Ninth International Symposium on Turbulence and Shear Flow Phenomena
DOI: 10.1615/TSFP9
PRELIMINARY ANALYSIS OF PERMEABLE COATINGS FOR TURBULENT DRAG REDUCTION
pages 517-522
DOI: 10.1615/TSFP9.870
RÉSUMÉ
This study focuses on permeable coatings as a form of passive flow control. A simplified model is proposed to analyse the qualitative effect of the coating's thickness and permeability on drag reduction. For small permeability, the reduction is linear with the length scale of the streamwise permeability. For larger permeability, a degradation mechanism is investigated that depends critically on the geometric mean of the streamwise and wall-normal permeabilities. For a streamwise-to-wall-normal permeability ratio of order 10-100 the maximum drag reduction is predicted to be 15-25%.