– We present an analysis of the statistical properties of hydrodynamic field fluctuations which reveal the existence of precursors to fingering processes. These precursors are found to exhibit power law distributions, and these power laws are shown to follow from spatial q-Gaussian structures which are solutions to the generalized non-linear diffusion equation. Over the past fifteen years, a no...

– We present an analysis of the statistical properties of hydrodynamic field fluctuations which reveal the existence of precursors to fingering processes. These precursors are found to exhibit power law distributions, and these power laws are shown to follow from spatial q-Gaussian structures which are solutions to the non-linear porous media equation. Over the past fifteen years, a nonextensiv...

A variational approach has been recently employed to determine the ideal time-dependent injection rate Q(t) that minimizes fingering formation when a fluid is injected in a Hele-Shaw cell filled with another fluid of much greater viscosity. However, such a calculation is approximate in nature, since it has been performed by assuming a high capillary number regime. In this work, we go one step f...

Viscous fingering of an air-nematic interface in a radial Hele-Shaw cell is studied when periodically switching on and off an electric field, which reorients the nematic and thus changes its viscosity, as well as the surface tension and its anisotropy (mainly enforced by a single groove in the cell). Undulations at the sides of the fingers are observed that correlate with the switching frequenc...

We present an experimental study of a new surfactant-driven fingering phenomenon in a Hele-Shaw cell. First, the threshold of instability is examined and compared with the linear theory. Second, the nonlinear evolution of fingering is quantified, and steady and unsteady patterns are distinguished. A wide range of dynamical behaviour is observed from drifting and merging fingers to cusp formatio...

This paper presents a signal processing technique for extracting the plucking point on a guitar string from an acoustically recorded signal. It also includes an original method for detecting the fingering point, based on the plucking point information.

Playing string instruments implies motor skills including asymmetrical interlimb coordination. How special is musical skill as compared to other bimanually coordinated, non-musical skillful performances? We succeeded for the first time to measure quantitatively bimanual coordination in violinists playing repeatedly a simple tone sequence. A motion analysis system was used to record finger and b...

Direct numerical simulations (DNS) of a shear layer with salt-fingering-favorable stratification have been performed for different Richardson numbers Ri and density ratios Rr. In the absence of shear (Ri 5 ‘), the primary instability is square planform salt fingering, alternating cells of rising and sinking fluid. In the presence of shear, salt fingering takes the form of salt sheets, planar re...

Mixing of two fluids in viscously unstable displacements is far from being fully understood. It is not known how mixing efficiency depends on the viscosity contrast between the fluids, especially for adevction-dominated flows (Peclet number Pe > 103). It is well known that when a less viscous fluid displaces a more viscous fluid, the displacement front is unstable and leads to the formation of ...

in this research the experimental and theoretical studies on different enhanced oil recovery (eor) techniques, i.e. water flooding (wf), gas injection (gi) and water alternating gas process (wag) were performed on specimens taken from an iranian carbonate offshore reservoir at the reservoir condition. the experimental results for each specified techniques were compared with the corresponding re...