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Baas, Peter (author), Verzijlbergh, R.A. (author), van Dorp, Pim (author), Jonker, H.J.J. (author)As a consequence of the rapid growth of the globally installed offshore wind energy capacity, the size of individual wind farms is increasing. This poses a challenge to models that predict energy production. For instance, the current generation of wake models has mostly been calibrated on existing wind farms of much smaller size. This work...journal article 2023
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Koning, A.M. (author), Nuijens, Louise (author), Bosveld, F. C. (author), Siebesma, A.P. (author), van Dorp, P. A. (author), Jonker, H.J.J. (author)This study investigates how wind shear and momentum fluxes in the surface- and boundary layer vary across wind and cloud regimes. We use a 9-year-long data set from the Cabauw observatory complemented by (8.2 × 8.2 (Formula presented.)) daily Large Eddy Simulation (LES) hindcasts. An automated algorithm classifies observed and simulated days...journal article 2021
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Schrijvers, P.J.C. (author), Jonker, H.J.J. (author), de Roode, S.R. (author), Kenjeres, S. (author)This study investigated the surface temperature, air temperature and mean radiant temperature inside an idealized 2D street geometry during daytime. The goal was to unravel the relative impact of radiative transfer, heat conduction and ventilation to the urban heat budget. A building-resolving simulation model has been used, which represents...journal article 2020
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van der Linden, S.J.A. (author), van de Wiel, B.J.H. (author), Petenko, Igor (author), van Heerwaarden, Chiel C. (author), Baas, P. (author), Jonker, H.J.J. (author)High-resolution large-eddy simulations of the Antarctic very stable boundary layer reveal a mechanism for systematic and periodic intermittent bursting. A nonbursting state with a boundary layer height of just 3 m is alternated by a bursting state with a height of ≈5 m. The bursts result from unstable wave growth triggered by a shear-generated...journal article 2020
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van der Linden, S.J.A. (author), Edwards, John M. (author), van Heerwaarden, Chiel C. (author), Vignon, Etienne (author), Genthon, Christophe (author), Petenko, Igor (author), Baas, P. (author), Jonker, H.J.J. (author), van de Wiel, B.J.H. (author)Observations of two typical contrasting weakly stable and very stable boundary layers from the winter at Dome C station, Antarctica, are used as a benchmark for two centimetre-scale-resolution large-eddy simulations. By taking the Antarctic winter, the effects of the diurnal cycle are eliminated, enabling the study of the long-lived steady...journal article 2019
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Eisma, H.E. (author), Tomas, J.M. (author), Pourquie, M.J.B.M. (author), Elsinga, G.E. (author), Jonker, H.J.J. (author), Westerweel, J. (author)Simultaneous particle-image velocimetry and laser-induced fluorescence combined with large-eddy simulations are used to investigate the flow and pollutant dispersion behaviour in a rural-to-urban roughness transition. The urban roughness is characterized by an array of cubical obstacles in an aligned arrangement. A plane fence is added one...journal article 2018
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Tomas, J.M. (author), Eisma, H.E. (author), Pourquie, M.J.B.M. (author), Elsinga, G.E. (author), Jonker, H.J.J. (author), Westerweel, J. (author)Both large-eddy simulations (LES) and water-tunnel experiments, using simultaneous stereoscopic particle image velocimetry and laser-induced fluorescence, have been used to investigate pollutant dispersion mechanisms in regions where the surface changes from rural to urban roughness. The urban roughness was characterized by an array of...journal article 2017
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- Sullivan, P.P. (author), Weil, J.C. (author), Patton, E.G. (author), Jonker, H.J.J. (author), Mironov, D.V. (author) journal article 2016
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Schalkwijk, J. (author), Jonker, H.J.J. (author), Siebesma, A.P. (author)The low-frequency contribution to the systematic and random sampling errors in single-tower eddy-covariance flux measurements is investigated using large-eddy simulation (LES). We use a continuous LES integration that covers a full year of realistic weather conditions over Cabauw, the Netherlands, and emulate eddy-covariance measurements. We...journal article 2016
