20 сентября в 1515, в ауд. 341/1 состоится
заседание Пермского городского гидродинамического семинара №1523
The dynamics of semen as an active fluid
Франк Плюрабуэ (Franck Plouraboue), директор по исследованиям CNRS Института механики жидкости, (IMFT, UMR 5502), Тулуза, Франция
In this presentation we first present recent experimental analysis of collective dynamics of concentrated semen. Considering first the simple configuration of semen dynamics between two planes, we perform PIV analysis of the observed stochastic dynamics, and found several similarity with 2D turbulence, that we interpret as an effect of confinement.
Furthermore, when considering an annular confinement of the semen, we observe an ordered state associated with a spontaneous rotation of the fluid, that we found consistent with an alignment phase transition ordering. The second part of the talk will consider numerical simulations of more dilute regimes where a collective orientation order is also present.
20 сентября в 1700, в ауд. 341/1 состоится заседание Пермского городского гидродинамического семинара №1524
Flows in confined micro-channels and rough fractures
Франк Плюрабуэ (Franck Plouraboue), директор по исследованиям CNRS Института механики жидкости, (IMFT, UMR 5502), Тулуза, Франция
Confined flows in complex geometries are important in various area : micro-fluidic, geophysics, petroleum engineering, etc..
In this presentation, single phase and low capillary number two-phase flows confined between two rough surfaces are covered.
Investigating pore-scale first, given by a single saddle-node problem between two successive maxima of the aperture field, we derive an asymptotic pore network model, useful for the computation of permeability, either with direct computation or using Effective Medium Approximation (EMA). Geometrical percolation is thus analyzed for single-phase flow. For two-phase flow, we analyze the lubrication dynamic of thin film, leading to a ‘Bretherton-regime’
of drop generation into a pinched channel. This analysis also permit to derive a pore-scale rule for two-phase invasion percolation.
The methods proposed for fracture will, finally extended in 3D for core-scale permeability computation from 3D images.