Particle acceleration in turbulent flows can be considered a key issue for many environmental and industrial applications e.g. cloud formation, atmospheric transport, combustion systems etc. It is thus, important to understand the nature of the acceleration since it affects the collision rate, the dispersion of droplets or particles in the carrier fluid. Many experimental and numerical studies on particle acceleration can be found in literature, but most of them deal with homogeneous and isotropic turbulence rather than wall-bounded flows which represent the objective of the present work. Previous studies focus mainly on the effect of inertia on particle acceleration, the relationship between acceleration and fluid coherent structures and the coupling between sampling and filtering mechanisms exerted by the particles on the fluid. Recent experiments in a turbulent boundary layer (Gerashchenko et al. 2008) revealed surprising trends for inertial particle accelerations in the nearwall region. In particular, acceleration variance was seen to increase with increasing inertia, contrary to what is found in isotropic turbulence (see Ayyalasomayajula et al. 2008, Bec et al. 2006 among others).
Direct Numerical Simulation of inertial particle accelerations in near-wall turbulence: effect of gravity
Soldati A.
2009-01-01
Abstract
Particle acceleration in turbulent flows can be considered a key issue for many environmental and industrial applications e.g. cloud formation, atmospheric transport, combustion systems etc. It is thus, important to understand the nature of the acceleration since it affects the collision rate, the dispersion of droplets or particles in the carrier fluid. Many experimental and numerical studies on particle acceleration can be found in literature, but most of them deal with homogeneous and isotropic turbulence rather than wall-bounded flows which represent the objective of the present work. Previous studies focus mainly on the effect of inertia on particle acceleration, the relationship between acceleration and fluid coherent structures and the coupling between sampling and filtering mechanisms exerted by the particles on the fluid. Recent experiments in a turbulent boundary layer (Gerashchenko et al. 2008) revealed surprising trends for inertial particle accelerations in the nearwall region. In particular, acceleration variance was seen to increase with increasing inertia, contrary to what is found in isotropic turbulence (see Ayyalasomayajula et al. 2008, Bec et al. 2006 among others).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
