- document
-
Mak, Ho Yi Lydia (author)In the atmospheric boundary layer, when surface heat flux is small and mean wind shear is strong, horizontal convective rolls that are elongated along the wind shear are formed. This study attempts to explain the asymmetry of rolls in terms of turbulence using large-eddy simulations. A pressure gradient in the north-south y direction is applied,...student report 2023
- document
-
Jose, Nikhil (author)Surfaces that induce slip at the wall have been shown to reduce skin friction drag in the turbulent regime. While superhydrophobic and liquid-infused surfaces are capable of drag reduction in turbulent hydrodynamic flows, neither would be feasible in aerodynamic applications due to the added roughness and the minuscule slip lengths created by...master thesis 2023
- document
-
Krol, Robert (author)Silicon based power semiconductors have long been used as the standard in ‘semiconductor technology in power conversion applications’. Recent developments replaces the Silicon with Silicon Carbide as it results in superior performance of the power conversion applications. However, due to the increased performance, challenges...master thesis 2023
- document
-
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
- document
-
Zamponi, R. (author), Satcunanathan, S. (author), Moreau, S. (author), Meinke, M. (author), Schröder, W. (author), Schram, C. (author)Integrating a porous material into the structure of an aerofoil constitutes a promising passive strategy for mitigating the noise from turbulence–body interactions that has been extensively explored in the past few decades. When a compact permeable body is considered in the aeroacoustic analogy derived by Curle to predict this noise source, a...journal article 2023
- document
-
Bernardini, Matteo (author), Modesti, D. (author), Salvadore, Francesco (author), Sathyanarayana, Srikanth (author), Della Posta, Giacomo (author), Pirozzoli, Sergio (author)We present STREAmS-2.0, an updated version of the flow solver STREAmS, first introduced in Bernardini et al. (2021) [1]. STREAmS-2.0 has an object-oriented design which separates the physics equations from the specific back-end, making the code more suitable for future expansions, such as porting to novel computing architectures or...journal article 2023
- document
-
Noel, L.F.P. (author), Maute, K. (author)Solving conjugate heat transfer design problems is relevant for various engineering applications requiring efficient thermal management. Heat exchange between fluid and solid can be enhanced by optimizing the system layout and the shape of the flow channels. As heat is transferred at fluid/solid interfaces, it is crucial to accurately resolve...journal article 2023
- document
-
Spitzer, Stefan H. (author), Askar, Enis (author), Benke, Alexander (author), Cloney, Chris (author), D'Hyon, Sebastian (author), Dufaud, Olivier (author), Dyduch, Zdzislaw (author), Gabel, Dieter (author), Taveau, J.R. (author)There is no applicable existing standard for the determination of safety characteristics for hybrid mixtures. While developing a new standard in a joint research project in Germany first results from parameter studies led to a standard procedure that can be adopted by laboratories that are already testing dusts in the so called 20L-sphere...journal article 2023
- document
-
Keetels, G.H. (author), Chauchat, Julien (author), Breugem, W.P. (author)Reliable prediction of the erosion rate of sediment beds is important for many applications in coastal and river engineering. Theoretical understanding of empirically derived scaling relations is still lacking. This applies in particular for the scaling anomaly between low and high Shields number conditions. In this work, the erosion process is...journal article 2023
- document
-
van Campenhout, O.W.G. (author), van Nesselrooij, M. (author), Lin, Y. (author), Casacuberta Puig, J. (author), van Oudheusden, B.W. (author), Hickel, S. (author)Although several previous studies have reported a potential drag-reducing effect of dimpled surfaces in turbulent boundary layers, there is a lack of replicability across experiments performed by different research groups. To contribute to the dialogue, we scrutinize one of the most studied dimple geometries reported in the literature, which...journal article 2023
- document
-
Diez Sanhueza, R.G. (author), Smit, S.H.H.J. (author), Peeters, J.W.R. (author), Pecnik, R. (author)This paper presents a machine learning methodology to improve the predictions of traditional RANS turbulence models in channel flows subject to strong variations in their thermophysical properties. The developed formulation contains several improvements over the existing Field Inversion Machine Learning (FIML) frameworks described in the...journal article 2023
- document
-
Makaveev, M.K. (author), Snellen, M. (author), Smeur, E.J.J. (author)This paper puts forward a novel design for an airspeed instrument aimed at small fixed-wing tail-sitter unmanned aerial vehicles. The working principle is to relate the power spectra of the wall-pressure fluctuations beneath the turbulent boundary layer present over the vehicle’s body in flight to its airspeed. The instrument consists of two...journal article 2023
- document
-
Pirozzoli, Sergio (author), Modesti, D. (author)We carry out direct numerical simulations (DNS) of turbulent flow and heat transfer in pressure-driven plane channels, by considering cases with heating on both walls, as well as asymmetric heating limited to one of the channel walls. Friction Reynolds numbers up to are considered, and Prandtl numbers from to, the temperature field being...journal article 2023
- document
-
Hosseini, A. (author), Hage, Johannes (author), Meijer, Koen (author), Offerman, S.E. (author), Yang, Y. (author)In this paper a CFD analysis of HIsarna off-gas system for post combustion of CO-H2-carbon particle mixture is presented to evaluate the effect of different sub-models and parameters on the accuracy of predictions and simulation time. The effects of different mesh type, mesh grid size, radiation models, turbulent models, kinetic mechanism,...journal article 2023
- document
-
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
- document
-
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
- document
-
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
- document
-
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
- document
-
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
- document
-
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