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Superdiffusion in random velocity fields
Physical Review Letters, 1990We discuss the superdiffusive motion of a random walk in a medium containing random velocity fields. For a two-dimensional layered medium with y-dependent random velocities in the x direction u(y), 〈${\mathit{x}}^{2}$(t)〉\ensuremath{\sim}${\mathit{t}}^{2\ensuremath{\nu}}$, with 2\ensuremath{\nu}=3/2, and with strong sample-to-sample fluctuations.
, Bouchaud +4 more
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A robust velocity field control
IEEE Transactions on Control Systems Technology, 2002This paper is devoted to velocity field control (VFC) of uncertain robotic manipulators. We propose a proportional-integral (PI)-type controller derived from modeling error compensation ideas and singular perturbation theory, that requires a minimum knowledge of the plant (i.e., constant estimate of the inertia matrix).
Ilse Cervantes +3 more
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Extended passive velocity field control with variable velocity fields for a kneed biped
Advanced Robotics, 2001In this paper, two aspects for task specification and control of biped walking robot, i.e. (i) realization of safe control against human beings and the outside environment by utilizing a passive velocity field controller (PVFC), and (ii) energy-effective gait design based on virtual passive dynamic walking, are studied and a new control method is ...
Masaki Yamakita, Fumihiko Asano
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Environment and Planning A: Economy and Space, 1970
The city is not an undifferentiated terrain and travel does not occur along straight-line paths at constant velocities. Variations in travel velocities at different locations bend the minimum time paths away from regions of high congestion. This paper discusses a transformation of the urban plane into a time surface on which distance corresponds to ...
S. Angel, G.M. Hyman
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The city is not an undifferentiated terrain and travel does not occur along straight-line paths at constant velocities. Variations in travel velocities at different locations bend the minimum time paths away from regions of high congestion. This paper discusses a transformation of the urban plane into a time surface on which distance corresponds to ...
S. Angel, G.M. Hyman
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Diffusion by a Random Velocity Field
The Physics of Fluids, 1970Single-particle diffusion in a multivariate-normal, incompressible, stationary, isotropic velocity field is calculated in two and three dimensions by computer simulation and by the direct-interaction approximation. The computer simulations are carried out by storing the velocity field as a set of Fourier components and synthesizing in physical space ...
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The supergranule velocity field
Solar Physics, 1980A study of supergranule motions confirms horizontal velocities with peak values of typically 0.36 km s−1 as observed in Fe i 8688 A. These show no significant variation with height over the range of formation of C i 9111, Fe i 8688, and Mg i 8806, but there is a substantial reduction to about one-half of this at the level of Ca ii 8542.
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Conditioned Simulations of Random Velocity Fields
Mathematical Geosciences, 2008zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Geraets, David +2 more
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On the Determination of a Velocity Field with Prescribed Vorticity
Journal of Computational Physics, 1998A method for the determination of three-dimensional velocity field with prescribed vorticity is proposed which is based on the Flanders integral in the theory of differential forms. The velocity field which fulfills the appropriate boundary conditions is then obtained by adding a suitable potential flow, which requires the solution of only one Poisson ...
Möhring, Leonhard, Möhring, Willi
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Stress and Velocity Fields in Soil Mechanics
Journal of Mathematics and Physics, 1954Abstract : Lines of discontinuity in the plastic stress field of a cohesive soil in a state of plane strain are discussed. The jump conditions on the stress and the restrictions on the velocity field in the neighborhood of the line are obtained. The theory is applied to the problems of uniform pressure on 1 face of a wedge (or earth dam) and to a ...
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2013
Inertia is known to play a significant role in the upper part of the respiratory tract. Additionally, an accurate description of the air velocity field in the branches can be useful in many situations, for example if one aims at investigating the deposition process of sprays.
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Inertia is known to play a significant role in the upper part of the respiratory tract. Additionally, an accurate description of the air velocity field in the branches can be useful in many situations, for example if one aims at investigating the deposition process of sprays.
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