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Tosto, F. (author), Wheeler, Andrew (author), Pini, M. (author)In this work, we investigate the sources of dissipation in adiabatic boundary layers of non-ideal compressible fluid flows. Direct numerical simulations of transitional, zero-pressure gradient boundary layers are performed with an in-house solver considering two fluids characterized by different complexity of the fluid molecules, namely air...book chapter 2023
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Pierzyna, Maximilian (author), Saathof, R. (author), Basu, S. (author)Free-Space Optical Communication (FSOC) links are considered a key technology to support the increasing needs of our connected, data-heavy world, but they are prone to disturbance through atmospheric processes such as optical turbulence. Since turbulence is highly dependent on local topographic and meteorological conditions, modeling optical...conference paper 2023
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Agresti, A. (author)This paper is concerned with the problem of regularization by noise of systems of reaction–diffusion equations with mass control. It is known that strong solutions to such systems of PDEs may blow-up in finite time. Moreover, for many systems of practical interest, establishing whether the blow-up occurs or not is an open question. Here we...journal article 2023
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Zoppini, G. (author), Michelis, Theodorus (author), Ragni, D. (author), Kotsonis, M. (author)This work presents the first experimental characterization of the flow field in the vicinity of periodically spaced discrete roughness elements (DRE) in a swept wing boundary layer. The time-averaged velocity fields are acquired in a volumetric domain by high-resolution dual-pulse tomographic particle tracking velocimetry. Investigation of...journal article 2023
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Grabe, Cornelia (author), Jäckel, Florian (author), Khurana, Parv (author), Dwight, R.P. (author)Purpose: This paper aims to improve Reynolds-averaged Navier Stokes (RANS) turbulence models using a data-driven approach based on machine learning (ML). A special focus is put on determining the optimal input features used for the ML model. Design/methodology/approach: The field inversion and machine learning (FIML) approach is applied to...journal article 2023
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Avallone, F. (author), Ragni, D. (author)Noise reduction is one of the major challenges to the societal acceptance of wind turbines. Aerodynamic noise sources are the dominant ones, assuming that mechanical noise can be reduced by correct insulation and periodic maintenance of the gearbox and drive train and by adding insulating material in the wind-turbine nacelle. The dominant...book chapter 2023
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Vis, Gijs (author)Experiments using fiber-optical set-ups for distributed temperature sensing (DTS) were conducted in the LIAISE (Land surface Interactions with the Atmosphere over the Iberian Semi-arid Environment) field campaign during 15-30 July 2021 in the north-east of Spain. Three DTS set-ups were installed to measure temperature profiles along varying...master thesis 2022
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Miori, Nicolò (author)Recent years have seen an increase in studies focusing on data-driven techniques to enhance modelling approaches like the two-equation turbulence models of Reynolds-averaged Navier-Stokes (RANS). Different techniques have been implemented to improve the results from these simulations. In particular, the main focus has been on overcoming the...master thesis 2022
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van Leeuwen, Elske (author)Computational Fluid Dynamics (CFD) is the main tool to use in industry and engineering problems including turbulent flows. Turbulence modeling relies on solving the Navier-Stokes equations. Solving these equations directly takes a lot of time and computational power. More affordable methods solve the Reynolds Averaged Navier-Stokes (RANS)...master thesis 2022
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JAWAHAR, SAHANA (author)Flat surfaces with arrays of wall-normal pores called micro-cavity arrays have shown potential to reduce turbulent skin friction drag. Their designs have been inspired by acoustic liners which are sandwich panels consisting of a honeycomb core, a perforated top plate and a solid back sheet used on...master thesis 2022
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DIMOU, KYPRIANOS (author)Nowadays, climate change and global warming phenomena are becoming more and more serious issues. In order to sustain the enormous worldwide energy demand, society consumes a high amount of fuel, resulting into the steep increase of the level of CO\textsubscript{2} in the environment. Therefore, the massive greenhouse gases emissions in the...master thesis 2022
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Gołyska, Urszula (author)Abrupt and rapid high-amplitude changes in a dynamical system’s states known as extreme events appear in many processes occurring in nature, such as drastic climate patterns, rogue waves, or avalanches. These events often entail catastrophic effects, therefore their description and prediction is of great importance. Nevertheless, because of...master thesis 2022
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Blishchik, A. (author)Steel is found irreplaceable in many industrial applications. It is currently predicted that steel consumption will increase significantly in the coming decades. Humanity is expected to produce more and more steel-based products, such as cables, cars, railways, bridges, stadiums, skyscrapers, etc. The increased demand will pose a serious...doctoral thesis 2022
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Franx, Marius (author)The ramifications of plastic pollution on the environment are becoming increasingly serious in various forms throughout the world. In this context, rivers are the most important suppliers of plastics entering the marine environment. However, rivers that contain high loads of plastic waste also directly harm the livelihoods of people living near...master thesis 2022
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Raju, Darshan (author)The energy transition from fossil fuels to renewable energy sources is crucial for climate resilience. In particular, hydrogen combustion in gas turbine combustors is expected to play an essential role in the energy transition. Hence, a fuel-flexible gas turbine combustor operating with a wide range of natural gas and hydrogen fuels is necessary...master thesis 2022
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van de Krol, Bart (author)The most used RANS-model in relation to wind farms, k−epsilon, has significant shortcomings. It over-predicts the eddy viscosity in the near-wake and fails to model the anisotropy of the turbulence quantities. The Sparse Regression of the Turbulence Stress Anisotropy (SpaRTA) method could remedy these shortcomings. This method uses temporally...master thesis 2022
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Carrasco Grau, Julio (author)In the last decades, the prevailing belief that smooth surfaces offer the lowest drag has been challenged often. Scholars have, for example, introduced rough and modified surfaces to reduce turbulent skin friction. One of the technologies proposed in the literature is an array of chevron-shaped protrusions; however, there is no academic...master thesis 2022
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VOULTSOS, IOANNIS (author)The energy transition towards carbon neutrality requires a rapid electrification of all energy sectors by 2050. In the EU-27, the REPowerEU strategy, initiated in March 2022, is pursuing this target even more ambitiously. However, in order to achieve the aforementioned goals, the increasing demand for green hydrogen will...master thesis 2022
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Lin, J. (author)Estuaries are the core area of land-sea interactions and have significant ecological and economic value. In estuaries, hydrodynamics and sediment dynamics are the crucial processes governing geomorphology, navigability, and primary production. Since the turn of the 20th century, increased human activities (e.g., damming, dredging, and...doctoral thesis 2022
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Siebols, Renko (author)An experimental study is presented towards inner-scaled Helmholtz-Resonators (HRs) as a passive turbulent boundary layer (TBL) flow control method. Using acoustic pressure-velocity coupling at the orifice of the HR, it is aimed to attenuate the kinetic energy of the grazing turbulence to reduce the mean skin friction. The HRs are tuned towards...master thesis 2022