- document
-
Hemmes, Jasper (author)When simulating fluids the industry standard is Reynolds averaged Navier-Stokes (RANS). However, the results for certain flows are inaccurate. The main source of error in popular RANS turbulence models is the Boussinesq approximation, assuming a linear relationship between the Reynolds stress anisotropy and the mean rate of strain. Experiments...master thesis 2022
- document
-
van den Bos, Nout (author)Due to the complicated design of nuclear reactors, many complex phenomena can cause points of failure. In the case of nuclear fuel rods, the axial flow that cools the rods can induce vibrations due to the turbulent nature of the flow. Turbulence-induced pressure fluctuations create small but significant vibration amplitudes, which in turn can...master thesis 2022
- document
-
Volker, Thijs-Gerrit (author)Implementation of an Explicit Algebraic Reynolds Stress Model in Isogeometric Analysis for seperating flows using a two-equation k-omega model. The model is verified for simple cases such as homogeneous isotropic decaying turbulence, and the turbulent backward facing stepmaster thesis 2022
- document
-
van Dalen, Lyke (author)In this thesis a method of combined PIV and LIF experiments on the Turbulent/Non-Turbulent interface (TNTI) of a round jet is presented.<br/>By varying the distance from the nozzle in the measurements, the Kolmogorov scale of a large range of Reynolds number (2×10<sup>3</sup> ≤ Re ≤ 48×10<sup>3</sup>) is kept constant, allowing for a constant...master thesis 2022
- document
-
Westheim, Michael (author)Interest in powered flight on Mars has been growing in recent years, and as such new developments are being made in determining the effects the Martian atmosphere has on the flow physics and performance, specifically with regards to similarity parameters: the Reynolds number & the Mach number. This paper aimed to investigate whether the...master thesis 2022
- document
-
Willems, Gersom (author)The growing energy demand and climate change poses a need for alternative energy generation in terms of renewable resources. Renewable energy resources are characterised by their intermittent behaviour. A backup power supply is required that can deliver electricity when the supply from the renewables is not sufficient. Gas turbines operating...master thesis 2022
- document
-
Pathanadka, Chinmaya (author)Aerodynamics has played a significant role in the industry of motorsports in improving the performance and handling of the race car. Rob Smedley, the former head of vehicle performance at Williams Racing stated that - "Where teams have problems is when their development or simulation environment – so CFD [Computational Fluid Dynamics] or wind...master thesis 2022
- document
-
Talice, M. (author), Juretić, Franjo (author), Lahaye, D.J.P. (author)The reduction of emissions from large industrial furnaces critically relies on insights gained from numerical models of turbulent non-premixed combustion. In the article Mitigating Thermal NOx by Changing the Secondary Air Injection Channel: A Case Study in the Cement Industry, the authors present the use of the open-source OpenFoam software...journal article 2022
- document
-
Fehrs, Michael (author), Ritter, Markus (author), Helm, Sebastian (author), Mertens, C. (author)The Pazy Wing test case is a benchmark for the investigation of aeroelastic effects at very large deflections. Tip deformations in the order of 50% span were measured in wind tunnel tests, which renders this model highly attractive for the validation of numerical aeroelastic methods and tools for geometrically nonlinear, large deflection...conference paper 2022
- document
-
Casacuberta Puig, J. (author), Hickel, S. (author), Westerbeek, S.H.J. (author), Kotsonis, M. (author)The interaction between forward-facing steps of several heights and a pre-existing critical stationary crossflow instability of a swept-wing boundary layer is analysed. Direct numerical simulations (DNS) are performed of the incompressible three-dimensional laminar base flow and the stationary distorted flow that arise from the interaction...journal article 2022
- document
-
