1,721,001 research outputs found
On the formulation of an inverse problem and an optimization method for turbomachinery design,
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Hollow wakes past arbitrarily shaped obstacles
No full textAn analytical solution is presented for steady inviscid separated flows modelled by hollow vortices, that is, by closed vortex sheets bounding a region with fluid at rest. Steady flows past arbitrary obstacles protruding from an infinite wall are considered. The solution is similar to that of the vortex patch model; it depends on two free parameters that define the size of the hollow vortex and the location of the separation point. When a sharp edge constrains the separation point (Kutta condition), the solution depends on a single parameter. As with the vortex patch model, families of growing vortices exist, which represent the continuation of desingularized point vortices. Numerical results are presented for the flows past a semicircular bump, a Ringleb snow cornice and a normal flat plate. The differences from the previous results found in the literature are analysed and discussed with the present solutions for the flow past a normal flat plate. Key words
Integration of multi-fidelity methods in parametrized non-intrusive reduced order models for industrial applications
Full text linkExploring the behavior of complex industrial problems might become burdensome, especially in high-dimensional design spaces. Reduced Order Models (ROMs) aim to minimize the computational effort needed to study different design choices by exploiting already available data. In this work, we propose a methodology where the full-order solution is replaced with a Proper Orthogonal Decomposition based ROM, enhanced by a multi-fidelity surrogate model. Multi-fidelity approaches allow to exploit heterogeneous information sources, and consequently reduce the cost of creating the training data needed to build the ROM. To explore the multi-fidelity ROM capabilities, we present and discuss results and challenges for an automotive aerodynamic application, based on a geometric morphing of the DrivAer test case with multi-fidelity fluid-dynamics simulations
Analysis and low order modeling of the inhomogeneous transitional flow inside a T-mixer
No full textA direct numerical simulation of the transitional flow (Re=300 to Re=700) inside a T-mixer configuration has been carried out. Time records were collected and used to perform a proper orthogonal decomposition (POD) of the flow. Changes of the flow characteristics in the frequency spectra and extracted coherent spatial structures indicate flow transition across the investigated Reynolds numbers. The POD modes were used to derive a low-order model of the flow. An a priori test limits the possibilities of the modeling; for the periodic case it demonstrates that the flow can be reduced to a system of a few degrees of freedom, while for the turbulent ones this results to be extremely difficult because of the large number of degrees of freedom that are necessary to describe the flow
The effect of shocks on second order sensitivities for the quasi-one-dimensional Euler equations
No full textL. Muscarà, M. Cisternino, A. Ferrero, A. Iob, F. Larocca, K. Samouchos, H. Telib "Enhancing turbulence modeling with data-driven approaches: a focus on the field inversion and machine learning paradigm. "
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