PIV investigation on a controlled backward facing step flow

Digital particle image velocimetry technique has been applied to the study of a passive control method for separated flows downstream a backward facing step (BFS). The method consists in substituting the solid wall downstream the step, in the separated region, by a permeable surface under which lays a sealed plenum. An almost complete damping of the low frequency fluctuation typical of the BFS flows including detected spanwise oscillations has been observed. The measurement technique allowed to provide an explanation for the controlled flow behavior