Speaker
Dr
L Zhao
(Norwegian University of Science and Technology)
Description
Turbulence modulations and transfer of mechanical energy
between solid spherical particles and a Newtonian carrier fluid has
been explored in two-way coupled direct numerical simulations in
a turbulent channel flow. At sufficiently large particle response
times the Reynolds shear stress and the turbulence intensities in
the spanwise
and wall-normal directions were attenuated whereas the velocity
fluctuations were augmented in the streamwise direction. The
physical mechanisms involved in the particle–fluid interactions
were analysed in detail, and it was observed that the fluid
transferred energy to the particles in the core region of the
channel whereas the fluid received kinetic energy from the
particles in the wall region. A local imbalance in the work
performed by the particles on the fluid and the work exerted by
the fluid on the particles was observed. This imbalance gave rise
to a particle induced energy dissipation which represents a loss of
mechanical energy from the fluid–particle suspension.
Additionally Reynolds budgets stresses are analyzed and
compared with the particle-unladen flow.
