Sam T. FredrikssonUniversity of Gothenburg | GU · Department of Marine Sciences
Sam T. Fredriksson
PhD
About
14
Publications
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170
Citations
Citations since 2017
Introduction
Additional affiliations
October 2016 - October 2018
Publications
Publications (14)
The report treats different types of climate information available for work on climate change adaptation. This includes both historical climate information and information based on future climate change projections. It also gives an update on the scientific knowledge related to climate change and presents new results for future conditions in Sweden...
Providing remote and off-grid coastal communities with renewable and sustainable electricity is a goal that could be met with tidal-stream technology. Presently there are many turbine designs, which presents a challenge when making an unbiased resource assessment. Moreover, the majority of tidal-stream turbines appear to be aimed at producing large...
The Deep Green technique for tidal power generation is suitable for moderate flows which is attractive since larger areas for tidal energy generation hereby can be used. It operates typically at mid-depth and can be seen as a “flying” kite with a turbine and generator attached underneath. It moves in a lying figure-eight path almost perpendicular t...
Tidal-stream energy can be predicted deterministically, provided tidal harmonics and turbine-device characteristics are known. Many turbine designs exist, all having different characteristics (e.g. rated speed), which creates uncertainty in resource assessment or renewable energy system-design decision-making. A standardised normalised tidal-stream...
Chemical cues and signals mediate resource acquisition, mate finding, and the assessment of predation risk in marine plankton. Here, we use the chemical properties of the first identified chemical cues from zooplankton together with in situ measurements of turbulent dissipation rates to calculate the effect of turbulence on the distribution of cues...
Tidal energy has the potential to provide a substantial part of the sustainable electric power generation. The tidal power plant developed by Minesto, called Deep Green, is a novel technology using a 'flying' kite with an attached turbine, moving at a speed several times higher than the mean flow. Multiple Deep Green power plants will eventually fo...
Air-water gas-exchange is studied in direct numerical simulations (DNS) of free-surface flows driven by natural convection and weak winds. The wind is modeled as a constant surface-shear-stress and the gas-transfer is modeled via a passive scalar. The simulations are characterized via a Richardson number where B, v, and u* are the buoyancy flux, ki...
The gas flux at the water surface is affected by physical processes including turbulence from wind shear, microscale wave breaking, large-scale breaking, and convection due to heat loss at the surface. The main route in the parameterizations of the gas flux has been to use the wind speed as a proxy for the gas flux velocity, indirectly taking into...
Direct numerical simulations (DNS) of free surface flows driven by natural convection are used to evaluate different methods of estimating air-water gas exchange at no-wind conditions. These methods estimate the transfer velocity as a function of either the horizontal flow divergence at the surface, the turbulent kinetic energy dissipation beneath...
The Eurofleets-2 PREPARED cruise was conducted during June 5–15, 2014 on board the Norwegian R/V G.O. Sars to investigate the present and past oceanographic flow regime and patterns around two contourite drifts located in the eastern side of the Fram Strait (south-western margin of Spitsbergen). To achieve the main objective of the project, we plan...
The dynamics of individual flexible fibers in a turbulent flow field have been analyzed, varying their initial position, density and length. A particle-level fiber model has been integrated into a general-purpose, open source computational fluid dynamics code. The fibers are modeled as chains of cylindrical segments connected by ball and socket joi...
The transport of gasses dissolved in surface waters across the water-atmosphere interface is controlled by the piston velocity (k). This coefficient has large implications for, e.g., greenhouse gas fluxes but is challenging to quantify in situ. At present, empirical k-wind speed relationships from a small number of studies and systems are often ext...
The effects of surfactants on the turbulent flow of a liquid cooled from above and driven by buoyant convection, are explored using direct numerical simulations. The limiting case of zero surface stress and an insoluble surfactant is investigated. It is found that relatively small amounts of surfactant can have a significant effect on the flow, and...
The dynamics of individual flexible fibers in a turbulent flow field have been studied. A particle-level fiber model has been integrated into a general purpose, open source Computational Fluid Dynamics (CFD) code. The fibers are modeled as chains of cylindrical segments connected by ball and socket joints. The fiber equations of motion contain the...
Projects
Project (1)
Present project using pseudo-spectral code NCAR-LES for full tidal cycle analysis of natural turbulence and finite volume code OpenFOAM in conjunction with a modified actuator line method to model the tidal power plant Deep Green. Deep green uses a novel technology using a kite-like wing with a turbine attached that sweeps the tidal flow with a velocity several times the mean flow.
