A comprehensive analysis of turbulent boundary layer at air blowing through a microperforated surface

A comprehensive experimental and numerical studies of the gradientless incompressible boundary layer modified by air blowing through a permeable (microperforated) wall was performed. Unlike the pioneering works of Hwang [3], the main objective of this work was to provide a detailed analysis of the boundary-layer characteristics over the permeable surface under the effect of blowing in order to make further improvements of the discussed boundary-layer control method possible. A consistent reduction of the local skin-friction coefficient over the permeable sample at various values of the blowing coefficient, reaching a maximum reduction of 70%, was shown. It was also established that air blowing can provide reduction of the plate total drag of about 4.5-5% even at comparatively low values of the blowing mass flow rate.