DOI: 10.1615/TSFP7
VARIATION OF FRICTION DRAG VIA SPANWISE TRANSVERSAL SURFACE WAVES
ABSTRAKT
The introduction of spanwise velocity fluctuations is a promising technique to influence the near-wall turbulent flow field such that friction drag is reduced. The essential physical mechanisms which significantly reduce the drag, however, have not been completely understood, yet. It is the objective of this numerical study to improve the fundamental knowledge of the mechanisms involved. The investigation is based on numerical solutions of flows over spanwise traveling transversal surface waves which are applied to modify the near-wall flow field. Two actuation configurations are analyzed in detail and compared with an unactuated flat plate boundary layer simulation. The damping of the wall-normal vorticity fluctuations above the entire surface and the decrease of turbulence production are identified as the two key features for drag reduction.