Manometer tubes for coastal hydrodynamics investigations

Nielsen, Peter; Dunn, Scott

doi:10.1016/s0378-3839(98)00021-0

Cited by 12 publications

(7 citation statements)

References 3 publications

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“…The measurements also showed that that there was no amplification or damping in the response. (We note that Nielsen and Dunn [1998] give a detailed review of frequency response of piezometer tubes for coastal hydrodynamics applications. )…”

Section: Methodsmentioning

confidence: 99%

Flow and sediment transport induced by a plunging solitary wave

Sumer¹,

Sen²,

Karagali³

et al. 2011

J. Geophys. Res.

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[1] Two parallel experiments involving the evolution and runup of plunging solitary waves on a sloping bed were conducted: (1) a rigid-bed experiment, allowing direct (hot film) measurements of bed shear stresses and (2) a sediment-bed experiment, allowing for the measurement of pore water pressures and for observation of the morphological changes. The two experimental conditions were kept as similar as possible. The experiments showed that the complete sequence of the plunging solitary wave involves the following processes: shoaling and wave breaking; runup; rundown and hydraulic jump; and trailing wave. The bed shear stress measurements showed that the mean bed shear stress increases tremendously (with respect to that in the approaching wave boundary layer), by as much as a factor of 8, in the runup and rundown stages, and that the RMS value of the fluctuating component of the bed shear stress is also affected, by as much as a factor of 2, in the runup and hydraulic jump stages. The pore water pressure measurements showed that the sediment at (or near) the surface of the bed experiences upward directed pressure gradient forces during the down-rush phase. The magnitude of this force can reach values as much as approximately 30% of the submerged weight of the sediment. The experiments further showed that the sediment transport occurs in the sheet flow regime for a substantial portion of the beach covering the area where the entire sequence of the wave breaking takes place. The bed morphology is explained qualitatively in terms of the measured bed shear stress and the pressure gradient forces.

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Section: Methodsmentioning

confidence: 99%

Flow and sediment transport induced by a plunging solitary wave

Sumer¹,

Sen²,

Karagali³

et al. 2011

J. Geophys. Res.

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“…This section outlines the theoretical development of Nielsen et al (1993) (see also Nielsen and Dunn, 1998). A water wave-induced pressure wave inside the tube is reflected by the transducer at the landward end which sets up a "quarter length" resonating system.…”

Section: Theoretical Backgroundmentioning

confidence: 97%

Manometer tubes for monitoring coastal water levels: New frequency response factors

Jafari

Cartwright

Nielsen

2012

Coastal Engineering

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This paper presents findings of new laboratory experiments on the frequency response of semi-rigid manometer tubes for use in monitoring coastal hydrodynamic processes, extending and improving upon the previous work of Nielsen et al. (1993). An adjustable speed rotary electromotor was used to drive a known water level variation at one end of the tube and the pressure was measured at both ends of the tube, enabling a direct determination of the tube's frequency response. Testing was conducted over a range of frequencies (0.0067Hz< f <2Hz) and tube lengths (10m

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“…Previous studies have not taken into account the spatially variable flow field. Since it is extremely difficult to measure the flow in the aquifer directly, piezometers are often used to obtain data on the hydraulic head distribution from which the flow patterns are inferred (Nielsen and Dunn 1998). On the other hand, the Darcy's law and Ghyben-Herzberg relationships have been used to calculate the velocity approximately (McLachlan and Illenberger, 1986).…”

Section: Introductionmentioning

confidence: 99%

Submarine groundwater discharge (SGWD): an unseen yet potentially important coastal phenomenon in Canada

2011

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Both terrestrial and fresh or marine forces drive underground fluid flows in the coastal zone. Hydraulic gradients on land result in groundwater seepage near shore and may contribute to flows from confined aquifers further out on the shelf. The terrestrial and oceanic forces overlap spatially, so measured fluid advection through coastal sediments may be a result of composite forcing. ''Subsurface/submarine groundwater discharge'' (SGWD) can be defined as any and all flow of water on continental margins from the seabed to the coast, regardless of fluid composition or driving force. SGWD is typically characterized by low specific flow rates, making detection and quantification difficult. However, because such flows occur over very large areas, the total flux is significant. Discharging fluids, whether derived from land or composed of re-circulated seawater, will react with sediment components. These reactions may substantially increase the concentrations of nutrients, carbon, and metals in the fluids. These fluids are thus a source of biogeochemically important constituents to the coast. Terrestrially derived fluids represent a pathway for the flux of new material to the coast. This may result in diffuse pollution in areas where the discharge of contaminated groundwater occurs. This review presents an historical context of SGWD studies, defines the process in a form that is consistent with our current understanding of the driving forces as well as our assessment techniques, and reviews the estimated global fluxes and biogeochemical implications. This review concludes that, to fully characterize marine geochemical budgets, one must give due consideration to SGWD. New methodologies, technologies, and modeling approaches are required to discriminate among the various forces that drive SGWD, pollutants to evaluate these fluxes more precisely to Canadian coast.

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Manometer tubes for coastal hydrodynamics investigations

Cited by 12 publications

References 3 publications

Flow and sediment transport induced by a plunging solitary wave

Flow and sediment transport induced by a plunging solitary wave

Manometer tubes for monitoring coastal water levels: New frequency response factors

Submarine groundwater discharge (SGWD): an unseen yet potentially important coastal phenomenon in Canada

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