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Sahoo, A. (author)As the demand for renewable energy increases, wind turbine rotors will become larger with slender blades. Vortex Generators (VGs) are one of the most common methods of passive flow control to avoid flow separation and loading on the root section of slender blades due to their simplicity, inexpensiveness, and the ability to retrofit them to...conference paper 2022
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Thurkow, M. (author), Kirchner, I. (author), Kranenburg, R. (author), Timmermans, R.M.A. (author), Schaap, M. (author)Particulate matter (PM) remains as one of the most relevant air-quality concerns in urban environments. The Berlin agglomeration area is still affected by exceedances of the daily limit value of the PM concentration, especially during wintertime PM episodes. In this study, we present test-case studies with the LOTOS-EUROS CTM to improve the...article 2021
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Ozdemir, H. (author)In this chapter the derivation of the viscous integral boundary layer equations is presented in an unsteady, two-dimensional form. Closure sets for both laminar and turbulent flow conditions together with a laminar to turbulent transition method are given. The solution methods for the inviscid region and the viscous-inviscid interaction coupling...bookPart 2020
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Pandey, S. (author), Houweling, S. (author), Krol, M. (author), Aben, I. (author), Nechita-Banda, N. (author), Thoning, K. (author), Rockmann, T. (author), Yin, Y. (author), Segers, A.J. (author), Dlugokencky, E.J. (author)We quantify the impact of atmospheric transport and limited marine boundary layer sampling on changes in global and regional methane burdens estimate using tracer transport model simulations with annually repeating methane emissions and sinks but varying atmospheric transport patterns. We find the 1σ error due to this transport and sampling...article 2019
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Sprung, D. (author), Sucher, E. (author), van Eijk, A.M.J. (author), Eisele, C. (author), Seiffer, D. (author), Stein, K. (author)A field trial was performed in the arid scrub area of White Sands, NM /USA in October 2017 investigating the atmospheric influence on imaging and sensor performance. In this paper we focus on the strength of optical turbulence. Optical turbulence is described by the structure function parameter of the refractive index Cn 2. It is responsible for...conference paper 2018
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Ullwer, C. (author), Sprung, D. (author), van Eijk, A.M.J. (author), Gunter, W. (author), Stein, K. (author)Atmospheric turbulence impacts on the propagation of electro-optical radiation. Typical manifestations of optical turbulence are scintillation (intensity fluctuations), beam wander and (for laser systems) reduction of beam quality. For longer propagation channels, it is important to characterize the vertical and horizontal distribution ...conference paper 2018
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Sprung, D. (author), van Eijk, A.M.J. (author), Günter, W. (author), Griffith, D. (author), Eisele, C. (author), Sucher, E. (author), Seiffer, D. (author), Stein, K. (author)Atmospheric turbulence impacts on the propagation of electro-optical radiation. Typical manifestations of optical turbulence are scintillation (intensity fluctuations), beam wander and (for laser systems) reduction of beam quality. For longer propagation channels, it is important to characterize the vertical and horizontal distribution ...conference paper 2017
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van Eijk, A.M.J. (author), Sprung, D. (author), Sucher, E. (author), Eisele, C. (author), Seiffer, D. (author), Stein, K. (author)Optical turbulence for over-water conditions was investigated in a long-term experiment over False Bay near Cape Town, South Africa. A sonic anemometer and two boundary-layer scintillometers were deployed to access in-situ turbulence as well as the integrated turbulence over two 1.8 and 8.7 km paths. Statistical analysis reveals spatial temporal...conference paper 2016
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Pfahl, A. (author), Randt, M. (author), Meier, F. (author), Zaschke, M. (author), Geurts, C.P.W. (author), Buselmeier, M. (author)The AutoR-project takes a holistic approach to reduce the cost of heliostat fields: Wireless control and energy supply enables to use smaller heliostats which need less steel per mirror area (but usually have high wiring cost). A low cost but high efficient drive system is chosen which reduces energy consumption to a minimum amount and leads to...conference paper 2015
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de Jong, A.N. (author), Schwering, P.B.W. (author), Benoist, K.W. (author), Gunter, W.H. (author), Vrahimis, G. (author), October, F.J. (author)For users of Electro-Optical (EO) sensors at sea, knowledge on their resolution is of key operational importance for the prediction of the obtainable classification ranges. Small targets may be located at ranges of 20 km and more and the present day sensor pixel size may be as small as 10 μrad. In this type of scenarios, sensor resolution will...conference paper 2014
