61 research outputs found
Dopamine D1 receptor signalling in the lateral shell of the nucleus accumbens controls dietary fat intake in male rats
Travelling waves in pipe flow
A family of three-dimensional travelling waves for flow through a pipe of
circular cross section is identified. The travelling waves are dominated by
pairs of downstream vortices and streaks. They originate in saddle-node
bifurcations at Reynolds numbers as low as 1250. All states are immediately
unstable. Their dynamical significance is that they provide a skeleton for the
formation of a chaotic saddle that can explain the intermittent transition to
turbulence and the sensitive dependence on initial conditions in this shear
flow.Comment: 4 pages, 5 figure
Boundary-layer turbulence as a kangaroo process
A nonlocal mixing-length theory of turbulence transport by finite size eddies is developed by means of a novel evaluation of the Reynolds stress. The analysis involves the contruct of a sample path space and a stochastic closure hypothesis. The simplifying property of exhange (strong eddies) is satisfied by an analytical sampling rate model. A nonlinear scaling relation maps the path space onto the semi-infinite boundary layer. The underlying near-wall behavior of fluctuating velocities perfectly agrees with recent direct numerical simulations. The resulting integro-differential equation for the mixing of scalar densities represents fully developed boundary-layer turbulence as a nondiffusive (Kubo-Anderson or kangaroo) type of stochastic process. The model involves a scaling exponent (with → in the diffusion limit). For the (partly analytical) solution for the mean velocity profile, excellent agreement with the experimental data yields 0.58. © 1995 The American Physical Society
Simulation of wind gust structure in the atmospheric boundary layer with Lattice Boltzmann Method
Particle imaging velocimetry experiments and lattice-Boltzmann simulations on a single sphere settling under gravity
Inclusion of Preferential Diffusion in Simulations of Premixed Combustion of Hydrogen/Methane Mixtures with Flamelet Generated Manifolds
A Short Evaluation of a New Haematological Cell Counter — The Cell-Dyn 3000 - Following a Modified Tentative NCCLS-Procedure
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