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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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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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Gillissen, J.J.J. (author), Boersma, B.J. (author), Mortensen, P.H. (author), Andersson, H.I. (author)Fiber-induced drag reduction can be studied in great detail by means of direct numerical simulation [ J. S. Paschkewitz et al., J. Fluid Mech. 518, 281 (2004) ]. To account for the effect of the fibers, the Navier-Stokes equations are supplemented by the fiber stress tensor, which depends on the distribution function of fiber orientation angles....journal article 2007
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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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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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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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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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Hughes, T.J.R. (author), Wells, G.N. (author), Wray, A.A. (author)Energy transfers within large-eddy simulation (LES) and direct numerical simulation (DNS) grids are studied. The spectral eddy viscosity for conventional dynamic Smagorinsky and variational multiscale LES methods are compared with DNS results. Both models underestimate the DNS results for a very coarse LES, but the dynamic Smagorinsky model is...journal article 2004
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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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Wani, F.M. (author), Shipurkar, U. (author), Dong, J. (author), Polinder, H. (author)This paper compares active and passive cooling systems in tidal turbine power electronic converters. The comparison is based on the lifetime of the IGBT (insulated gate bipolar transistor) power modules, calculated from the accumulated fatigue due to thermal cycling. The lifetime analysis accounts for the influence of site conditions, namely...journal article 2021
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- van Emmerik, T.H.M. (author), Steele-Dunne, S.C. (author), Guerin, Marceau (author), Gentine, Pierre (author), Oliveira, Rafael (author), Hut, R.W. (author), Selker, John (author), Wagner, Jim (author), van de Giesen, N.C. (author) journal article 2018
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Mulder, G. (author), van Leijen, F.J. (author), Hanssen, R.F. (author)The observed phase in time series of interferometric synthetic aperture radar (InSAR) products is a superposition of various components. Differential topography, line-of-sight displacements, and differential atmospheric delays are the main contributions and need to be disentangled to derive accurate digital elevation model (DEM), deformation,...journal article 2023
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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<...journal article 2018
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Abelmann, Leon (author), Hageman, Tijmen (author), Löthman, Per (author), Mastrangeli, Massimo (author), Elwenspoek, Miko (author)Interaction between dipolar forces, such as permanent magnets, generally leads to the formation of one-dimensional chains and rings. We investigated whether it was possible to let dipoles self-assemble into three-dimensional structures by encapsulating them in a shell with a specific shape. We found that the condition for self-assembly of a...journal article 2020
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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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Prades, Lledó (author), Fabbri, Stefania (author), Dorado, Antonio D. (author), Gamisans, Xavier (author), Stoodley, Paul (author), Picioreanu, C. (author)Experimental data showed that high-speed microsprays can effectively disrupt biofilms on their support substratum, producing a variety of dynamic reactions such as elongation, displacement, ripple formation, and fluidization. However, the mechanics underlying the impact of high-speed turbulent flows on biofilm structure is complex under such...journal article 2020
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Löthman, Per A. (author), Hageman, Tijmen A.G. (author), Elwenspoek, Miko C. (author), Krijnen, Gijs J.M. (author), Mastrangeli, Massimo (author), Manz, Andreas (author), Abelmann, Leon (author)The extent to which one can use a thermodynamic description of turbulent flow as a source of stochastic kinetic energy for 3D self‐assembly of magnetically interacting macroscopic particles is investigated. It is confirmed that the speed of the objects in the flow field generated in this system obeys the Maxwell–Boltzmann distribution, and their...journal article 2020
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Burgers, J.M. (author)Lecture notes of prof. Burgers prepared during his sabbatical at CalTech.lecture notes 1951