139,950 research outputs found
Machine Learning for Fluid Mechanics
The field of fluid mechanics is rapidly advancing, driven by unprecedented
volumes of data from field measurements, experiments and large-scale
simulations at multiple spatiotemporal scales. Machine learning offers a wealth
of techniques to extract information from data that could be translated into
knowledge about the underlying fluid mechanics. Moreover, machine learning
algorithms can augment domain knowledge and automate tasks related to flow
control and optimization. This article presents an overview of past history,
current developments, and emerging opportunities of machine learning for fluid
mechanics. It outlines fundamental machine learning methodologies and discusses
their uses for understanding, modeling, optimizing, and controlling fluid
flows. The strengths and limitations of these methods are addressed from the
perspective of scientific inquiry that considers data as an inherent part of
modeling, experimentation, and simulation. Machine learning provides a powerful
information processing framework that can enrich, and possibly even transform,
current lines of fluid mechanics research and industrial applications.Comment: To appear in the Annual Reviews of Fluid Mechanics, 202
Teaching Fluid Mechanics for Undergraduate Students in Applied Industrial Biology: from Theory to Atypical Experiments
EBI is a further education establishment which provides education in applied
industrial biology at level of MSc engineering degree. Fluid mechanics at EBI
was considered by students as difficult who seemed somewhat unmotivated. In
order to motivate them, we applied a new play-based pedagogy. Students were
asked to draw inspiration from everyday life situations to find applications of
fluid mechanics and to do experiments to verify and validate some theoretical
results obtained in course. In this paper, we present an innovative
teaching/learning pedagogy which includes the concept of learning through play
and its implications in fluid mechanics for engineering. Examples of atypical
experiments in fluid mechanics made by students are presented. Based on
teaching evaluation by students, it is possible to know how students feel the
course. The effectiveness of this approach to motivate students is presented
through an analysis of students' teaching assessment. Learning through play
proved a great success in fluid mechanics where course evaluations increased
substantially. Fluid mechanics has been progressively perceived as interesting,
useful, pleasant and easy to assimilate. It is shown that this pedagogy which
includes educational gaming presents benefits for students. These experiments
seem therefore to be a very effective tool for improving teaching/learning
activities in higher education
Relativistic viscoelastic fluid mechanics
A detailed study is carried out for the relativistic theory of
viscoelasticity which was recently constructed on the basis of Onsager's linear
nonequilibrium thermodynamics. After rederiving the theory using a local
argument with the entropy current, we show that this theory universally reduces
to the standard relativistic Navier-Stokes fluid mechanics in the long time
limit. Since effects of elasticity are taken into account, the dynamics at
short time scales is modified from that given by the Navier-Stokes equations,
so that acausal problems intrinsic to relativistic Navier-Stokes fluids are
significantly remedied. We in particular show that the wave equations for the
propagation of disturbance around a hydrostatic equilibrium in Minkowski
spacetime become symmetric hyperbolic for some range of parameters, so that the
model is free of acausality problems. This observation suggests that the
relativistic viscoelastic model with such parameters can be regarded as a
causal completion of relativistic Navier-Stokes fluid mechanics. By adjusting
parameters to various values, this theory can treat a wide variety of materials
including elastic materials, Maxwell materials, Kelvin-Voigt materials, and (a
nonlinearly generalized version of) simplified Israel-Stewart fluids, and thus
we expect the theory to be the most universal description of single-component
relativistic continuum materials. We also show that the presence of strains and
the corresponding change in temperature are naturally unified through the
Tolman law in a generally covariant description of continuum mechanics.Comment: 52pages, 11figures; v2: minor corrections; v3: minor corrections, to
appear in Physical Review E; v4: minor change
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