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de Jong, A.N. (author), Schwering, P.B.W. (author), van Eijk, A.M.J. (author), Gunter, W.H. (author)Various atmospheric propagation effects are limiting the long range performance of electro-optical imaging systems. These effects include absorption and scattering by molecules and aerosols, refraction due to vertical temperature gradients and scintillation and blurring due to turbulence. In maritime and coastal areas, ranges up to 25 km are...article 2013
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Wilson, C. (author), van Eijk, A.M.J. (author), Fedorovich, E. (author)A methodology is presented to infer the refractive-index structure function parameter and the structure parameters for temperature and humidity from numerical simulations of the turbulent atmospheric convective boundary layer (CBL). The method employs spatial and temporal averaging of multiple realizations of the CBL flow field reproduced by a...conference paper 2013
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de Jong, A.N. (author), Schwering, P.B.W. (author), Gunter, W.H. (author), Vrahimis, G. (author), October, F.J. (author)The knowledge on scintillation, caused by atmospheric turbulence, is of vital importance for the performance prediction of threat detection systems and for the development of associated detection algorithms. Additionally, scintillation data may support the knowledge on turbulence characteristics. Along these ideas, data have been analysed,...conference paper 2012
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de Jong, A.N. (author), van Eijk, A.M.J. (author), Benoist, K.W. (author), Gunter, W.H. (author), Vrahimis, G. (author), October, F.J. (author)Knowledge on the marine boundary layer is of importance for the prediction of the optical image quality obtained from long range targets. One property of the boundary layer, that can be studied rather easily by means of optical refraction measurements, is the vertical temperature profile. This profile can be compared with the profile, as...conference paper 2011
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aan de Brugh, J.M.J. (author), Henzing, J.S. (author), Schaap, M. (author), Morgan, W.T. (author), Coe, H. (author), Krol, M.C. (author)An explanatory model study is presented on semi-volatile secondary inorganic aerosols on three clear days in May 2008 during the IMPACT campaign at the Cabauw tower in the Netherlands. A single column model in combination with the equilibrium aerosol model ISORROPIA is used. This model uses surface observations from IMPACT and calculates the gas...article 2011
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Hulsbosch-Dam, C.E.C. (author), Spruijt, M.P.N. (author), Trijssenaar-Buhre, I.J.M. (author)A large release of Carbon Dioxide (CO<inf>2</inf>) is modelled with Computational Fluid Dynamics (CFD), (Fluent v12.1). Special attention is given to the modelling of a neutral atmospheric boundary layer (ABL) with gravity. Both the presence of non-vapour CO<inf>2</inf> and the high density of CO<inf>2</inf> require that the effect of gravity is...conference paper 2011
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Gibbs, J.A. (author), Fedorovich, E. (author), van Eijk, A.M.J. (author)Weather Research and Forecasting (WRF) model predictions using different boundary layer schemes and horizontal grid spacings were compared with observational and numerical large-eddy simulation data for conditions corresponding to a dry atmospheric convective boundary layer (CBL) over the southern Great Plains (SGP). The first studied case...article 2011
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Swart, A. (author), Manders, A. (author), Harlander, U. (author), Maas, L.R.M. (author), TNO Bouw en Ondergrond (author)This paper reports on experimental observation of internal waves that are focused due to a sloping topography. A remarkable mixing of the density field was observed. This result is of importance for the deep ocean, where internal waves are believed to play a role in mixing. The experiments were performed on the rotating platform at the Coriolis...article 2010
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Roelofs, G.-J. (author), ten Brink, H. (author), Kiendler-Scharr, A. (author), de Leeuw, G. (author), Mensah, A. (author), Minikin, A. (author), Otjes, R. (author), TNO Bouw en Ondergrond (author)In May 2008, the measurement campaign IMPACT for observation of atmospheric aerosol and cloud properties was conducted in Cabauw, The Netherlands. With a nudged version of the coupled aerosol-climate model ECHAM5-HAM we simulate the size distribution and chemical composition of the aerosol and the associated aerosol optical thickness (AOT) for...article 2010
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Roelofs, G.-J. (author), ten Brink, H. (author), Kiendler-Scharr, A. (author), de Leeuw, G. (author), Mensah, A. (author), Minikin, A. (author), Otjes, R. (author), TNO Bouw en Ondergrond (author)In May 2008 the measurement campaign IMPACT for observation of atmospheric aerosol and cloud properties was conducted in Cabauw (The Netherlands). With a nudged version of the coupled aerosol-climate model ECHAM5-HAM we simulate aerosol and aerosol optical thickness (AOT) for the campaign period. Synoptic scale meteorology is represented...article 2010