Searched for: subject:"turbulence"
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Zhang, Yu (author), Dwight, R.P. (author), Schmelzer, M. (author), Gómez, Javier F. (author), Han, Zhong hua (author), Hickel, S. (author)
Multi-fidelity optimization methods promise a high-fidelity optimum at a cost only slightly greater than a low-fidelity optimization. This promise is seldom achieved in practice, due to the requirement that low- and high-fidelity models correlate well. In this article, we propose an efficient bi-fidelity shape optimization method for...
journal article 2021
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Belligoli, Z. (author)
The continuous increase in the number of flights in the last decades caused a steepgrowth of aviation-related pollution to the point that the aviation sector is responsible for3% of the global greenhouse gas emissions. Regulators have been slow at catching up withthis problem, and stringent emission targets have been put in place only very...
doctoral thesis 2021
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van Put, Max (author)
<br/>This study presents the numerical modeling of boundary layer flame flashback in premixed tube burners with turbulent flow and high hydrogen content. The modeling approach is based on a RANS turbulence model and a flamelet combustion model using a flame surface density approach in combination with multiple turbulent flame speed correlations...
master thesis 2021
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Lai, Yu-Jui (author)
This research studies the fluid-structure interaction (FSI) of compliant surfaces in air flows, with an objective of finding possible turbulent viscous drag reduction. A compliant surface is a thin layer of viscoelastic material drawing inspiration from dolphin epidermis, which was thought to have drag-reducing capabilities by Gray (1936)....
master thesis 2021
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Otero Rodriguez, G.J. (author)
The global temperature rise, which directly results from greenhouse gases emitted by burning fossil fuels, requires humanity to harness renewable energy sources at an increased rate. However, renewable energy sources are either highly intermittent, such as wind and solar radiation, or available at low temperatures leading to low efficiencies of...
doctoral thesis 2021
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Ghauri, Rameen (author)
Wind turbines installed in a wind farm are typically subject to increased turbulence because they are in the wake of upstream wind turbines that generate additional turbulence. Accurate prediction of turbulence in wind farms is critical as it is proportional to wind turbine fatigue loads, power losses and prediction of wind farm lifetime. IEC...
master thesis 2021
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Lin, Yuyu (author)
Dimples are shallow, indented surfaces that attempt to reduce drag in turbulent boundary layer flows. However, the underlying effect of the dimples on the drag is not entirely understood. This thesis sets out to expand our understanding; a numerical investigation of turbulent boundary layer flow over dimpled surfaces is conducted. This research...
master thesis 2021
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van der Voort Maarschalk, Joost (author)
Drag in pipelines is composed almost solely of skin friction drag. The most common technique to achieve drag reduction (DR) is by adding drag-reducing agents. However, in the aerospace industry, various impressive passive drag-reducing techniques have been suggested to reduce skin friction drag in the past decades. Among these techniques,...
master thesis 2021
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Wegman, Tess (author)
Due to climate change and human interventions, saltwater intrusion is becoming a topic of increasing concern worldwide. Salt water intrudes into the Rotterdam Waterway (RWW) by an exchange flow, where the denser sea water propagates landwards at the bottom. The main competing mechanism for this stratified exchange flow is...
master thesis 2021
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Ren, Mengmeng (author), Wang, Shuzhong (author), Romero-Anton, N. (author), Zhao, Junxue (author), Zou, Chong (author), Roekaerts, D.J.E.M. (author)
Eddy dissipation concept (EDC) model and flamelet generated manifolds (FGM) model are developed separately to study the temperature profiles and extinction limits of non-premixed hydrothermal flames. Predictions by the two models are evaluated comparatively by experimental data in literatures. FGM model shows relatively better prediction of...
journal article 2021
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Reurings, C. (author), Koussios, S. (author), Bergsma, O.K. (author), Vergote, K. (author), Paeshuyse, L. (author), Benedictus, R. (author)
A realistic wear test was developed for porous thermal insulation systems exposed to high temperature turbulent gas flow, because it is essential for the development of existing and new concepts of such insulation and therefore also for the performance of processes that depend on such insulation. Wear is crucial and often dominant for the...
journal article 2021
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Teruna, C. (author), Avallone, F. (author), Casalino, D. (author), Ragni, D. (author)
A lattice-Boltzmann method has been employed to study the aeroacoustics and aerodynamics of airfoils equipped with leading edge treatments, namely the porous leading edge and leading edge serrations. The present study aims to identify the differences in noise reduction mechanisms between the two treatments. Within the context of...
journal article 2021
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Berghout, Pieter (author), Baars, W.J. (author), Krug, Dominik (author)
Turbulent convection systems are known to give rise to prominent large-scale circulation. At the same time, the 'background' (or 'small-scale') turbulence is also highly relevant and e.g. carries the majority of the heat transport in the bulk of the flow. Here, we investigate how the small-scale turbulence is interlinked with the large-scale...
journal article 2021
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Samie, M. (author), Baars, W.J. (author), Rouhi, A. (author), Schlatter, P. (author), Örlü, R. (author), Marusic, I. (author), Hutchins, N. (author)
Opposition-control of the energetic cycle of near wall streaks in wall-bounded turbulence, using numerical approaches, has shown promise for drag reduction. For practical implementation, real-time opposition control is only realizable if there is a degree of coherence between the turbulent velocities passing a sensor and the target point...
journal article 2020
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Reijtenbagh, Jesse (author)
Turbulent scalar mixing is prominent in all sorts of situations, being it in air pollution or making tea. However, this does not often lead to a homogeneously mixed fluid, but rather leads to regions of higher concentrations next to regions with significantly lower concentrations. This can be characterized by dividing the concentration field in...
master thesis 2020
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Krishnan, Vasudevan (author)
Multiphase flows are found in abundant natural phenomena and industrial processes. In particular, pipe flows are widely popular in industries involving chemical processing, dredging, and oil transport to name a few. Particle laden flows are often observed in applications like dredging, sediment, and slurry transport through pipes, etc. Therefore...
master thesis 2020
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Steijger, C.A.N. (author)
Heat transfer via thermal radiation is a common occurrence in industry; be it in flue gas, boilers, reactors, or in supersonic combustor such as in a scramjet propulsion. <br/>Numerous studies have been done regarding the phenomena interacting with thermal radiation in different types of turbulent flows. <br/><br/>For compressible flows the...
master thesis 2020
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Pazhev, Ventsislav (author)
Transverse jet injection into supersonic crossflows is encountered with Aerospace applications such as fuel injection in Supersonic Combustion Ramjet (SCRamjet) engines and reaction-jet-based attitude control systems. In particular, for the case of SCRamjets, the short residence times of the fuel in the combustion chamber can be countered by the...
master thesis 2020
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Greidanus, A.J. (author)
This thesis describes the investigation of the dynamics of turbulent shear flows over non-smooth surfaces. The research was conducted in two parts, related to the experimental facility used in combination with the applied functional surface. The first part describes the experiments of a turbulent Taylor-Couette flow over a...
doctoral thesis 2020
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Alinaghi, Pouriya (author)
In the well-known process of the turbine design, turbulence intensity (TI) plays a vital role in prediction of the power output and loads on the turbine's structure. TI is believed to be an important statistical parameter of the wind speed that can be extracted from the signals recorded by the dedicated sensors in the wind energy area. Despite...
student report 2020
Searched for: subject:"turbulence"
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