Adrián Pedrozo; Alegría-Arzaburu, Amaia Ruíz de; Torres-Freyermuth, Alec; Mendoza, Edgar; Silva, Rodolfo

doi:10.1016/j.coastaleng.2011.03.013

Cited by 31 publications

(16 citation statements)

References 32 publications

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“…V L was calculated with the influent flow and the cross-section reactor surface; V G was measured by bubble image velocimetry (BIV) technique, which allows the measurements of flow velocities in the aerated zone [33].…”

Section: Operating Conditions and Statistical Analysismentioning

confidence: 99%

Intermittent filtration and gas bubbling for fouling reduction in anaerobic membrane bioreactors

Cerón-Vivas

Morgan-Sagastume

Noyola

2012

Journal of Membrane Science

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Section: Operating Conditions and Statistical Analysismentioning

confidence: 99%

Intermittent filtration and gas bubbling for fouling reduction in anaerobic membrane bioreactors

Cerón-Vivas

Morgan-Sagastume

Noyola

2012

Journal of Membrane Science

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“…The local acceleration term is often considered as a proxy for pressure gradients [Drake and Calantoni, 2001]. However, observations [e.g., Baldock and Hughes, 2006;Pedrozo-Acuna et al, 2011] and numerical studies [e.g., Puleo et al, 2007;Pedrozo-Acuna et al, 2010] have suggested poor correlation between local acceleration and pressure gradients inside the swash and surf zones. We extend the previous work by Puleo et al [2007] in order to investigate the role of all terms in the along-slope momentum RANS equation given by,…”

Section: Momentum Balance In the Swash Zonementioning

confidence: 99%

Modeling swash‐zone hydrodynamics and shear stresses on planar slopes using Reynolds‐Averaged Navier–Stokes equations

2013

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.[1] A numerical model solving the Reynolds-Averaged Navier-Stokes equations, with a volume of fluid-tracking scheme and turbulence closure, is employed for estimating hydrodynamics in the swash zone. Model results for run-up distance, water depth, and near-bed velocity are highly correlated (r 2 > 0.97) with ensemble-averaged dam-break-driven swash data. Moreover, modeled bed shear stresses are within 20% of estimates derived from measured velocity profiles. Dam-break-driven swash simulations are conducted to determine the effect of foreshore characteristics (bed roughness and foreshore slope) on bore-induced swash-zone hydrodynamics and bed shear stresses. Numerical results revealed that the boundary layer vanishes during flow reversal, grows during the backwash, and becomes depth limited at the end of the swash cycle. In general, the uprush experiences larger shear stresses but for a shorter duration than the backwash. Some variability in this pattern is observed depending on the bed roughness, foreshore slope, and cross-slope location in the swash zone, implying that large spatial gradients in shear stresses can occur on the foreshore. The mean tangential force per unit area supplied to the bed is offshore directed for the simulated cases, with the exception of the mild-slope (1:25) cases, owing to the skewed nature of swash flows. The temporal evolution of the momentum balance inside the swash zone shows an important contribution to the total force from turbulence and advection at the early/final stage of the swash cycle, whereas the local acceleration does not appear to be a significant contribution.Citation: Torres-Freyermuth, A., J. A. Puleo, and D. Pokrajac (2013), Modeling swash-zone hydrodynamics and shear stresses on planar slopes using Reynolds-Averaged Navier-Stokes equations,

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“…Instrumentation 3.2.1. Pore-Pressure Transducer Array (PPTA) Laboratory observations of pore pressures and pressure gradients are traditionally collected using differential pressure sensors with piezometer tubes [Madsen, 1978;Baldock and Holmes, 1996;Sumer et al, 2011;Berni et al, 2017] or miniature strain gauge transducers or piezo-resistive transmitters [Suzuki et al, 2010;Pedrozo-Acuña et al, 2011]. Pressure gradient time series at a single location can be approximated using finite differences from multiple sensors in close proximity [Suzuki et al, 2010].…”

Section: Methodsmentioning

confidence: 99%

Observations of wave‐induced pore pressure gradients and bed level response on a surf zone sandbar

et al. 2017

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Horizontal and vertical pressure gradients may be important physical mechanisms contributing to onshore sediment transport beneath steep, near‐breaking waves in the surf zone. A barred beach was constructed in a large‐scale laboratory wave flume with a fixed profile containing a mobile sediment layer on the crest of the sandbar. Horizontal and vertical pore pressure gradients were obtained by finite differences of measurements from an array of pressure transducers buried within the upper several centimeters of the bed. Colocated observations of erosion depth were made during asymmetric wave trials with wave heights between 0.10 and 0.98 m, consistently resulting in onshore sheet flow sediment transport. The pore pressure gradient vector within the bed exhibited temporal rotations during each wave cycle, directed predominantly upward under the trough and then rapidly rotating onshore and downward as the wavefront passed. The magnitude of the pore pressure gradient during each phase of rotation was correlated with local wave steepness and relative depth. Momentary bed failures as deep as 20 grain diameters were coincident with sharp increases in the onshore‐directed pore pressure gradients, but occurred at horizontal pressure gradients less than theoretical critical values for initiation of the motion for compact beds. An expression combining the effects of both horizontal and vertical pore pressure gradients with bed shear stress and soil stability is used to determine that failure of the bed is initiated at nonnegligible values of both forces.

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Laboratory investigation of pressure gradients induced by plunging breakers

Cited by 31 publications

References 32 publications

Intermittent filtration and gas bubbling for fouling reduction in anaerobic membrane bioreactors

Intermittent filtration and gas bubbling for fouling reduction in anaerobic membrane bioreactors

Modeling swash‐zone hydrodynamics and shear stresses on planar slopes using Reynolds‐Averaged Navier–Stokes equations

Observations of wave‐induced pore pressure gradients and bed level response on a surf zone sandbar

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