787 research outputs found
Large eddy simulations of miscible Rayleigh-Taylor instability
No full textT.W. Mattner, D.I. Pullin & P.E. Dimotakishttp://www.damtp.cam.ac.uk/iwpctm9/proceedings/IWPCTM9/Papers/Mattner_Pullin_Dimotakis/Abstract.pd
How sensitive are Lagrangian coherent structures to uncertainties in data?
No full textLagrangian coherent structures (LCSs) are time-varying entities which capture the most influential transport features of a flow. These can for example identify groups of particles which have greatest stretching, or which maintain a coherent jet or vortical structure. While many different LCS methods have been developed, the impact of the inevitable measurement uncertainty in realistic Eulerian velocity data has not been studied in detail. This article systematically addresses whether LCS methods are self-consistent in their conclusions under such uncertainty for nine different methods: the finite time Lyapunov exponent, hyperbolic variational LCSs, Lagrangian averaged vorticity deviation, Lagrangian descriptors, stochastic sensitivity, the transfer operator, the dynamic Laplacian operator, fuzzy c-means clustering and coherent structure colouring. The investigations are performed for two different realistic data sets: a computational fluid dynamics simulation of a Kelvin–Helmholtz instability, and oceanographic data of the Gulf Stream region. Using statistics gleaned from stochastic simulations, it is shown that the methods which detect full-dimensional coherent flow regions are significantly more robust than methods which detect lower-dimensional flow barriers. Additional insights into which aspects of each method are self-consistent, and which are not, are provided.Aleksandar Badza, Trent W. Mattner, Sanjeeva Balasuriy
Artysta nowoczesny jako T.W.
No full textThe author analyses archival materials from IPN (Instytut Pamięci Narodowej – The Institute of National Remembrance) concerning a painter nicknamed ‘Tadeusz’. In 1973–1979, ‘Tadeusz’ was active as secret collaborator (t.w. – ”tajny współpracownik”) of SB (Służba Bezpieczeństwa – Interior Ministry Security Service). IPN documents contribute to the mapping of Polish art of the 1970s only to a limited extent. Nevertheless, they can form a basis for posing questions on artists’ collaborations with SB. The author claims that the acceptance of collaboration with SB was grounded in Tadeusz’s understanding of art based on the Enlightenment concept of modern art. He argues with a commonly accepted view that experimental art was persecuted in the Polish People’s Republic in the 1960s and the 1970s, and that the communist government showed any particular interest in fine art. In the annex, the author provides a full list of names found in Tadeusz’s files
Staggered grids for multidimensional multiscale modelling
No full textAvailable online 10 January 2024For high accuracy and to improve simulated wave characteristics, this article extends the concept of staggered grids to novel multidimensional multiscale modelling enabling efficient computation on sparse patches. Computational schemes for wave-like systems with small dissipation are often inaccurate and unstable due to truncation errors and numerical roundoff errors. Hence simulations of wave-like systems lacking proper handling of these numerical issues often fail to represent the physical characteristics of wave phenomena. This challenge gets even more intricate for multiscale modelling, especially in multiple dimensions. But numerical schemes on staggered grids are significantly less dispersive, better model the group velocity, and preserve much of the wave characteristics. This article develops and exhaustively studies all 167 040 possible 2D multiscale staggered grids. Our catalog (Divahar, 2023) interactively plots all of them. Only 120 multiscale staggered patch grids give stable and accurate multiscale schemes. Specifically, this article develops these 120 multiscale staggered grids and demonstrates their stability, accuracy, and wave-preserving characteristic for equation-free multiscale modelling of weakly damped linear waves. These characteristics of the developed multiscale staggered grids must also hold in general for multiscale modelling of many complex spatio-temporal physical phenomena such as the general computational fluid dynamics.J. Divahar, A.J. Roberts, Trent W. Mattner, J.E. Bunder, Ioannis G. Kevrekidi
[T.W Brown read-in with children and other black women authors]
No full textVideo footage from The Black Academy of Arts and Letters recorded during a library event with author T.W. Brown in February of 1989. The footage shows children seated in a library listening as she reads from a book in her hands. The event includes two other black women authors
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[T.W Brown read-in with children and other black women authors]
No full textVideo footage from The Black Academy of Arts and Letters recorded during a library event with author T.W. Brown in February of 1989. The footage shows children seated in a library listening as she reads from a book in her hands. The event includes two other black women authors
Large‐scale simulation of shallow water waves via computation only on small staggered patches
No full textA multiscale computational scheme is developed to use given small microscale simulations of complicated physical wave processes to empower macroscale system‐level predictions. By coupling small patches of simulations over unsimulated space, large savings in computational time are realizable. Here, we generalize the patch scheme to the case of wave systems on staggered grids in two‐dimensional (2D) space. Classic macroscale interpolation provides a generic coupling between patches that achieves consistency between the emergent macroscale simulation and the underlying microscale dynamics. Spectral analysis indicates that the resultant scheme empowers feasible computation of large macroscale simulations of wave systems even with complicated underlying physics. As an example of the scheme's application, we use it to simulate some simple scenarios of a given turbulent shallow water model.Judith E. Bunder, Jayaraman Divahar, Ioannis G. Kevrekidis, Trent W. Mattner, Anthony J. Robert
Plantagenets tragicall story [electronic resource] : or, The death of King Edward the Fourth: with the unnaturall voyage of Richard the Third, through the Red Sea of his nephews innocent bloud, to his usurped crowne. Metaphrased by T.W. Gent.
