Second Symposium on Turbulence and Shear Flow Phenomena
DOI: 10.1615/TSFP2
PARAMETRIC STUDY ON SUBOPTIMAL CONTROL FOR DRAG REDUCTION IN TURBULENT CHANNEL FLOW
pages 11-16
DOI: 10.1615/TSFP2.1650
SINOPSIS
A systematic analysis is made of suboptimal control for drag reduction. The influence of the amplitude of actuation (A) and the time scale of actuation (Δta+) is evaluated. Two wall sensing variables are employed (dω/dy|ω and (dp/dz|ω), with two actuations (∅2 and ∅3). It is found that the effect of A and Δta+ on the drag reduction rate (Dr) is significant. The near-wall behaviors of flow structure are analyzed to characterize the drag reduction. An optimal time scale is obtained at (Δta−) ~ 1.