Mechanics of dense suspensions in turbulent channel flows

Dense suspensions are usually investigated in the laminar limit where inertial effects are insignificant. When the flow rate is high enough, i.e. at high Reynolds number, the flow may become turbulent and the interaction between solid and liquid phases modifies the turbulence we know in single-phase fluids. In the present work, we study...

Structure and dynamics of turbulent flows over highly permeable walls

Highly porous materials are found in various industrial applications and environmental flows. In previous studies it was found that a turbulent flow along a highly porous wall experiences a higher skin friction as compared to a solid wall with similar surface roughness when the so-called permeability Reynolds number (Re_K) is larger than O(1)....

Direct numerical simulations of drag reduction in turbulent channel flow over bio-inspired herringbone riblet-texture

The use of drag reducing surface textures is a promising passive method to reduce fuel consumption. Probably most wellknown is the utilisation of shark-skin inspired ridges or riblets parallel to the mean flow. They can reduce drag up to 10%. Recently another bio-inspired texture based on bird flight feather riblets has been proposed. It differs...

Flow regimes of inertial suspensions of finite size particles

Inertial regimes in a channel flow of suspension of finite-size neutrally buoyant particles are studied for a wide range of Reynolds numbers: $500 \le Re\le 5000$, and particle volume fractions: $0 \le \Phi \le 0.3$. The flow is classified in three different regimes according to the phase-averaged stress budget across the channel \cite...

Particle Sedimentation in Wall-Bounded Turbulent Flows

In this work, a comparison between the results of point-particle direct numerical simulations and PIV/PTV experiments of a particle-laden horizontal channel flow is presented. The numerical simulations were preformed trying to mimic as much as possible the experimental conditions. The accuracy of the point-particle approach was evaluated by...

An Immersed Boundary Method for flows around rectangular objects

A second-order accurate and highly efficient Immersed Boundary Method (IBM) is presented for simulating flows along rectangular non-moving solid objects. In this method a rectangular object is placed on a staggered Cartesian grid such that its boundary coincides with grid points for the boundary-normal velocity component. By imposing forces at...