No full textT.W. = Thomas Wincoll. Sometimes attributed to Thomas Weaver.In verse.With an errata slip.The portrait of the author is signed: W.M. fecit., i.e. William Marshall.Annotation on Thomason copy: "Nou: 17".Reproduction of the original in the British Library.Wing (2nd ed.)ThomasonElectronic reproduction
T.W. Adorno e a psicologia social T.W. Adorno and social psychology
No full textNeste ensaio, ressalta-se a importância da disciplina Psicologia Social na obra de T. W. Adorno e a concepção que formula acerca dessa disciplina. Esse autor defende que há uma nova forma de configuração dos indivíduos, expressada por atitudes e comportamentos individuais padronizados e por um ego frágil, facilmente cooptado por movimentos sociais totalitários. Tais indivíduos surgem em uma sociedade caracterizada por uma forma de dominação calcada na racionalidade administrativa e tecnológica. Para esse autor, a Psicologia Social deveria estudar esse objeto para que, com o esclarecimento produzido e difundido, os indivíduos possam resistir à adesão cega a movimentos sociais irracionais, tal como o fascismo, insistindo que a determinação desses movimentos não é individual, mas social.In this assay, the importance of Social Psychology discipline in the T.W. Adorno's work and the specific conception that he formulates about it are pointed out. He defends that there is a new way of individuals' configuration, expressed by standardized attitudes and their own behaviors, such as a fragile ego, which is easily co-opted by totalitarian social movements. Such individuals appear in a society characterized by a form of domination based on administrative and technological rationality. For that author, Social Psychology would have to study this issue so that, with the enlightenment achieved and diffused, the individuals are able to resist to the blind adhesion in irrational social movements, such as the fascism. Adorno empathized that the determination of these movements is not individual, but social
Two novel families of multiscale staggered patch schemes efficiently simulate large-scale, weakly damped, linear waves
No full textLink to a related website: https://unpaywall.org/10.1016/j.cma.2023.116133, Open Access via UnpaywallMany multiscale wave systems exhibit macroscale emergent behaviour, for example, the fluid dynamics of floods and tsunamis. Resolving a large range of spatial scales typically requires prohibitively high computational costs. The small dissipation in wave systems poses a significant challenge to further developing multiscale modelling methods in multiple dimensions. This article develops and evaluates two families of equation-free multiscale methods on novel 2D staggered patch schemes, and demonstrates the power and utility of these multiscale schemes for weakly damped linear waves. A detailed study of sensitivity to numerical roundoff errors establishes the robustness of developed staggered patch schemes. Comprehensive eigenvalue analysis over a wide range of parameters establishes the stability, accuracy, and consistency of the multiscale schemes. Analysis of the computational complexity shows that the measured compute times of the multiscale schemes may be 100,000 times smaller than the compute time for the corresponding (same resolution) full-domain computation. This work provides the essential foundation for efficient large-scale simulation of challenging nonlinear multiscale waves.J. Divahar, A.J. Roberts, Trent W. Mattner, J.E. Bunder, Ioannis G. Kevrekidi
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