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modeling forest fire by a paper-burning experiment: a realization of the interface growth mechanism,
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Jun Zhang, Y.-C. Zhang, P. Alstrom and M. T. Levinsen
Physica A, 189, 383 (1992)

Abstract:
We present an experiment on the propagation front of a flameless fire on a thin piece of paper. We find that fire fronts on a piece of paper follow quite well self-affine scaling statistics, with the roughening exponent \chi around 0,70, well above the value 1/2 in the theoretical interface growth model using Gaussian noise. This discrepancy may be due to an anomalously singular behavior of the noise distribution, consistent with some recent studies.


stochastic transition intermittency in pipe flows: experiment and model,
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Jun Zhang, D. Stassinopoulos, P. Alstrom and M. T. Levinsen
Physics of fluids, 6, 1722 (1994)

Abstract:
New experimental results at the onset of turbulence in a gravity-driven pipe flow are presented, and a simple phenomenological model is introduced to describe the intermittent behavior observed. In this model slugs are stochastically produced at the pipe inlet, the the decrease in velocity due to tuebulent friction is taken into account. The present approach shows that stochastic arguments accounts well for several experimental observations at low intermittency factors. In particular, it is shown that special intermittency routes to chaos are not needed to explain the exponentially decaying inverse cumulative distribution of laminar times.


periodic states in intermittent pipe flows: experiment and model,
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D. Stassinopoulos, J. Zhang, P. Alstrom and M. T. Levinsen
Physical Review E, 50, 1189 (1994)

Abstract:
We report an experimental study of a transition to periodic intermittency in pressure-driven pipe flows. The transition is preceded by a rapid increase of the intermittency factor with pressure. To model intermittent pressure-driven flows, we introduce a general model, where a fifth-order Ginzburg-Landau equation is coupled with a pressure-velocity relation that takes into account the frictional effect of the turbulence on the flow velocity. We determine the phase diagram and show that the model gives a qualitative understanding of the transition to periodic intermittency.

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