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Showing 1 to 20 of 26 for “"turbulence modelling"”.
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Turbulence Modelling for Complex Flows in Turbomachinery
… (CFD) so that it can be a more reliable tool for modelling complex flows in turbomachinery. To achieve this goal, a three-dimensional (3D) flow phenomenon that embodies many key features of turbomachinery flows, that is, the corner separation flow often found in axial compressor stators, is …
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Turbulence Modelling of Tidal Currents in Rectangular Harbours
In this study turbulence refinements have been made to existing computational models for the prediction of currents and water levels in coastal and estuarine waters via the numerical solution of the depth- and layer-integrated Reynolds equations. As most flows in practice are always turbulent, it …
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Astronomical seeing conditions as determined by turbulence modelling and optical measurement
… of the optical seeing conditions. Atmospheric turbulence in the planetary boundary layer (PBL) contributes significantly to the degradation of optical seeing quality. To evaluate astronomical seeing conditions at a site, a two-sided approach is considered – on the one hand, the use of a …
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Assessment of Turbulence Modelling for Compressibility Effects in Ejector Ramjet Applications
… (CFD) study is presented to assess the k−ω SST turbulence model’s accuracy in representing compressibility effects for a confined supersonic jet, a key component of the Atlantis Intake System ejector ramjet. The third-party OpenFOAM compressible flow solver, pimpleCentralFOAM, is used to …
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Physics-informed machine learning techniques for edge plasma turbulence modelling in computational theory and experiment
Edge plasma turbulence is critical to the performance and operation of magnetic confinement fusion devices. Drift-reduced Braginskii two-fluid theory has for decades been widely applied to model boundary plasmas with varying success. Towards better understanding edge turbulence in both theory and …
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A qualitative assessment and optimization of URANS modelling for unsteady cavitating flows
… it continues to pose a challenge for numerical modelling techniques due to its flow unsteadiness and the cavitation-turbulence interaction. One of the principal aspects to modelling cavitation requires the coupling of a cavitation and a turbulence model. While, scale-resolving turbulence …
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Pressure signature in adverse-pressure-gradient wall bounded turbulent flows
… efficiency. There is a definite lack of turbulence data in the literature for adverse pressure gradient flows with and without separation. Hence, thorough experimental investigation is valuable in developing a fundamental understanding of such complex turbulent flows leading to practical …
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Experimental and numerical studies on oil spilling from damaged oil tankers
… using dynamic mesh technologies; (2) to model turbulence associated with the oil spilling process using various available turbulent models; and (3) to investigate the effects of the compressibility of the fluid. The oil spilling from damaged DHTs is simulated and validated by the experimental …
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Background Flow Influence on Impulsive Jet-Driven Micro Droplet Dispersal
… uses the Eulerian-Lagrangian model with k−ω turbulence modelling to simulate spread of particles and study the factors affecting it in a closed environment with a background flow. Respiratory activities are modeled as a non-isothermal jet of air with droplets suspended in them in a …
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Experimental and numerical investigation of turbulence in Stable Boundary Layer flows
… analyses to improve current understanding of turbulence in stably stratified flows. An extensive literature review is presented on the mechanisms governing turbulence under stratified conditions, with a special focus on the Richardson number parameter, as it is often adopted as a switch to …
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Computations of Turbulent Premixed Flames Using Conditional Moment Closure
… the emission legislation becomes more stringent, modelling of turbulent premixed combustion has become an important tool for designing efficient and environmentally friendlier combustion systems. However, in order to predict these emissions reliable predictive models are required. One of the …
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Investigation of novel electroactive morphing concepts for aerodynamic performance increase of an A320 wing through High-Fidelity numerical simulation
… the lifting structure and the surrounding turbulence by means of large DoFs of the actuators composing the morphing system. The Organised Eddy Simulation turbulence modelling was used to capture the turbulent coherent structures interacting with the chaotic turbulence. A large parametric …
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Unsteady aerodynamics using high-order methods
… Simulation (DES) method is considered for the turbulence modelling part. At the start of this project, the combination of high order Computational Aeroacoustics (CAA) numerical schemes, non-reflecting boundary conditions and DES constituted a state of the art approach to the simulation of …
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CFD modelling of flow-induced vibration under multiphase flow regimes.
… CFD and FEA-based numerical-analytical modelling framework was applied, to predict the defining characteristics of MFIV in the pipes. The CFD simulations of thirty-five cases of slug, cap bubbly and churn turbulent flow-induced fluctuations at the bends were carried out using the volume …
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A numerical study into the effects of turbulent flows around full-scale buildings
… flows around full-scale buildings. Two different turbulence models were considered: a complete Reynolds stress model with two alternative proposals for the pressure-strain correlations and a k-E model used in conjunction with both linear and nonlinear stress-strain relationships. The governing …
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Mathematical Modelling of Acoustic Diffraction Noise Embracing Diverse Boundary Conditions
… we develop advanced mathematical tools for modelling acoustic diffraction noise in various contexts and explore improved models for aerofoil-turbulence interaction noise. The thesis is divided into two parts. The first explores variants of half-plane scattering problems and the analytical …
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Numerical Modelling of Breaking Waves under the Influence of Wind
… air and water simultaneously. Two strategies for turbulence modelling, namely, the Reynolds-averaged Navier–Stokes (RANS) equations with the k−ǫ turbulence model and Large Eddy Simulation (LES) with the Smagorinsky subgrid-scale model, are employed to study two-dimensional (2D) and …
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Analysis of ship performance in deep and shallow waters using CFD
… that it accounts for the action of viscosity and turbulence, and can therefore model scale effects and shallow water ship flows. However, with the rapid advent of computational methods in all fields of engineering, several areas have emerged as significant sources of ambiguity. Amongst these are …
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Mathematical modelling of flow and combustion in internal combustion engines
… herein addresses the problem of mathematical modelling of fluid flow and combustion in internal combustion engines. In particular, the investigation of three topics that constitute prime sources of uncertainty, in current numerical models, namely turbulence modelling, inaccuracies in the …
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Geometry-Aware Modeling of Rough-Wall Turbulence Using Reynolds-Averaged Navier-Stokes (RANS) Frameworks
… in Reynolds-Averaged Navier–Stokes (RANS) turbulence models remains fundamentally challenging. Classical approaches rely on hydrodynamic equivalence, typically through the equivalent sand-grain roughness height and empirical shifts of the logarithmic velocity profile, which can reproduce …
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