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Bohnenn, Sylvie (author)Computational power is a challenge when it comes to the high-fidelity modeling of nuclear reactors. Detailed simulations of reactor physics involve complex calculations that require significant computing resources, which can be time-consuming and expensive. Reduced Order Modeling (ROM) allows for an approximation of a complex model by only...master thesis 2023
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Li, Mingwu (author), Jain, S. (author), Haller, George (author)Dynamical systems are often subject to algebraic constraints in conjunction with their governing ordinary differential equations. In particular, multibody systems are commonly subject to configuration constraints that define kinematic compatibility between the motion of different bodies. A full-scale numerical simulation of such constrained...journal article 2023
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Hendriksen, Luuk (author)Aerodynamic load determination through integration of the surface pressure distribution is limited in accuracy by the discrete number of measurements taken. Therefore, typically relatively large numbers of spatially distributed measurements are required which increase setup complexity, latency, cost and weight while requiring physical access in...master thesis 2022
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Machine Learning Based local Reduced Order Modeling for the prediction of Unsteady Aerodynamic LoadsCatalani, Giovanni (author)Advancements in aircraft performance require increasingly complex design processes and tools. Simulating the unsteady non-linear aerodynamic interaction between a maneuvering aircraft and the surrounding flowfield poses serious challenges. High-Fidelity Computational Fluid Dynamics (CFD) methods, based on the numerical solution of the Navier...master thesis 2022
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Klein, Robin (author)In this master thesis several novel DEIM formulations are proposed that enable the construction of non-linearly stable hyper-reduced order models (hROMs) of the incompressible Navier-Stokes equations. The hROMs have the same mass, momentum and energy conservation properties as the previously proposed ROM, but they do not suffer of prohibitively...master thesis 2022
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van den Broek, Erik (author)High-fidelity models are computationally intensive to work with in many-query applications, such as the design process of small modular reactors. A reduced order model of the high-fidelity model can still accurately determine the quantities of interest with only a fraction of the computational cost, and thus can potentially solve the...master thesis 2022
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Toledo Farrando, Oscar (author)Reduced-order models (ROMs) are commonly used to reduce the complexity of large-scale fluid dynamics problems. The main technique to obtain their basis is proper orthogonal decomposition (POD), where an energy-based basis is obtained. Such a basis is derived without considering the governing equations. Moreover, if the flow dynamics are not...master thesis 2022
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Bougrimov, Denis (author)Sensitivity analysis and uncertainty quantification of nuclear reactors requires many expensive high-fidelity simulations. To approximate the dynamics of such a time and parameter dependent system efficiently and effectively, reduced order modelling (ROM) is used. In previous research, a ROM was constructed which used a combination of proper...master thesis 2022
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Verhagen, Joris (author)Humans and other biological bipedal walkers are extraordinarily agile and robust. This is especially apparent when certain features of the environment are unknown such as unexpected downsteps (for example, suddenly walking off the side-walk or not expecting the last stair when descending). Humans can negotiate these downsteps ---both expected...master thesis 2022
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Sahu, Sidhartha (author)Vortex generators (VGs) are typically about two orders of magnitude smaller than their host component (such as an airplane wing). For this reason, conducting a fully-resolved RANS simulation to isolate their impact on the flow field is computationally expensive. This work presents a goal-oriented adjoint-based approach to model vortex generators...master thesis 2022
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van Biert, L. (author), Segovia Castillo, P. (author), Haseltalab, A. (author), Negenborn, R.R. (author)The maritime industry is actively exploring alternative fuels and drive train technology to reduce the emissions of hazardous air pollutants and greenhouse gases. High temperature solid oxide fuel cells (SOFCs) represent a promising technology to generate electric power on ships from a variety of renewable fuels with high efficiencies and no...journal article 2022
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Ferreira, Bernardo P. (author), Andrade Pires, F. M. (author), Bessa, M.A. (author)This article introduces adaptivity in Clustering-based Reduced Order Models (ACROMs). The strategy is demonstrated for a particular CROM called Self-Consistent Clustering Analysis (SCA), extending it into the Adaptive Self-Consistent Clustering Analysis (ASCA) method. This is shown to improve predictions of Representative Volume Elements ...journal article 2022
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Xiao, C. (author), Lin, H.X. (author), Leeuwenburgh, O. (author), Heemink, A.W. (author)History matching can play a key role in improving geological characterization and reducing the uncertainty of reservoir model predictions. Application of reservoir history matching is restricted by the huge computational cost by amongst others the many runs of the full model. Surrogate models with a reduced complexity are therefore used to...journal article 2022
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Millan Valbuena, Enrique (author)We present a reduced order model (ROM) for a one-dimensional nonlinear gas dynamics problem: the isentropic piston. The main body of the PDE, the geometrical definition of the mesh nodes, and the boundary conditions are parametrized. The full order model is obtained with a Galerkin finite element discretization, under the Arbitrary Lagrangian...master thesis 2021
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Bourier, Sébastien (author)Evaluation of aircraft performance for design, certification, and maintenance purposes requires aerodynamic knowledge for the entire flight envelope of an aircraft. Simplified models that relate geometric properties and flight conditions of an aircraft to its aerodynamic properties are simply not sufficient anymore, as non-linear aerodynamic...master thesis 2021
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Blom, Peter (author)Research into constructing reduced-order models (ROM) to reduce computational cost or to interpret complex datasets from numerical or experimental sources has steadily been gaining popularity over the past few years. Many methods currently exist to construct ROMs. The proper orthogonal decomposition (POD) is one of the most widely adopted...master thesis 2021
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Cegielski, Gustaw (author)Model order reduction (MOR) has been a field of active research in the past twenty years, more recently also in fluid dynamics. The main advantage of MOR is computational cost reduction, which, along with equally important accuracy, constitute main objective in the MOR community.<br/>A main ongoing issue is that data volumes in fluid flow...master thesis 2021
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Abbas, Omar (author)Placing wind turbines together is economically advantageous. It helps in decreasing the use of land or sea space, impact on the landscape and the cost of installation and maintenance. However, placing turbines together has a downside: the aerodynamics interaction caused by the wakes can negatively influence the total electrical power production...master thesis 2021
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Pilania, Yogesh Kumar (author)Extensive computational resources are required to solve large-scale nonlinear problems having a finite element mesh with a large number of degrees of freedom (DOFs). Model order reduction (MOR) is a technique used to reduce these DOFs, facilitating a faster solution with reasonable accuracy. This work proposes a method for constructing a finite...master thesis 2021
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Xiao, C. (author)In the community of petroleum engineering, the use of surrogate modelling techniques have recently gained more and more popularity to improve the efficiency of history matching. However, it is still not possible to fully utilize their potential in realistic applications. One of the challenges is to retain high accuracy while increasing the...doctoral thesis 2021