Inscrição na biblioteca: Guest
TSFP DL Home Arquivos Comitê executivo

EFFECT OF SUCTION APPLIED THROUGH A PAIR OF POROUS WALL STRIPS, ON A TURBULENT BOUNDARY LAYER

Olanrewaju Oyewola
Discipline of Mechanical Engineering, The University of Newcastle NSW, 2308, Australia

Lyazid Djenidi
Discipline of Mechanical Engineering, University of Newcastle, Newcastle, 2308, NSW, AUSTRALIA

Robert Anthony Antonia
Discipline of Mechanical Engineering, University of Newcastle, Newcastle, 2308, NSW, AUSTRALIA

Resumo

Hot-wire measurements have been made in a turbulent boundary layer subjected to concentrated suction, applied through two porous wall strips. The results indicate that the use of a second strip increases the total skin friction reduction over one suction strip. The use of two strips extends the relaminarisation zone but also reduces the overshoot in the longitudinal and normal rms velocities. While the minimum rms occurs at x/δ0 = 3.0 (one strip) and x/δ0 = 12 (two strips), the reduction observed for the latter case is larger. The rather large streamwise distance over which the reduction of Cf occurs may reflect the effect suction has on the large-scale structures. The effect is enhanced with two strips because the second strip acts on a boundary layer whose Reynolds number has been reduced by the first strip and whose near-wall active motion has been seriously weakened.