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Horsholm, Denmark

Larsen T.J.,Technical University of Denmark | Kallesoe B.S.,Technical University of Denmark | Hansen H.F.,Danish Hydraulic Institute
Proceedings of the International Offshore and Polar Engineering Conference | Year: 2011

In this paper we present a comparison between simulated and measured loads and dynamic motions for the floating wave energy platform Poseidon equipped with three wind turbines. In order to simulate the response of the system, the aeroelastic code HAWC2 which is state-of-the-art within wind turbine simulation has been extended to handle multiple rotors and is coupled to the time-domain diffraction/radiation solver for floating systems WAMSIM from the Danish Hydraulic Institute. Copyright © 2011 by the International Society of Offshore and Polar Engineers (ISOPE).

Cronin K.,Deltares | Cronin K.,University College Cork | Devoy R.J.D.,University College Cork | Montserrat F.,Danish Hydraulic Institute | Montserrat F.,Netherlands Institute of Ecology
Journal of Coastal Research | Year: 2011

On short timescales of days to weeks, sediment transport in coastal and estuarine environments may be investigated using a tracer technique. This paper describes a set of experiments using fluorescent tracer particles on the intertidal sand flats of the Argideen Estuary, south coast of Ireland, to examine the use of a fluorescent tracer to determine sediment transport patterns as part of a validation dataset for a morphological model. The spatial and temporal limits of this methodology were also assessed. Fluorescent tracer particles were mixed with sand taken from the site and moulded into 0.3 m by 0.3 m plates, deployed at different locations on the sand flats, at different times of the year. A lagrangian sampling approach was used to assess the direction and to estimate the magnitude of tracer transport. A series of short cores were taken over a gridded network of points around each plate, at different time intervals after each deployment. The number of tracer particles found in each core was semi-quantified. Several experiments were carried out throughout the estuary to test the method and it is shown that it was useful to both qualitatively and semi-quantitatively determine the dominant direction of sediment transport at each location. Tracer patterns are clear and consistent enough between the experiments to justify the determination of the sediment transport pathways and therefore provided a useful method of validating the sediment transport pathways simulated with the model.

Brankovic M.,JP Kenny Pty Ltd. | Zeitoun H.,JP Kenny Pty Ltd. | Sutherland J.,HR Wallingford | Pearce A.,Woodside Energy | And 5 more authors.
Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE | Year: 2010

One of the aspects of pipeline design is ensuring pipeline stability on the seabed under the action of environmental loads. During the 1980s, significant efforts were made to improve the understanding of hydrodynamic loads on single pipeline configurations on the seabed (Reference 1). The stability of piggyback (bundled) pipeline configurations is less well understood, with little quantitative data readily available to the design engineer for practical application in engineering problems (References 2-6). This paper describes an extensive set of physical model tests performed for piggyback on-seabed and piggyback-raised-from seabed (spanning or lifting pipeline) configurations to determine hydrodynamic forces in combined wave and current conditions. The piggyback is nominally in the 12 o'clock position. The well-established carriage technique was used, in order to obtain data for use in full-scale stability modelling. The model tests are benchmarked against existing test data, to confirm the validity of the test method. Key findings are presented in terms of non-dimensional coefficients, and force time histories for the vertical and horizontal forces. A brief interpretation of the hydrodynamic load behaviour of the Piggyback System is provided by considering the physical flow mechanisms causing the force time history variation; furthermore the influence of the seabed separation on the piggyback loads is also discussed. © 2010 by ASME.

Liu H.,Beijing Normal University | Ding Y.,Beijing Normal University | Li M.,Beijing Normal University | Lin P.,Danish Hydraulic Institute | And 2 more authors.
River Research and Applications | Year: 2015

In this study, a two-dimensional hybrid numerical model for sediment transport based on lattice Boltzmann method and finite difference method is presented. The governing equations for water flow and suspended sediment transport are the shallow water equations and the advection-diffusion equations, respectively. Sediment load is also involved, so that riverbed deformation is numerically simulated. The model is verified by testing transportation of bank-slump sediment in a sharp bended channel with the comparison to the results of well-accepted finite volume method, illustrating the effectiveness of the proposed hybrid model. © 2014 John Wiley & Sons, Ltd.

Lorke S.,RWTH Aachen | Bruning A.,RWTH Aachen | Van Der Meer J.,Van der Meer Consulting B.V. | Schuttrumpf H.,RWTH Aachen | And 7 more authors.
Proceedings of the Coastal Engineering Conference | Year: 2010

Intention of the project FlowDike-D is to quantify the impacts of current and wind on wave run-up and wave overtopping and to consider these processes in existing design formulae for estuarine, river and sea dikes. Physical model tests were carried out in the shallow water basin at DHI (Hørsholm/ Denmark) for two different dike geometries (1:3 and 1:6 sloped dike). The paper introduces the model setup and test programme followed by a short description of the applied instrumentation. The test results for wave run-up and wave overtopping with oblique and non-oblique wave attack, but without current, correspond well with existing formulae from the EurOtop-Manual (2007). The influence of current parallel to the dike combined with different angles of wave attack on wave overtopping and wave run-up has been quantified. A distinction was made between wave attack with and against the current.

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