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Biomedical subjects

A Vikhansky

Publications and source records attributed to A Vikhansky.

5 recordsLinked to original sources
PubMed2006

Coarse-grained simulation of chaotic mixing in laminar flows.

A model for chaotic mixing has been formulated and tested. The advection of a passive scalar by laminar flows with high Péclet numbers is modeled by a finite-volume method on a coarse grid. The scales which are smaller than the increment of the grid are modeled by an approximate subgrid model. The artificial diffusivity of the finite-difference method plays a twofold role. It prevents the formation of spurious oscillations of the solution and also models the transport of the variation of the scalar from the large to subgrid modes.

Journal Article↗
PubMed2004

Simulation of topological chaos in laminar flows.

In the present study the immersed boundary method is used for numerical simulation of Stokes-flow mixing driven by stirrers moving in a such way that trajectories of the stirrers form a "braid" in the augmented phase space. It is demonstrated that topologically more complex flow can be a more effective blender than its topologically simpler counterpart with the same energy dissipation rate. Positions of elliptic periodic points are detected and it is demonstrated that the total area of unmixed islands is negligible in comparison with the area of the cavity. Matrix representation of a mixing protocol provides a good estimation for the stretching rate.

Centrifugation↗
PubMed2000

Granular flow in a three-dimensional rotating container

We considered a flow of a cohesionless granular material in a partially filled three-dimensional rotating container. A model is suggested to describe a density of the surface flow and the profile of the free surface of the granular material. It is shown that when the container has an ellipsoidal shape the obtained system of partial differential equations can be reduced to a set of two ordinary differential equations.

Journal Article↗
PubMed1999

Mechanism of the onset of axial segregation in a rotating cylindrical drum filled with binary granular mixtures.

A phenomenon of axial band formation in a long rotating cylindrical drum filled with a binary granular mixture is described as a two-stage process. At the first stage, due to different mobility of the large and small particles, a central core occupied by a small-size fraction is formed along the axis of the drum. The axial segregation, i.e., transverse band formation, is found to be associated with the instability of the radially segregated state caused by an asymmetry of the free surface of the granular material. This instability is caused by the difference in the repose angles of two granular fractions and deviation of the filling level of the drum from 0.5.

Journal Article↗