Flying-Hot-Wire Study of 2-Dimensional Mean Flow Past an NACA 4412 Airfoil at Maximum Lift

Abstract

Hot-wire measurements have been made in the boundary layer, the separated region, and the near wake for flow past an NACA 4412 airfoil at maximum lift. The Reynolds number based on chord was about 1,500,000. Special care was taken to achieve a two-dimensional mean flow. The main instrumentation was a hot-wire probe mounted on the end of a rotating arm. An unexpected effect of rotor interference was identified and brought under control. A digital computer was used to control synchronized sampling at closely spaced points along the probe arc. Ensembles of data were obtained at several thousand locations in the flow field. The data include intermittency, two components of mean velocity, and twelve mean values for double, triple, and quadruple products of two velocity fluctuations. The data are available on punched cards in raw form and also after use of smoothing and interpolation routines to obtain values on a fine rectangular grid aligned with the airfoil chord.