Searched for: subject%3A%22boundary%255C+layer%22
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van Campenhout, O.W.G. (author)
Any reduction in vehicle drag or fluid resistance provides a potential of substantial energy savings, with obvious benefits to the economy, environment and overall industrial competitiveness. Although various experimental studies have confirmed the potential drag reduction of dimpled surfaces in a turbulent boundary layer (BL), the working...
master thesis 2016
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Hartuç, T. (author)
In this thesis both Wake Ingestion (WI) and Boundary Layer Ingestion (BLI) configurations have been investigated and analyzed with respect to their application to aircraft design. WI and BLI in the context used here means positioning the engine such that it ingests boundary layer fluid for the purpose of saving shaft-power. This research...
master thesis 2015
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Kokkedee, Jop (author)
With an ever increasing demand for sustainable energy, limitations of current sustainable technologies are studied widely. In wind farms, the so-called wake effect provides the biggest limitation on wind farm total power output. Using wind from the unaffected boundary layer to re-energize the wind flow in the wake provides a method of limiting...
master thesis 2022
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van den Ende, I.C. (author)
This study investigates wave driven onshore sandbar migration. Observations show that sandbars move onshore during mild wave conditions. Literature describes different potential sediment mechanisms that cause this onshore migration, but the dominant cause is still under debate. The goal of the present study is to determine the dominant sediment...
master thesis 2017
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De Petter, Christophe (author)
Shock-Wave/Turbulent-Boundary Layer Interactions (SWTBLI) often occur in applications of technological interest. The associated inherent low-frequency unsteadiness dictates the use of Large-Eddy Simulation (LES) approaches to resolve the interaction, which unavoidably implies a very high computational cost. For this reason, no well-resolved long...
master thesis 2019
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Nedumaran, A.K. (author)
Vortex Generators (VGs) are flow control devices commonly applied in wind turbine blades, among other applications. A significant advance in the design of wind turbine blades would be the integration of vortex generators in the aerofoil optimisation process. Currently, aerofoil optimisation relies on either computational fluid dynamics or...
master thesis 2016
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Ramaswamy, Deepak Prem (author)
One of the major challenges that engineers face when designing a high speed vehicle is aerodynamics heating. While ideally the external surfaces are expected to maintain a smooth profile, this is not the case in most vehicles, which might be laden with discontinuities like steps, gaps, and other protrusions. These could alter the local flow...
master thesis 2017
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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
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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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Mukhopadhyay, S.K. (author)
Although significant strides have been made with regards to increasing the fuel economy of commercial passenger aircraft, the reduction of the environmental footprint remains of the utmost importance. The flow development over an aero-engine spinner will affect the velocity distribution over the fan of the engine and this affects the estimation...
master thesis 2020
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SARAKATSANIS, CHRISTOS (author)
The idea of using hydrogen as a medium for storing excess renewable energy is gathering momentum but to deliver, several technological advances are required. One of the main challenges is boundary layer flame flashback (BLF) as a key operability issue for low NO<sub>x</sub> premixed combustion of hydrogen-enriched fuels; thus design of tools to...
master thesis 2020
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Angka Bayu Putranto, Angka (author)
This thesis concerns a numerical investigation for the stabilization (delay of laminar-to-turbulent transition) of ows over a at plate with a meta-unit of a possible metamaterial. The type of instability studied is that due to small disturbances in an incompressible, two-dimensional boundary layer. The linear growth of the disturbance in the...
master thesis 2021
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Sequeira, Aaron (author)
Laminar-to-turbulent boundary layer transition on the wings and stabilizers of aircraft leads to a large increase in the skin-friction drag they experience during flight. This has motivated prolific research into understanding and delaying the transition process, in an effort to improve the economic and ecological impact of air travel. The swept...
master thesis 2022
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Dijkshoorn, Dominic (author)
Organic Rankine Cycle (ORC) Power Plants can be of greatimportance in the energy transition as they are suitable for converting wasteheat to power and can utilize renewable energy for their operation. To improvethe efficiency of ORC Power Plants, the physical phenomena inside thesemachines must be understood....
master thesis 2020
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Chaves García-Mascaraque, Adrián (author)
A formulation based on the evaluation of power conversions within the system allows to overcome the limitations of conventional momentum analyses to study tightly coupled airframe-propulsion configurations such as Boundary Layer Ingestion. The so-called power balance method is applied in a CFD framework to gain insight about the application of...
master thesis 2021
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Makaveev, Momchil (author)
This project proposes and evaluates a novel concept for an airspeed instrument aimed at small hybrid unmanned aerial vehicles. The working principle is to relate the power spectra of the wall-pressure fluctuations beneath the turbulent boundary layer formed over the vehicle’s body to its airspeed. The instrument consists of two microphones,...
master thesis 2023
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Kukučka, Tomas (author)
Boundary Layer Ingestion (BLI) is a promising technology for reducing the impact of aviation on the environment. By placing a propulsor on an aircraft such that it ingests the slower moving air within the boundary layer, a decrease in power consumption can be achieved. Evaluating the performance of BLI configurations remains a challenge though....
master thesis 2023
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Van Arnhem, N. (author)
Boundary Layer Ingestion is an integrated propulsion concept in which a propulsor operates in boundary layer flow instead of the free streamflow with the goal to reduce the fuel flow for a given operating condition. The objective of this thesis is to obtain a better understanding of the power benefit of an installed pusher propeller at the aft...
master thesis 2015
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Arkesteijn, Joerie (author)
Following recent proof of swept wing laminar-to-turbulent boundary layer transition delay through base-flow modification using AC-DBD plasma actuators, an experimental investigation is performed to study the responsible physical mechanism. An experiment is conducted on a 45° swept wing in the anechoic wind tunnel at the Delft University of...
master thesis 2021
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Garg, Sparsh (author)
It is the need of the hour to focus research and development towards curbing emissions due to the growing aviation industry. Employing boundary layer Ingesting(BLI) propellers for development of propulsive fuselage concept(PFC) aircraft while utilizing hydrogen as an alternative energy source, is the idea behind project APPU(Advanced Propulsion...
master thesis 2022
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