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The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Mon, 20 Jan 2020 17:20:40 GMT2020-01-20T17:20:40ZModel-form and predictive uncertainty quantification in linear aeroelasticity
http://hdl.handle.net/10985/15562
Model-form and predictive uncertainty quantification in linear aeroelasticity
NITSCHKE, Christian T.; CINNELLA, Paola; LUCOR, Didier; CHASSAING, Jean-Camille
In this work, Bayesian techniques are employed to quantify model-form and predictive uncertainty in the linear behavior of an elastically mounted airfoil undergoing pitching and plunging motions. The Bayesian model averaging approach is used to construct an adjusted stochastic model from different model classes for time-harmonic incompressible flows. From a set of deterministic function approximations, we construct different stochastic models, whose uncertain coefficients are calibrated using Bayesian inference with regard to the critical flutter velocity. Results show substantial reductions in the predictive uncertainties of the critical flutter speed compared to non-calibrated stochastic simulations. In particular, it is shown that an efficient adjusted model can be derived by considering a possible bias in the random error term on the posterior predictive distributions of the flutter index.
Sun, 01 Jan 2017 00:00:00 GMThttp://hdl.handle.net/10985/155622017-01-01T00:00:00ZNITSCHKE, Christian T.CINNELLA, PaolaLUCOR, DidierCHASSAING, Jean-CamilleIn this work, Bayesian techniques are employed to quantify model-form and predictive uncertainty in the linear behavior of an elastically mounted airfoil undergoing pitching and plunging motions. The Bayesian model averaging approach is used to construct an adjusted stochastic model from different model classes for time-harmonic incompressible flows. From a set of deterministic function approximations, we construct different stochastic models, whose uncertain coefficients are calibrated using Bayesian inference with regard to the critical flutter velocity. Results show substantial reductions in the predictive uncertainties of the critical flutter speed compared to non-calibrated stochastic simulations. In particular, it is shown that an efficient adjusted model can be derived by considering a possible bias in the random error term on the posterior predictive distributions of the flutter index.New high-resolution-preserving sliding mesh techniques for higher-order finite volume schemes
http://hdl.handle.net/10985/17818
New high-resolution-preserving sliding mesh techniques for higher-order finite volume schemes
RAMÍREZ, Luis; FOULQUIÉ, Charles; NOGUEIRA, Xesús; KHELLADI, Sofiane; CHASSAING, Jean-Camille; COLOMINAS, Ignasi
This paper presents a new sliding mesh technique for the computation of unsteady viscous flows in the presence of rotating bodies. The compressible Euler and incompressible Navier–Stokes equations are solved using a higher-order (>2) finite volume method on unstructured grids. A sliding mesh approach is employed at the interface between computational grids in relative motion. In order to prevent loss of accuracy, two distinct families of higher-order sliding mesh interfaces are developed. These approaches fit naturally in a high-order finite volume framework. To this end, Moving Least Squares (MLS) approximants are used for the transmission of the information from one grid to another. A particular attention is paid for the study of the accuracy and conservation properties of the numerical scheme for static and rotating grids. The capabilities of the present solver to compute complex unsteady vortical flow motions created by rotating geometries are illustrated on a cross-flow configuration.
Thu, 01 Jan 2015 00:00:00 GMThttp://hdl.handle.net/10985/178182015-01-01T00:00:00ZRAMÍREZ, LuisFOULQUIÉ, CharlesNOGUEIRA, XesúsKHELLADI, SofianeCHASSAING, Jean-CamilleCOLOMINAS, IgnasiThis paper presents a new sliding mesh technique for the computation of unsteady viscous flows in the presence of rotating bodies. The compressible Euler and incompressible Navier–Stokes equations are solved using a higher-order (>2) finite volume method on unstructured grids. A sliding mesh approach is employed at the interface between computational grids in relative motion. In order to prevent loss of accuracy, two distinct families of higher-order sliding mesh interfaces are developed. These approaches fit naturally in a high-order finite volume framework. To this end, Moving Least Squares (MLS) approximants are used for the transmission of the information from one grid to another. A particular attention is paid for the study of the accuracy and conservation properties of the numerical scheme for static and rotating grids. The capabilities of the present solver to compute complex unsteady vortical flow motions created by rotating geometries are illustrated on a cross-flow configuration.