A proof of concept experiment for reducing skin friction by using a micro-blowing technique

Abstract

A proof of concept experiment for reducing skin friction has been conducted in the Advanced Nozzle

Current state and prospects of researches on the control of turbulent boundary layer by air blowing

“…Hwang [60] succeeded in the control by air blowing and showed that at М 1 ¼ 0.3 and C b ¼6 Â 10 À 3 , the minimal C f was reached, and there was a trend of its growth at further growth of C b . It is important that the minimum position depends on the permeable surface quality.…”

“…Hwang [60] seems to be among those pioneers who realized the significance of some above mentioned geometrical parameters and started using permeable materials made by advanced methods for the blowing. He established that conventional porous materials utilized at early stages of researches, processed high roughness.…”

Review of research into the concept of the microblowing technique for turbulent skin friction reduction

“…The reduction in skin friction of PN2 is as high as 60% (i.e., Cf/C, = 0.4) with the highest blowing rate of 0.205 kglmz/sec at a Mach number of 0.3 while the maximum reduction is 30% at a Mach number of 0.7. This difference was originally thought to be due to a Reynolds number effect [23]. After supersonic tests were conducted in which the skin friction reduction was even more than 80% the data of these subsonic tests were revisited and the real reason was found for why the reduction was less for Mach 0.7 than for Mach 0.3.…”

“…The subject of this paper is the innovative skin friction reduction method called the MBT [20,23]. The MBT has been developed through tests conducted since 1995 in the Advanced Nozzle and Engine Components Test Facility [21] at the NASA Glenn Research Center.…”

Using synthetic jet generators in the systems of control of separated flows of turbomachines

“…В досліджені [18] встановлено механізм взаємодії зву-кової хвилі та течії, внаслідок чого, на початку зони зриву виникають власні нестійкі коливання зсувного потоку. Під дією звукової течії відбувається посилення даних коливань, що призводить до приєднання потоку по всій довжині профілю, а при вимкненні -знову виникає зрив [19].…”