DOI: 10.1615/TSFP9
DRAG REDUCTION EFFECT DUE TO FINITE PERMEABLE WALL IN TURBULENT CHANNEL FLOW
ABSTRAKT
A three-dimensional numerical simulation for
turbulent channel flow with permeable wall was carried
out to investigate the dependency of permeable wall
thickness on drag reduction. The permeability in the
porous media attached on the outer solid wall was
modelled with the Darcy-Forchheimer model, and the
thickness of permeable wall was parametrically changed
up to the ratio of 20% to the bulk fluid height. The
governing equations for incompressible fluid in the both
bulk fluid and permeable regions were discretized by the
finite volume method and solved by the PISO algorithm.
When the thickness of permeable wall was
comparable with that of the turbulent boundary layer, drag
was reduced and its reduction ratio reached up to about
10%. When the sweep and ejection near wall was properly
controlled due to the wall permeability, the vortex
structure was stabilized and its formation process was not
frequently repeated, therefore, turbulent drag reduction
was achieved.