Implementing Effective Performance Turbine Model into TELEMAC-3D

Hydrodynamic

Flow around submerged groynes in a sharp bend using a 3D LES model

River hydrodynamicsInteraction with structure

Analysis of the riverbed backscattered signal registered by ADCPs in different bedload transport conditions – field application

Acoustic Doppler current profilers (ADCP) were deployed to investigate the backscattering (BS) signal in three navigable rivers, in different bedload transport conditions. This study aims to demonstrate that the BS strength, as an additional variable to the apparent bedload velocity, improves the characterization of the bedload transport using ADCPs. The M9 -3 MHz and the vertical beam M9 - 0.5 MHz showed decline of the BS strength as the bedload intensity increased, whereas the RDI -1.2 MHz was relatively insensitive. The correlation between the median grain size and the BS strength for the 0.5 MHz was linear, for the 3 MHz the BS strength was attenuated in the active layer, and for 1.2 MHz, it revealed a parabolic distribution. Moreover, the analyses of the ADCP measured variables, using wavelet transformations and unsupervised machine learning, highlighted the importance of the spatial and temporal variance and transient nature of the bedload transport

Hydraulic validation of two-dimensional simulations of braided river flow with spatially continuous aDcp data

Gravel‐bed braided rivers are characterized by shallow, branching flow across low relief, complex, and mobile bed topography. These conditions present a major challenge for the application of higher dimensional hydraulic models, the predictions of which are nevertheless vital to inform flood risk and ecosystem management. This paper demonstrates how high‐resolution topographic survey and hydraulic monitoring at a density commensurate with model discretization can be used to advance hydrodynamic simulations in braided rivers. Specifically, we detail applications of the shallow water model, Delft3d, to the Rees River, New Zealand, at two nested scales: a 300 m braid bar unit and a 2.5 km reach. In each case, terrestrial laser scanning was used to parameterize the topographic boundary condition at hitherto unprecedented resolution and accuracy. Dense observations of depth and velocity acquired from a mobile acoustic Doppler current profiler (aDcp), along with low‐altitude aerial photography, were then used to create a data‐rich framework for model calibration and testing at a range of discharges. Calibration focused on the estimation of spatially uniform roughness and horizontal eddy viscosity, νH, through comparison of predictions with distributed hydraulic data. Results revealed strong sensitivity to νH, which influenced cross‐channel velocity and localization of high shear zones. The high‐resolution bed topography partially accounts for form resistance, and the recovered roughness was found to scale by 1.2–1.4 D84 grain diameter. Model performance was good for a range of flows, with minimal bias and tight error distributions, suggesting that acceptable predictions can be achieved with spatially uniform roughness and νH.Field campaigns were primarily funded by NERC Grant NE/G005427/1 and NERC Geophysical Equipment Facility Loan 892 as well as NSERC and CFI (Canada) grants to Colin Rennie. Damia Vericat was supported by a Ramon y Cajal Fellowship (RYC‐2010‐06264) funded by the Spanish Ministry of Science and Innovation during the preparation of this manuscript. Numerical simulations were undertaken during a visit by Richard Williams to NIWA. This visit was funded by the British Hydrology Society and an Aberystwyth University Postgraduate Studentship. Murray Hicks and Richard Measures were funded by NIWA core funding under the Sustainable Water Allocation Programme

Evaluation of aDcp processing options for secondary flow identification at river junctions

Secondary circulation in river confluences results in a spatial and temporal variation of fluid motion and a relatively high level of morphodynamic change. Acoustic Doppler current profiler (aDcp) vessel-mounted flow measurements are now commonly used to quantify such circulation in shallow water fluvial environments. It is well established that such quantification using vessel-mounted aDcps requires repeated survey of the same cross-section. However, less attention has been given to how to process these data. Most aDcp data processing techniques make the assumption of homogeneity between the measured radial components of velocity. As acoustic beams diverge with distance from the aDcp probe, the volume of the flow that must be assumed to be homogeneous between the beams increases. In the presence of secondary circulation cells, and where there are strong rates of shear in the flow, the homogeneity assumption may not apply, especially deeper in the water column and close to the bed. To reduce dependence on this assumption, we apply a newly-established method to aDcp data obtained for two medium-sized (~60-80 m wide) gravel-bed river confluences and compare the results with those from more conventional data processing approaches. The comparsion confirms that in the presence of strong shear our method produces different results to more conventional approaches. In the absence of a third set of fully independent data, we cannot demonstrate conclusively which method is best, but our method involves less averaging and so in the presence of strong shear is likely to be more reliable. We conclude that it is wise to apply both our method and more conventional methods to identify where data analysis might be impacted upon by strong shear and where inferences of secondary circulation may need to be made more cautiously

