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van Hout, R.L.H. (author), Eisma, H.E. (author), Elsinga, G.E. (author), Westerweel, J. (author)
In many applications, finite-sized particles are immersed in a turbulent boundary layer (TBL) and it is of interest to study wall effects on the instantaneous shedding of turbulence structures and associated mean velocity and Reynolds stress distributions. Here, 3D flow field dynamics in the wake of a prototypical, small sphere (D+=50, 692&lt...
journal article 2018
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van Emmerik, T.H.M. (author), Steele-Dunne, S.C. (author), Hut, R.W. (author), Gentine, Pierre (author), Guerin, Marceau (author), Oliveira, Rafael (author), Wagner, Jim (author), Selker, John (author), van de Giesen, N.C. (author)
Trees play a crucial role in the water, carbon and nitrogen cycle on local, regional and global scales. Understanding the exchange of momentum, heat, water, and CO 2 between trees and the atmosphere is important to assess the impact of drought, deforestation and climate change. Unfortunately, ground measurements of tree properties such as mass...
journal article 2017
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van den Engel, P.J.W. (author), Kurvers, S.R. (author)
An overview is given of recent developments in the use of a system of inducing natural air supply via the façade in the Netherlands. This is followed by a review of the results of measurements from climate chamber experiments of its inducing ventilation performance and detailed insights gained from related experiments of climate chamber...
journal article 2017
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Radermacher, M. (author), De Wit, L. (author), Uijttewaal, W.S.J. (author), Winterwerp, J.C. (author)
When dredging in sensitive environments, efforts have to be made to limit the free dispersal of suspended fine sediment from the dredging spill. Especially the use of hanging silt curtains as an environmental mitigation measure is widespread. Despite frequent application, their ability to reduce turbidity levels through vertical diversion of...
journal article 2015
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Tomas, J.M. (author), Pourquie, M.J.B.M. (author), Jonker, H.J.J. (author)
Predicting pollutant dispersion in urban environments requires accurate treatment of obstacle geometry, inflow turbulence and temperature differences. This paper considers both the influence of thermal stratification and the presence of a single obstacle on pollutant dispersion in turbulent boundary layers (TBLs). Turbulent flow over a fence...
journal article 2015
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Boersma, B.J. (author), Pecnik, R. (author), Nemati, H. (author), Peeters, J.W.R. (author)
In this paper we discuss the effect of sharp property variations on the turbulent heat transfer in fluids close the critical point. The governing equations for this flow regime are discussed, a short description of the numerical tools that have been developed to study these flows is given. Finally, some results for supercritical heat transfer in...
journal article 2015
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Ambesi, D. (author), Kleijn, C.R. (author), Den Hartog, E.A. (author), Bouma, R.H.B. (author), Brasser, P. (author)
In chemical, biological, radiological, and nuclear protective clothing, a layer of activated carbon material in between two textile layers provides protection against hazardous gases. A cylinder in cross flow, sheathed by such material, is generally used to experimentally test the garment properties. This is, however, complicated and predictive...
journal article 2013
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Burchard, H. (author), Schuttelaars, H.M. (author), Rockwell Geyer, W. (author)
In this idealized numerical modeling study, the composition of residual sediment fluxes in energetic (e.g., weakly or periodically stratified) tidal estuaries is investigated by means of one-dimensional water column models, with some focus on the sediment availability. Scaling of the underlying dynamic equations shows dependence of the results...
journal article 2013
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Violato, D. (author), Scarano, F. (author)
The three-dimensional behavior of jet core breakdown is investigated with experiments conducted on a free water jet at Re = 5000 by time-resolved tomographic particle image velocimetry (TR-TOMO PIV). The investigated domain encompasses the range between 0 and 10 jet diameters. The characteristic pulsatile motion of vortex ring shedding and...
journal article 2013
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Lay-Ekuakille, A. (author), Palamara, I. (author), Caratelli, D. (author), Morabito, F.C. (author)
Subterranean waters are often polluted by industrial and anthropic effluents that are drained in subsoil. To prevent and control pollution, legislations of different developed countries require an online monitoring measurement, especially for detecting organic solvents (chlorinated and unchlorinated ones). Online measurements include both real...
