Dynamics of prolate ellipsoidal particles in a turbulent channel flow

The dynamical behavior of tiny elongated particles in a directly simulated turbulent flow field is investigated. The ellipsoidal particles are affected both by inertia and hydrodynamic forces and torques. The time evolution of the particle orientation and translational and rotational motions in a statistically steady channel flow is obtained for...

The stress generated by non-Brownian fibers in turbulent channel flow simulations

Turbulent fiber suspension channel flow is studied using direct numerical simulation. The effect of the fibers on the fluid mechanics is governed by a stress tensor, involving the distribution of fiber position and orientation. Properties of this function in channel flow are studied by computing the trajectories and orientations of individual...

Particle spin in a turbulent shear flow

The translational and rotational motions of small spherical particles dilutely suspended in a turbulent channel flow have been investigated. Three different particle classes were studied in an Eulerian-Lagrangian framework to examine the effect of the response times on the particle statistics. The results for the fluctuating particle velocities...

On the performance of the moment approximation for the numerical computation of fiber stress in turbulent channel flow

Fiber-induced drag reduction can be studied in great detail by means of direct numerical simulation [ J. S. Paschkewitz et al., J. Fluid Mech. 518, 281 (2004) ]. To account for the effect of the fibers, the Navier-Stokes equations are supplemented by the fiber stress tensor, which depends on the distribution function of fiber orientation angles....

Direct numerical simulations of turbulent flow over a permeable wall using a direct and a continuum approach

A direct numerical simulation (DNS) has been performed of turbulent channel flow over a three-dimensional Cartesian grid of 30×20×9 cubes in, respectively, the streamwise, spanwise, and wall-normal direction. The grid of cubes mimics a permeable wall with a porosity of 0.875. The flow field is resolved with 600×400×400 mesh points. To enforce...