Frequency dependence of drag reduction in a wavy surface turbulent boundary layer

Abstract eng:
Drag reduction effects by spanwise traveling surface waves with wall deformation in a fully turbulent flat plate boundary layer are investigated by PIV and u—PTV. A parametric study is performed in a low speed wind tunnel by varying the wave frequency, the amplitude, and the Reynolds number. Several parameters, e. g., wave amplitude, frequency, and Reynolds number are found to be relevant factors of the drag reduction effect. In this study, we focus on the wave frequency dependence of the drag reduction. Within the range of the parameters investigated, the maximum drag reduction ratio is 3.4 % at A+ = 9 and 1* 2110. Furthermore, the turbulence statistics above the moving surface are investigated in detail and the drag reduction mechanism is related to a damping of the turbulent flow structures with the induced spanwise velocity component.

• Export as: BibTeX | MARC | MARCXML | DC | EndNote | NLM | RefWorks
• Add to your basket