Wind tunnel test of stall regulation by blowing air through the leading edge

摘要

The stall of an aircraft is often asymmetrical left to right. By trigging stall on a non-stalled wing it could be possible to realize a symmetrization of the stall. In wind power turbines stall is used for regulation of the maximum power of the turbine at high wind speeds. Therefore it is desirable to be able to control the stalling properties. A wing profile has been tested with the purpose of investigating if it is possible, in an easy manner, to trigger/develop stall, or at a given angle of attack, decrease C(sub L) and decrease nose suction. The wing profile was tested in two-dimensional wind tunnel tests. The nose of the wing profile was perforated at the leading edge with a row of holes. The purpose of the tests was to investigate if it was possible to trigger/develop stall by blowing out air through the holes in the leading edge. The dynamic pressure of the wind tunnel free stream would principally be enough to give the desired results. After a modification of the laboratory equipment it was found that the stall clearly could be affected and regulated by compressor blowing air through the holes in the leading edge. The wing profile was asymmetric and tests between (alpha)=-30 degrees and (alpha)=+30 degrees gave information about two different types of geometries near the wing leading edge. (ERA citation 19:032978)