Characterization of coupling between inertial particles and turbulent wakes from porous disk generators

Abstract

This study presents the findings of a wind tunnel experiment investigating the behaviour of micrometric inertial particles with Stokes numbers around unity in the turbulent wake of a stationary porous disk. Various concentrations $\varPhi _{v}\in ([6-19] \times 10^{-6})$ of poly-disperse water droplets (average diameter 40–50 $\mathrm {\mu }$ m) are compared with sub-inertial tracer particles. Hot-wire anemometry, phase Doppler interferometry and particle image velocimetry were implemented in the near- and far-wake regions to study the complex dynamics of such particles. Quadrant analysis is used to explore the shear effects of the particle wake interaction. Turbulence statistics and particle size distributions reveal distinct differences in the structure of the wake when inertial particles are present in the flow. Additionally, there are different structures in the near and far wake regions and structures change with particle volume fraction.

The flow in the induction and entrance regions of lab‐scale wind farms

“…Thus, here porous disks will also be referred to as ADs. Single ADs have been used to study wake meandering, 6,7 the wake of a yawed turbine, 8 the effect of transient loads, 9 the effect of the boundary layer on the wake, 10 and, recently, the effect of inertial particles on the turbulent wake 11 . However, the major benefit comes when studying a wind farm with multiple turbines.…”

Aerodynamics of the square-back Ahmed body under rainfall conditions

“…This is a remarkable omission, as turbulent wakes charged with inertial particles (such as rainfall) have also important environmental and industrial applications. For instance, recent works have found that the presence of inertial (a) E-mail: martin.obligado@univ-grenoble-alpes.fr (corresponding author) particles can modify the structure and persistence of the turbulent wake of scaled wind turbines [12,13] and to affect the performance and aerodynamic stall of aircrafts [14].…”

“…It is worth noting that at higher injection rate, this asymmetry is less pronounced, probably because the switching process is almost annihilated. Another (potentially concomitant) explanation is related to the added mass transported within the recirculation bubble in the presence of rainy conditions [13,21]. This may lead to an increase in the energy barrier required for the switching process to be triggered.…”