1,794 research outputs found
Large eddy simulation using unstructured spectral/h-p finite elements
No full textAvailable from British Library Document Supply Centre-DSC:DXN050537 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo
Building a training image with digital outcrop models
No full textCurrent standard geostatistical approaches to characterizing subsurface heterogeneity may not capture realistic facies geometries and fluid flow paths. Multiple-point statistics (MPS) has shown promise in portraying complex geometries realistically; however, realizations are limited by the reliability of the model of heterogeneity upon which MPS relies, that is the Training Image (TI). Attempting to increase realism captured in TIs, a quantitative outcrop analog based approach utilizing terrestrial lidar and high-resolution, calibrated digital photography is combined with lithofacies analysis to produce TIs.
Terrestrial lidar scans and high-resolution digital imagery were acquired of a Westwater Canyon Member, Morrison Formation outcrop in Ojito Wilderness, New Mexico, USA. The resulting point cloud was used to develop a cm scale mesh. Digital images of the outcrop were processed through a combination of photogrammetric techniques and manual digitizing to delineate different facies and sedimentary structures. The classified images were projected onto the high-resolution mesh creating a physically plausible Digital Outcrop Model (DOM), portions of which were used to build MPS TIs. The resulting MPS realization appears to capture realistic geometries of the deposit and empirically honors facies distributions
Steinaker Dam Construction
No full textView of Steinaker (Stanaker) Dam from U.S.C. and G.S. "Stanaker" located above the right abutment. Embankment portion of dam is near completion and the riprap is about 65% complete. Construction work is being performed by Morrison-Knudsen Company, Inc. under specifications DC-5160
Numerical simulation of free surface flows with steep gradients
No full textCivil Engineering and Geoscience
Finite element modelling of transport and non-hydrostatic flow in environmental fluid mechanics
No full textSectie VloeistofmechanicaCivil Engineering and Geoscience
Evolution of the floc size distribution of cohesive sediments
No full textThis thesis focuses on the flocculation process of cohesive sediment (mud) and in particular on the time evolution of the floc size distribution. Mud is mainly observed in estuarine environment and its settling velocity is strongly affected by its floc size distribution. Small flocs (1-50 micrometers) have a very small settling velocity and tend to remain in suspension while large flocs (50 micrometers-centimeters) are characterized by a large settling velocity and deposit rapidly inducing bed siltation. Moreover, small suspended flocs reduce light transmission through the water column and may carry pollutants through large distances. The investigation of the evolution of the floc size distribution is therefore relevant in the fields of civil engineering and ecology. Flocculation is the combination of the processes of aggregation and breakup and is influenced by the sediment and water properties, sediment concentration and turbulent motion. The relation between small scale particle-particles interactions and large-scale flocculation behavior is investigated in this thesis through both experimental and modeling work. In particular a series of coupled experiments where both the surface charge of the particles, quantified by their zeta-potential, and the flocculation behavior are observed. Flocculation is then modeled by means of a population balance equation where flocs are distributed in size classes and aggregation and breakup represent respectively birth and death of flocs in each class.Environmental fluid mechanicsCivil Engineering and Geoscience
Hydrodynamic models in urban drainage application and calibration
No full textCivil Engineering and Geoscience
Deterministic and Stochastic Modelling of Ocean Surface Waves
No full textPredicting the mean wave statistics in the nearshore, for instance the significant wave height, has predominantly been the domain of operational stochastic wave models based on the radiative transport (or energy balance) equation. Although reasonably successful in the nearshore, these models were originally developed for oceanic scales, and necessarily neglect or parametrise processes that are only significant in shallow water, such as the linear processes of interference and diffraction, or the nonlinear triad wave-wave interactions and dissipation due to wave breaking. In this dissertation we investigate the possibility of predicting the wave statistics on small scales in strongly non-linear conditions, such as found in the surfzone, using the recently developed Surface WAves till SHore (SWASH) model, whereas on larger scales we pursue a generalisation of existing stochastic models by incorporating coherent effects, hereby extending these models to include interference and diffractive effects.Hydraulic EngineeringCivil Engineering and Geoscience
Particle models for transport in three-dimensional shallow water flow
No full textCivil Engineering and Geoscience
Harnessing high altitude solar power
Get PDFAs an intermediate solution between Glaser's satellite solar power (SSP) and ground-based photovoltaic (PV) panels, this paper examines the collection of solar energy using a high-altitude aerostatic platform. A procedure to calculate the irradiance in the medium/high troposphere, based on experimental data, is described. The results show that here a PV system could collect about four to six times the energy collected by a typical U.K.-based ground installation, and between one-third and half of the total energy the same system would collect if supported by a geostationary satellite (SSP). The concept of the aerostat for solar power generation is then briefly described together with the equations that link its main engineering parameters/variables. A preliminary sizing of a facility stationed at 6 km altitude and its costing, based on realistic values of the input engineering parameters, is then presented
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