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Tomas, J.M. (author), Pourquie, M.J.B.M. (author), Jonker, H.J.J. (author)Large-eddy simulations (LES) are used to investigate the effect of stable stratification on rural-to-urban roughness transitions. Smooth-wall turbulent boundary layers are subjected to a generic urban roughness consisting of cubes in an in-line arrangement. Two line sources of pollutant are added to investigate the effect on pollutant dispersion...journal article 2016
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Dorrestijn, J. (author), Crommelin, D.T. (author), Siebesma, A.P. (author), Jonker, H.J.J. (author), Selten, F. (author)Conditional Markov chain (CMC) models have proven to be promising building blocks for stochastic convection parameterizations. In this paper, it is demonstrated how two different CMC models can be used as mass flux closures in convection parameterizations. More specifically, the CMC models provide a stochastic estimate of the convective area...journal article 2016
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Perrin, V.E. (author), Jonker, H.J.J. (author)The distribution of relative velocities between particles provides invaluable information on the rates and characteristics of particle collisions. We show that the theoretical model of Gustavsson and Mehlig [K. Gustavsson and B. Mehlig, J. Turbul. 15, 34 (2014)], within its anticipated limits of validity, can predict the joint probability...journal article 2015
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Perrin, V.E. (author), Jonker, H.J.J. (author)This study investigates the droplet dynamics at the lateral cloud–environment interface in shallow cumulus clouds. A mixing layer is used to study a small part of the cloud edge using direct numerical simulation combined with a Lagrangian particle tracking and collision algorithm. The effect of evaporation, gravity, coalescence, and the initial...journal article 2015
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Schalkwijk, J. (author), Jonker, H.J.J. (author), Siebesma, A.P. (author), Van Meijgaard, E. (author)Since the advent of computers midway through the twentieth century, computational resources have increased exponentially. It is likely they will continue to do so, especially when accounting for recent trends in multicore processors. History has shown that such an increase tends to directly lead to weather and climate models that readily exploit...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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Schalkwijk, J. (author), Jonker, H.J.J. (author), Siebesma, A.P. (author), Bosveld, F.C. (author)Results are presented of two large-eddy simulation (LES) runs of the entire year 2012 centered at the Cabauw observational supersite in the Netherlands. The LES is coupled to a regional weather model that provides the large-scale information. The simulations provide three-dimensional continuous time series of LES-generated turbulence and clouds,...journal article 2015
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De Roode, S.R. (author), Siebesma, A.P. (author), Dal Gesso, S. (author), Jonker, H.J.J. (author), Schalkwijk, J. (author), Sival, J. (author)A mixed-layer model is used to study the response of stratocumulus equilibrium state solutions to perturbations of cloud controlling factors which include the sea surface temperature, the specific humidity and temperature in the free troposphere, as well as the large-scale divergence and horizontal wind speed. In the first set of experiments, we...journal article 2014
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Perrin, V.E. (author), Jonker, H.J.J. (author)This study investigates the local flow characteristics near droplet-droplet collisions by means of direct numerical simulation of isotropic cloudlike turbulence. The key finding is that, generally, droplets do not collide where they preferentially concentrate. Preferential concentration is found to happen as expected in regions of low enstrophy ...journal article 2014
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Boing, S.J. (author), Jonker, H.J.J. (author), Nawara, W.A. (author), Siebesma, A.P. (author)Mixing processes in deep precipitating cumulus clouds are investigated by tracking Lagrangian particles in a large-eddy simulation. The trajectories of particles are reconstructed and the thermodynamic properties of cloud air are studied using mixing diagrams. The trajectory analysis shows that the in-cloud mixing is entirely dominated by...journal article 2014
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Schalkwijk, J. (author), Jonker, H.J.J. (author), Siebesma, A.P. (author)A modeling framework is developed that extends the mixed-layer model to steady-state cumulus convection. The aim is to consider the simplest model that retains the essential behavior of cumulus-capped layers. The presented framework allows for the evaluation of stationary states dependent on external parameters. These states are completely...journal article 2013
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