Experimental investigation of the wake of a lifting wing with cut-in sinusoidal trailing edges

The wake behind a NACA0012 wing at incidence with cut-in sinusoidal trailing edges (TE) is experimentally investigated. A wing model with interchangeable trailing edges is used to study their impact on the wake properties. Both vertical and span-wise traverses of hot-wires are done at different downstream positions, to obtain the downstream evolution of statistical properties and to perform spectral analysis. Stereoscopic particle image velocimetry is used to study the flow structure in a span-wise/cross-stream plane. Span-wise inhomogeneity of the velocity deficit and of the wake width is observed and explained by the presence of a span-wise/cross-stream flow induced by the cut-in modifications. Spectral analysis shows a decrease of shedding intensity with shorter TE wavelength, with up to 57% reduction when compared to a straight blunt wing. Blunt sinusoidal TEs offer a reduction of span-wise correlation compared to the blunt straight one, which is mitigated when compared to an unmodified wing. A sharp cut-in design is also studied, that exhibits a more broad-band shedding spike at a lower frequency