Searched for: subject%3A%22vortices%22
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Bauer, T.A. (author), Davis, Timothy J. (author), Frank, Bettina (author), Dreher, Pascal (author), Janoschka, David (author), Meiler, Tim C. (author), Meyer zu Heringdorf, Frank J. (author), Kuipers, L. (author), Giessen, Harald (author)
The creation and manipulation of optical vortices, both in free space and in two-dimensional systems such as surface plasmon polaritons (SPPs), has attracted widespread attention in nano-optics due to their robust topological structure. Coupled with strong spatial confinement in the case of SPPs, these plasmonic vortices and their underlying...
journal article 2023
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Pinto Ribeiro, A. (author), Muscari, C. (author)
Simulating entire wind farms with an actuator line model requires significant computational effort, especially if one is interested in wake dynamics and wants to resolve the tip vortices. A need to explore unconventional approaches for this kind of simulation emerges. In this work, the actuator line method is implemented within a lattice...
journal article 2023
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Molahalli, Pranav (author)
Due to the global energy crisis, there is a growing need to make industrial processes more efficient and clean. One such method is to use effective and renewable working fluids in power and refrigeration cycles. Research in this field during the past decade has placed supercritical CO2 (SCO2) in the forefront due to its non-ideal properties and...
master thesis 2022
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Pathanadka, Chinmaya (author)
Aerodynamics has played a significant role in the industry of motorsports in improving the performance and handling of the race car. Rob Smedley, the former head of vehicle performance at Williams Racing stated that - "Where teams have problems is when their development or simulation environment – so CFD [Computational Fluid Dynamics] or wind...
master thesis 2022
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van Meerkerk, M. (author), Poelma, C. (author), Hofland, Bas (author), Westerweel, J. (author)
We present an experimental study on the gas flow field development over a plunging breaking wave prior to impact on a vertical wall. The variability of wave impact pressure over repeated measurements is well known (Bagnold, 1939). The formation of instabilities on the wave crest are postulated to be the main source of impact pressure variability...
journal article 2022
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Hirschberg, L. (author), Bake, F. (author), Knobloch, K. (author), Hulshoff, S.J. (author), Hirschberg, A. (author)
An experimental cold-gas study of the response of a choked convergent–divergent nozzle to swirl perturbations is presented. The perturbations were obtained by means of upstream unsteady tangential injections into initially steady flows with different values of steady background swirl. The swirl perturbations induced changes in the axial mass...
journal article 2022
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Lima Pereira, L.T. (author), Ragni, D. (author), Avallone, F. (author), Scarano, F. (author)
The impact of aerodynamic loading on a serrated trailing edge is studied experimentally. Aerodynamic and acoustic measurements are conducted on a sawtooth-shaped trailing edge, retrofitted to a flat plate featuring a trailing-edge flap, and placed at incidence to the free-stream flow. The turbulent flow across the trailing edge is inspected...
journal article 2022
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van der Boog, C.G. (author), Molemaker, M. J. (author), Dijkstra, H. A. (author), Pietrzak, J.D. (author), Katsman, C.A. (author)
Mesoscale anticyclonic eddies dominate the sea-surface height variability in the Caribbean Sea. Although it is well established that these anticyclones are formed near the eastern boundary of the Caribbean Sea, which is demarcated by the Lesser Antilles, the source of their anticyclonic vorticity remains unclear. To gain insight into this...
journal article 2022
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Geyer, A. (author), Quirchmayr, Ronald (author)
We develop a Korteweg-De Vries (KdV) theory for weakly nonlinear waves in discontinuously stratified two-layer fluids with a generally prescribed rotational steady current. With the help of a classical asymptotic power series approach, these models are directly derived from the divergence-free incompressible Euler equations for unidirectional...
journal article 2022
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Marynets, K. (author)
We discuss a mathematical model for the equatorial current across the Pacific Ocean, obtained as a leading-order solution to the Navier-Stokes governing equations for geophysical flows in a rotating frame.
journal article 2020
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Bakker, Floor (author)
To exploit its socio-economic functions, engineering measures are regularly applied in estuaries. Estuaries are, however, known to be very complex systems. Stemming from this complexity is the generation of a so-called estuarine turbidity maximum (ETM), which poses great siltation problems to the engineering measures. An engineering measure,...
master thesis 2020
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RAMESH KUMAR, KISHAN (author)
Optical measurement techniques are widely used in fluid mechanics to measure quantities like velocity, vorticity, and temperature. They are usually non-intrusive visualization techniques that provide a major advantage by not influencing the flow properties. Most of the developed measurement techniques estimate vorticity by computing the...
master thesis 2019
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Baldacchino, D. (author)
Vortex generators have become a ubiquitous sight on the modern wind turbine blade. These small, passive devices can increase the energy extraction potential of a rotor, but their subtle footprint disguises the technical difficulties associated with designing and integrating them onto wind turbine blades. The complexity of rotor inflow and the...
doctoral thesis 2019
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de Angelis, L. (author)
In this thesis, we explore the physics of optical singularities. We investigate them in light waves propagating randomly in a planar nanophotonic chip. With a custom-built nearfield microscope, we map the electromagnetic field resulting from the interference of these light waves. Our technique gives access to the full vectorial and complex...
doctoral thesis 2018
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Liu, S. (author), Ye, Qinghua (author), Wu, Shiqiang (author), Stive, M.J.F. (author)
Wind induced hydrodynamic circulations play significant roles in the transport and mixing process of pollutants and nutrients in large shallow lakes, but they have been usually overlooked, while environmental, biological, and ecological aspects of eutrophication problems get the most focus. Herein we use a three-dimensional model, driven by...
journal article 2018
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Broekema, Y.B. (author), Labeur, R.J. (author), Uijttewaal, W.S.J. (author)
Scour in the vicinity of a hydraulic structure may compromise its geotechnical stability or that of nearby structures. Much fundamental research has been dedicated to the understanding and prediction of these processes, in order to enable the efficient design of mitigation measures. While most of these efforts consider laterally uniform flows,...
journal article 2018
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Waldman, Robin (author), Brüggemann, N. (author), Bosse, Anthony (author), Spall, Michael (author), Somot, Samuel (author), Sevault, Florence (author)
For more than five decades, the Mediterranean Sea has been identified as a region of so-called thermohaline circulation, namely, of basin-scale overturning driven by surface heat and freshwater exchanges. The commonly accepted view is that of an interaction of zonal and meridional conveyor belts that sink at intermediate or deep convection...
journal article 2018
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de Angelis, L. (author), Alpeggiani, F. (author), Di Falco, Andrea (author), Kuipers, L. (author)
Phase singularities are locations where light is twisted like a corkscrew, with positive or negative topological charge depending on the twisting direction. Among the multitude of singularities arising in random wave fields, some can be found at the same location, but only when they exhibit opposite topological charge, which results in their...
journal article 2017
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Yang, Y. (author), Veldhuis, L.L.M. (author), Eitelberg, G. (author)
Abstract: During the ground operation of aircraft, the interaction between the propulsor-induced flow field and the ground may lead to the generation of ground vortices. Utilizing numerical approaches, the source of vorticity entering ground vortices is investigated. The results show that the production of wall-parallel components of...
journal article 2017
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Yang, Y. (author), Sciacchitano, A. (author), Veldhuis, L.L.M. (author), Eitelberg, G. (author)
Abstract: The interaction between a propeller and its self-induced vortices originating on the ground is investigated in a scaled experiment. The velocity distribution in the flow field in two different planes containing the self-induced vortices is measured by particle image velocimetry (PIV). These planes are a wall–parallel plane in close...
journal article 2017
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