van der Boog, C.G. (author), Dijkstra, Henk A. (author), Pietrzak, J.D. (author), Katsman, C.A. (author)Because of its pronounced fresh signature, the properties of the northward-flowing Antarctic Intermediate Water (AAIW) affect the Atlantic Meridional Overturning Circulation. Hence, understanding modifications of AAIW along its path is important. Here, we analyze AAIW changes along its path in the Caribbean Sea and assess whether vertical...journal article 2022
- document
-
Stoellinger, Michael (author), Roekaerts, D.J.E.M. (author)The simple semi-empirical precursor soot model of Brookes and Moss based on the soot number density and soot mass concentration is adopted in a transported probability density function (PDF) method for turbulent diffusion flames. The gas phase chemistry is described by a flamelet generated manifold (FGM) based on the mixture fraction,...journal article 2022
- document
-
Arosquipa Nina, Yvan (author), Shi, Rui (author), Wüthrich, D. (author), Chanson, Hubert (author)Self-aerated free-surface flow studies have a more recent history compared to classical fluid dynamics. Traditional velocimetry techniques are adversely affected by the presence of gas–liquid interfaces. In the present study, detailed air-water flow measurements were performed in a highly turbulent free-surface flow, and three velocimetry...journal article 2022
- document
-
Modesti, D. (author), Pirozzoli, Sergio (author)We carry out direct numerical simulations (DNS) of flow in a turbulent square duct by focusing on heat transfer effects, considering the case of unit Prandtl number. Reynolds numbers up to are considered that are much higher than in previous studies, and that yield clear scale separation between inner- and outer-layer dynamics. Close...journal article 2022
- document
-
Ben Hassan Saïdi, Ismaïl (author), Schmelzer, M. (author), Cinnella, Paola (author), Grasso, Francesco (author)A CFD-driven deterministic symbolic identification algorithm for learning explicit algebraic Reynolds-stress models (EARSM) from high-fidelity data is developed building on the frozen-training SpaRTA algorithm of [1]. Corrections for the Reynolds stress tensor and the production of transported turbulent quantities of a baseline linear eddy...journal article 2022
- document
-
van Nesselrooij, M. (author), van Campenhout, O.W.G. (author), van Oudheusden, B.W. (author), Schrijer, F.F.J. (author), Veldhuis, L.L.M. (author)Accurately measuring small changes in aerodynamic drag over a flat surface stands at the core of the development of technologies capable of reducing turbulent friction drag. A wind tunnel drag measurement system was developed which improves significantly on the state of the art. Experimental tests demonstrated that an uncertainty of less than...journal article 2022
- document
-
Rius Vidales, A.F. (author), Kotsonis, M. (author)Experiments have been conducted on a swept wing model in a low-turbulence wind tunnel at chord Reynolds number of to investigate the unsteady interaction of a forward-facing step (FFS) with incoming stationary crossflow (CF) vortices. The impact of varying the FFS height on the development and growth of primary and secondary CF disturbances...journal article 2022
- document
-
Xu, R. (author), Zhou, Xu Hui (author), Han, Jiequn (author), Dwight, R.P. (author), Xiao, Heng (author)In fluid dynamics, constitutive models are often used to describe the unresolved turbulence and to close the Reynolds averaged Navier–Stokes (RANS) equations. Traditional PDE-based constitutive models are usually too rigid to calibrate with a large set of high-fidelity data. Moreover, commonly used turbulence models are based on the weak...journal article 2022
- document
-
Lahaye, D.J.P. (author), Nakate, P.A. (author), Vuik, Cornelis (author), Juretic, F. (author), Talice, Marco (author)The operation of large industrial furnaces will continue to rely on hydrocarbon fuels in the near foreseeable future. Mathematical modeling and numerical simulation is expected to deliver key insights to implement measures to further reduce pollutant emissions. These measures include the design optimization of the burners, the dilution of...journal article 2022
- document
-
Dash, A. (author), Poelma, C. (author)We revisit the laminar–turbulent transition of a fine-grained slurry in a large pipe. The combination of long measurement times in an industrial-scale facility and ultrasound imaging allows us to observe and address anomalous trends. Under turbulent conditions, the flow is homogeneous and steady. However, under laminar conditions, two types of...journal article 2022