Analysis of the Turbulent Boundary Layer and Skin-Friction Drag Reduction of a Flat Plate by using the Micro-Blowing Technique
H. N. Khaboshan1, E. Yousefi2, J. Svorcan3
1Young Researchers and Elites Club, Science and Research Branch, Tehran, Iran
2Imam Khomeini International University, Qazvin, Iran
3University of Belgrade, Belgrade, Serbia
Keywords: drag reduction, micro-blowing technique, active flow control, turbulent boundary layer, flat plate
Abstract
Numerical analyses of turbulent boundary layer parameters and skin-friction drag reduction on a flat plate under the effect of air micro-blowing with the use of the SST k-w turbulence model are performed. The macroscale characteristics of a huge number of microjets are simulated by using a microporous wall model (MPWM) incorporated into ANSYS FLUENT by user-defined functions. Numerical results obtained within the Mach number range M=0.2-0.5 (Reynolds number Re=2.88x106-7.20x106) confirm the experimental data of other researchers. Furthermore, a slight increase in the boundary layer thickness, displacement thickness, and momentum thickness, as well as a decrease in the velocity gradient and shear friction are well captured. In comparison to a simple flat plate, applying air micro-blowing reduces the skin-friction coefficient by 51% at the Mach number M=0.4 and blowing fraction of 0.008. Additionally, the skin-friction coefficient decreases as the blowing fraction and Mach number increase.
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