6533b7cefe1ef96bd1257b6f

RESEARCH PRODUCT

Numerical study of two-dimensional wet foam over a range of shear rates

Topi Kähärä

subject

Fluid Flow and Transfer ProcessesMaterials scienceta114Computational Mechanicselastic deformation02 engineering and technology021001 nanoscience & nanotechnology01 natural sciencesShear rateSimple shearPhysics::Fluid DynamicsCondensed Matter::Soft Condensed MatterShear (geology)RheologyModeling and Simulationreologia0103 physical sciencesrheologyshear deformationComposite material010306 general physics0210 nano-technology

description

The shear rheology of two-dimensional foam is investigated over a range of shear rates with the numerical DySMaL model, which features dynamically deformable bubbles. It is found that at low shear rates, the rheological behavior of the system can be characterized by a yield stress power-law constitutive equation that is consistent with experimental findings and can be understood in terms of soft glassy rheology models. At low shear rates, the system rheology is also found to be subject to a scaling law involving the bubble size, the surface tension, and the viscosity of the carrier fluid. At high shear rates, the model produces a dynamic phase transition with a sudden change in the flow pattern, which is accompanied by a drop in the effective viscosity. This phase transition can be linked to rapid changes in the average bubble deformation and nematic order of the system. It is very likely that this phase transition is a result of the model dynamics and does not happen in actual foams. peerReviewed

http://urn.fi/URN:NBN:fi:jyu-201709143734