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...

Sedimentation of large particles in turbulent environments

The aim of the present study is to investigate the sedimentation of large non-colloidal spherical particles in both quiescent and turbulent environments. To this aim, Direct Numerical Simulations are performed using an Immersed Boundary Method to account for the dispersed phase. The solid volume fractions considered are in the range 0.5%-1.0%,...

Direct numerical simulations of turbulent flow through porous channels and ducts

Direct numerical simulations of the fully developed turbulent flow through a porous channel and duct are performed based on the spectral element code Nek5000. The volume-averaged Navier-Stokes (VANS) equations are implemented in order to describe the flow in the composite medium. The numerical simulations of the VANS equations are carried out at...

Linear stability of a liquid flow through a poroelastic channel

A liquid flow through a channel is studied based on the Orr-Sommerfeld eigenvalue problem, where the lower wall of the channel is occupied by the saturated poroelastic medium. The linear stability analysis is investigated in detail for arbitrary value of the wavenumber. The eigenvalues are computed numerically by using the Chebyshev spectral...

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...

Adapting Wind Resource Estimation for Airborne Wind Energy Converters

Systems integration: Condition for success. The case of Hammarsby, Sjöstad and Eva-Lanxmeer

Today, many new urban areas, such as cities, towns, villages, or districts, are being built worldwide and their completion requires the development of a number of infrastructures. Traditionally, these infrastructures are planned in parallel. However, increased environmental awareness is pushing cities to improve their environmental performance....

Use of explicit filtering, second-order scheme and SGS models in LES of turbulent flow

In large eddy simulations (LES) using low-order finite-difference-type methods, the numerical error can be large in comparison to the effect of the sub-grid scale (SGS) model. In this paper, we study two approaches to explicit filtering which can reduce the numerical error involved. In the first approach, the non-linear convection term of the...