6 research outputs found
Simulation of a particle-laden turbulent channel flow using an improved stochastic Lagrangian model
The purpose of this paper is to examine the Lagrangian stochastic modeling of
the fluid velocity seen by inertial particles in a nonhomogeneous turbulent
flow. A new Langevin-type model, compatible with the transport equation of the
drift velocity in the limits of low and high particle inertia, is derived. It
is also shown that some previously proposed stochastic models are not
compatible with this transport equation in the limit of high particle inertia.
The drift and diffusion parameters of these stochastic differential equations
are then estimated using direct numerical simulation (DNS) data. It is observed
that, contrary to the conventional modeling, they are highly space dependent
and anisotropic. To investigate the performance of the present stochastic
model, a comparison is made with DNS data as well as with two different
stochastic models. A good prediction of the first and second order statistical
moments of the particle and fluid seen velocities is obtained with the three
models considered. Even for some components of the triple particle velocity
correlations, an acceptable accordance is noticed. The performance of the three
different models mainly diverges for the particle concentration and the drift
velocity. The proposed model is seen to be the only one which succeeds in
predicting the good evolution of these latter statistical quantities for the
range of particle inertia studied
Numerical prediction of sediment deposition at a river confluence using an euler-lagrange method
International audienc
A new set of correlations of drag, lift and torque coefficients for non-spherical particles and large Reynolds numbers
International audienc
Improving the scavenging kernel of aerosol particles by small water drops
International audienc
Numerical Simulation and Modelling of the Forces Acting on Single and Multiple Non-Spherical Particles
The paper deals with gas-solid turbulent flows carrying non-spherical particles. The main objective of the present paper is to compute the hydrodynamics forces on non-spherical particles as a function of the particle orientation, for different particle shapes and a large range of particle Reynolds number. Two Direct Numerical Simulations at the scale of the particle are used, i.e. a body-fitted approach and a viscous penalty approach, in the case of a uniform flow with a single ellipsoidal particle. Results are compared with several correlations from the literature and a new proposal for the drag coefficient is given. The study is then extended to the case of a lattice of non-spherical particles to measure the pressure drop and to connect it with the drag coefficient