Jose Soares de Andrade Jr.: Fluid flow localization in disordered systems

Описание: "Fluid flow localization in disordered systems"
January 10: In the first part of this talk, we will present results from computational simulations that reveal the role of inertial effects on fluid flow through disordered porous media. At sufficiently high Reynolds numbers, when inertia becomes relevant, we observe a transition from linear to non-linear behavior which is typical of experiments. We find that such a transition can be understood and statistically characterized in terms of the spatial distribution of kinetic energy in the system. More precisely, the flow at low Re is more “localized” due to channeling effects than the flow at high Re conditions. In the second part, by investigating the screening effects in flow through rough self-similar channels, we will disclose a surprising similarity between the distribution of hydrodynamic stress on their walls and the distribution of flux from a purely Laplacian field on the same geometry. Finally, from the results of Direct Numerical Simulations (DNS) of turbulent flows with non-Newtonian power-law fluids, we will show that the distributions of their vortex sizes remain invariant, regardless of the differences in rheology. This structural invariance is achieved through a self-organized mechanism at the microscopic scale of the turbulent motion that adjusts, according to the rheological properties of the fluid, the ratio between the viscous dissipations inside and outside the vortices. Moreover, shear-thickening fluids display a substantially more “localized” dissipation rate than shear-thinning fluids.

Lecture Slides for this Presentation are available at: https://z.umn.edu/Paris2019Slides
Question and Answer session (1:00:38)