journal article 2013
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Eckhardt, B.E. (author)
The study of the transition to turbulence in parallel shear flows without linear instability of the laminar profile has profited immensely from the application of dynamical systems ideas. Studies of the transition in plane Couette flow and pipe flow, in particular, have shown that the transition is connected with the appearance of 3-d coherent...
journal article 2012
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Winterwerp, J.C. (author), Van Kesteren, W.G.M. (author), Van Prooijen, B.C. (author), Jacobs, W. (author)
This paper proposes a conceptual framework for erosion of cohesive sediment beds. We focus on cohesive beds, distinguishing between floc erosion, surface erosion, and mass erosion. By (our) definition, surface erosion is a drained soil mechanical process, whereas mass erosion occurs under undrained conditions. The eroding shear stress is modeled...
journal article 2012
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Trip, R. (author), Kuik, D.J. (author), Westerweel, J. (author), Poelma, C. (author)
The transitional regime of a sinusoidal pulsatile flow in a straight, rigid pipe is investigated using particle image velocimetry. The main aim is to investigate how the critical Reynolds number is affected by different pulsatile conditions, expressed as the Womersley number and the oscillatory Reynolds number. The transition occurs in the...
journal article 2012
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Violato, D. (author), Scarano, F. (author)
The three-dimensional behavior of flow transition in circular and 6-chevron jets at Re?=?5000 is investigated with experiments conducted on a free water jet by time-resolved tomographic particle image velocimetry. The emphasis is on the unsteady organization of coherent flow structures, which play a role in the generation of acoustic noise....
journal article 2011
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Sathe, A. (author), Mann, J. (author), Gottschall, J. (author), Courtney, M.S. (author)
Modeling of the systematic errors in the second-order moments of wind speeds measured by continuouswave (ZephIR) and pulsed (WindCube) lidars is presented. These lidars use the conical scanning technique to measure the velocity field. The model captures the effect of volume illumination and conical scanning. The predictions are compared with the...
journal article 2011
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Kenjeres, S. (author)
Motivated by the concept of interdependency of turbulent flow and electromagnetic fields inside the spiraling galaxies, we explored the possibilities of generating a localized Lorentz force that will produce a three-dimensional swirling flow in weakly conductive fluids. Multiple vortical flow patterns were generated by combining arrays of...
journal article 2011
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Dijkstra, J.T. (author), Uittenbogaard, R.E. (author)
Aquatic vegetation has an important role in estuaries and rivers by acting as bed stabilizer, filter, food source and nursing area. However, macrophyte populations worldwide are under high anthropogenic pressure. Protection and restoration efforts will benefit from more insight into the interaction between vegetation, currents, waves and...
journal article 2010
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Sukhodolov, A.N. (author), Schnauder, I. (author), Uijttewaal, W.S.J. (author)
Shallow lateral shear layers forming between flows with different velocities, though essential for mixing processes in natural streams, have been examined only in laboratory settings using smooth, fixed?bed channels. This paper reports the results of an experimental study of a shear layer in a straight reach of a natural river where the layer,...
journal article 2010
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Fraanje, P.R. (author), Rice, J. (author), Verhaegen, M. (author), Doelman, N. (author)
Efficient and optimal prediction of frozen flow turbulence using the complete observation history of the wavefront sensor is an important issue in adaptive optics for large ground-based telescopes. At least for the sake of error budgeting and algorithm performance, the evaluation of an accurate estimate of the optimal performance of a particular...
journal article 2010
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Van Balen, W. (author), Uijttewaal, W.S.J. (author), Blanckaert, K. (author)
Large-eddy simulation (LES) is performed of a curved open-channel flow over topography based on the laboratory experiment by Blanckaert [“Topographic steering, flow circulation, velocity redistribution and bed topography in sharp meander bends,” Water Resour. Res., doi:10.1029/2009WR008303 (in press)] . In the experiment, the large-scale bed...
journal article 2010
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