In Vulcan's Forge

Investigations on the correlations between glass and magma involving members of staff from the Glass Department at the University of Sunderland and volcanologists, Dr Fabian Wadsworth and Dr Ed Llewellin from the Natural Sciences Department of Durham University. From a physico-chemical perspective, both magmas and the hot glass manipulated by glass artists are one and the same. The proposed the research question; ‘what lessons can geoscientists learn from knowledge-exchange and experimentation with glass artists?

ISSN exercise & sport nutrition review: research & recommendations

Sports nutrition is a constantly evolving field with hundreds of research papers published annually. For this reason, keeping up to date with the literature is often difficult. This paper is a five year update of the sports nutrition review article published as the lead paper to launch the JISSN in 2004 and presents a well-referenced overview of the current state of the science related to how to optimize training and athletic performance through nutrition. More specifically, this paper provides an overview of: 1.) The definitional category of ergogenic aids and dietary supplements; 2.) How dietary supplements are legally regulated; 3.) How to evaluate the scientific merit of nutritional supplements; 4.) General nutritional strategies to optimize performance and enhance recovery; and, 5.) An overview of our current understanding of the ergogenic value of nutrition and dietary supplementation in regards to weight gain, weight loss, and performance enhancement. Our hope is that ISSN members and individuals interested in sports nutrition find this review useful in their daily practice and consultation with their clients

Bed mobility of gravel rivers: mobilization (scour) depth of chum salmon redds, and equilibrium bedload transport

This thesis is an investigation of bed mobility in gravel-bed rivers. In particular, two hypotheses are addressed: 1) that mobilization (scour) depth in salmon egg nests (redds) differs from that of surrounding bed, and 2) that equilibrium bedload transport rate in gravel-bed rivers can be predicted by assuming equal mobility and accounting for armouring and particle hiding/exposure. To test the first hypothesis, a single spawning reach of Kanaka Creek, British Columbia was monitored for scour depth using a spatially intensive array of wiffle-ball monitors. Monitors were placed in and around egg pockets and tailspills of chum salmon (Oncorhynchus keta) redds. Scour and fill were recorded during each flood event of the 1997/98 flood season. Only one flood event was observed to cause widespread and deep scour and fill. Scour and fill were found to be highly spatially variable, and depended upon local factors such as bed structure, proximity to banks, and the influence of flow obstructions such as large woody debris. Despite the most spatially intensive monitoring to date, no spatial autocorrelation was observed in scour depths. By various nonparametric analyses of variance, mean scour depth of redd egg pockets was not found to differ significantly from that of surrounding bed, but the mean scour depth in tailspills of redds was significantly different from surrounding bed. However, small sample sizes limit the generality of the results. The second hypothesis was evaluated by development of a largely empirical model. Fractional bedload transport rates were estimated through modification of a bedload estimate for median size particles. Armouring was considered through modification of the fractional transport rate by the percent representation in the surface of the size fraction. The effects of relative differences in particle size, due to hiding/exposure interactions and different particle mass, were considered by means of a mobility factor (D/D50)\ Data from ten different studies, including 38 surface/subsurface size distributions and 17 equal transport mobility fractional bedload rate data sets, were utilized to develop the model. Equal transport mobility was assumed to evaluate the exponent x. The exponent x was found empirically to be a function of the surface sorting. The modified transport during a state of equal transport mobility was empirically found to be a function of the nondimensional bed shear stress. Finally, a simple model was proposed to estimate mean scour depth during high flow (equally mobile) events. The scour model combined the new bedload transport model with a fundamental bedload model. Somewhat surprisingly, due to uncertainty in estimates for scour model inputs, the scour model appeared to perform well when tested against the scour measurements.Applied Science, Faculty ofCivil Engineering, Department ofGraduat