23rd Congress of International Council of the Aeronautical Sciences, 8-13 September, 2002, Toronto, Canada
Paper ICAS 2002-2.10.1

EXPERIMENTAL STUDY OF CHARACTERISTICS OF MICRO-HOLE POROUS SKINS FOR TURBULENT SKIN FRICTION REDUCTION

D. P. Hwang
NASA Glenn Research Center, USA

Keywords: skin friction reduction, porous skin, micro-blowing

The characteristics of micro-hole porous skins for the turbulent skin friction reduction technology called the micro-blowing technique (MBT), were assessed experimentally at Mach number of 0.4 and blowing fractions from zero to 0.005. The objective of this study was to provide guidelines for the selection of porous plates for MBT. The hole angle, pattern, diameter, aspect ratio and porosity were the parameters considered for this study. The additional effort to angle and stagger the holes was experimentally determined to be unwarranted in terms of skin friction benefit; therefore, these parameters were systematically eliminated from the parametric study. The impact of the remaining three parameters was evaluated by fixing two parameters at the reference values while varying the third parameter. The best hole diameter Reynolds number was found to be around 400, with an optimum aspect ratio of about 6. The optimum porosity was not conclusively discerned because the range of porosities in the test plates considered was not great enough. However, the porosity was estimated to be about 15 percent or less.

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