Three-dimensional viscoelastic instabilities in microchannels

Viscoelastic surface instabilities

We review three different types of viscoelastic surface instabilities: The Rayleigh – Plateau, the Saffman – Taylor and the Faraday instability. These instabilities are classical examples of hydrodynamic surface instabilities. The addition of a small amount of polymers to pure water can alter its flow behavior drastically and the type of instability may change not only quantitatively but also q...

Long-wavelength instabilities of three-dimensional patterns.

Long-wavelength instabilities of steady patterns, spatially periodic in three dimensions, are studied. All potentially stable patterns with the symmetries of the simple-, face-centered- and body-centered-cubic lattices are considered. The results generalize the well-known Eckhaus, zigzag, and skew-varicose instabilities to three-dimensional patterns and are applied to two-species reaction-diffu...

Instabilities of a three-dimensional localized spot.

We investigate the behavior of localized spots in three spatial dimensions in a model two-variable system describing the Belousov-Zhabotinsky reaction in water-in-oil microemulsion. We find three types of instabilities: splitting of a single spot (i) into two spots, (ii) into a torus, and (iii) into an unstable shell that splits almost immediately to six or eight new spots.

Three-Dimensional Fractal Geometry for Gas Permeation in Microchannels

The novel concept of a microfluidic chip with an integrated three-dimensional fractal geometry with nanopores, acting as a gas transport membrane, is presented. The method of engineering the 3D fractal structure is based on a combination of anisotropic etching of silicon and corner lithography. The permeation of oxygen and carbon dioxide through the fractal membrane is measured and validated th...

On-Chip Isotropic Microchannels for Cooling Three Dimensional Microprocessors