A5068601442- Coastal and Marine Dynamics
- Wave and Wind Energy Systems
- Fluid Dynamics and Vibration Analysis
- Fluid Dynamics Simulations and Interactions
- Hydrology and Sediment Transport Processes
- Microplastics and Plastic Pollution
- Fluid Dynamics and Turbulent Flows
- Hydraulic flow and structures
- Tropical and Extratropical Cyclones Research
- Offshore Engineering and Technologies
- Coastal wetland ecosystem dynamics
- Aeolian processes and effects
- Geological formations and processes
- Fish Ecology and Management Studies
- Ocean Waves and Remote Sensing
- Wind Energy Research and Development
- Recycling and Waste Management Techniques
- Geotechnical Engineering and Soil Stabilization
- Soil erosion and sediment transport
- Marine and fisheries research
- Energy Load and Power Forecasting
- Geotechnical Engineering and Underground Structures
- Cyclone Separators and Fluid Dynamics
- Marine and Offshore Engineering Studies
- Geotechnical Engineering and Soil Mechanics
Technical University of Denmark
2010-2024
California Maritime Academy
2006-2019
DHI
2009-2012
Danish Hydraulic Institute (India)
2011
The settling velocities of 66 microplastic particle groups, having both regular (58) and irregular (eight) shapes, are measured experimentally. Regular shapes considered include: spheres, cylinders, disks, square plates, cubes, other cuboids (square rectangular prisms), tetrahedrons, fibers. experiments generally consider Reynolds numbers greater than 102, extending the predominant range covered by previous studies. present data is combined with an extensive set from literature,...
This study continues the investigation of wave boundary layers reported by Carstensen, Sumer & Fredsøe ( J. Fluid Mech ., 2010, part 1 this paper). The present paper summarizes results an experimental turbulent solitary layers, simulated motion in oscillating water tunnel. Two kinds measurements were made: bed shear stress and velocity measurements. experiments show that solitary-motion layer experiences three flow regimes as Reynolds number is increased: (i) laminar regime; (ii) regime...
This paper presents experimental measurements of beaching times for buoyant microplastic particles released, both in the pre-breaking region and within surf zone. The are used to quantify cross-shore Lagrangian transport velocities microplastics. Prior breaking travel onshore with a velocity close fluid particle velocity, regardless characteristics. In zone microplastics increase become closer wave celerity. Furthermore, it is demonstrated that having low Dean numbers (dimensionless fall...
This work concerns oscillatory boundary layers over smooth beds. It comprises combined visual and quantitative techniques including bed shear stress measurements. The experiments were carried out in an oscillating water tunnel. reveal two significant coherent flow structures: (i) Vortex tubes, essentially two-dimensional vortices close to the extending across width of boundary-layer flow, caused by inflectional-point layer instability. imprint these is a series small, insignificant kinks...
This paper presents experimental results on the cross-shore distribution of non-buoyant microplastic particles under irregular waves propagating, shoaling and breaking live sediment sloping beds. Eighteen particle groups having various shapes, densities, sizes are tested. The experiments consider two initial bottom configurations corresponding to a (i) plane bed (ii) pre-developed singly-barred profile (more representative field conditions). Four different accumulation hotspots identified:...
The first 5MW baseline design of the DeepWind concept is presented for a Darrieus type floating wind turbine system water depths more than 150 m. This will be used as reference to test next technological improvements sub-component level, being based much possible on existing technology. iterative process involves all sub-components and potential constraints, most important dependencies are highlighted selected presented. blades designed with constraints minimize gravitational loads produced...
Loads from extreme waves can be dimensioning for the substructures of offshore wind turbines. The DeRisk project (2015-2019) aims at an improved load evaluation procedure through application advanced wave models, laboratory tests effects, development hydrodynamic aero-elastic response calculations and statistical analysis. This first paper outlines content philosophy behind DeRisk. Next, results with irregular are presented, including 2D 3D focused groups. group a 6-hour (full scale...
Incipient motion conditions for 57 regular (spheres, cylinders, disks, square plates, cubes, prisms, rectangular tetrahedrons, and fibers) eight irregular microplastic particle groups, having various sizes densities, are investigated in a circular flume. The present data set is combined with additional from the literature systematically analyzed. A new framework developed predicting incipient foreign particles, accounting variations static friction, hydraulic roughness, hiding-exposure...
Experimental results involving shoreface nourishment scenarios are presented. The experiments performed at small scale and the effects of placement timing in relation to long-term cross-shore profile development investigated. Four different tested experimentally, with positioned both trough a pre-developed as well along bar profile. demonstrate that under all erosion shoreline slows relative case without nourishment. two cases where was placed reduced more compared onshore bar. Compared past...
This study is a continuation of the investigation turbulent spots in wave boundary layers over smooth wall reported by Carstensen et al. [J. Fluid Mech. 646, 169–206 (2010)10.1017/S0022112009992825]. The present paper summarises results an experimental rough wall. Two kinds experiments were made: flow visualization tests and velocity profile measurements. show that as observed smooth-wall are irrespective roughness conditions. As case appear locally time space grow size progresses.
This study demonstrates how hydrodynamics can be used to influence the fishing performance of towed demersal gears. Sea trials are performed in sea star fishery show modifications gear design alter turbulent wake and consequently affect catching trawl The on cockle mussel beds effect gap between towing beam seabed, size investigated. Two different sizes utilized where a large reduces bycatch increases catch rate if positioned suitable distance over seabed. is independent line within...
The present study provides indications and underlying drivers of wave-induced transport retention potential microplastic particles (MP) in marine vegetation canopies having different densities. anthropogenic occurrence MP coastal waters is well documented the recent literature. It acknowledged that can serve as a sink for due to its energy dissipating features, which mimic novel ecosystem service. While behavior has previously been investigated some extent stationary flow conditions,...
This paper deals with the design of a 5MW floating offshore Vertical Axis Wind Turbine (VAWT). The is based on new wind turbine concept (DeepWind concept), consisting Darrieus rotor mounted spar buoy support structure, which anchored to sea bed mooring lines [1]. carried out in an iterative process, involving different sub-components and addressing several conflicting constraints. present does not aim be final optimum solution for this concept. Instead, goal have baseline model, technology,...
This paper presents the results of an experimental and numerical investigation mixing stratified flow around bridge pier structures. In this study, which was carried out in connection with Fehmarnbelt Fixed Link environmental impact assessment, processes two-layer stratification studied lower level had a higher salinity than upper layer. The physical experiments investigated two different designs. A general study made regarding forces on piers effect current angle relative to structure also...
An experimental and numerical study is carried out to investigate the flow up- downstream of a disc-attached cylinder near wall with Reynolds number Re=U0d/ν=5.4⋅104 (U0 mean upstream velocity, d diameter cylinder, ν kinematic viscosity). Laser Doppler Velocimetry measurements were conducted obtain statistical parameters such as velocity turbulent kinetic energy. The results show that can be characterized two-dimensional at transverse distance more than away from disc. Furthermore, it shown...