Flow Over Delta Wing with Low Dorsal Fin-PIV Study

Abstract

A recent theoretical and experimental work done on the vortex flow over slender flatplate delta wing with low dorsal fin is reviewed, and a particle image velocimetry (PIV) study is conducted to further the investigation. The distributions of the vorticity component normal to the cross-flow planes show significant flow asymmetry and non-conicity over the wing-fin combination at a high angle of attack and enhance the validation of the theoretical prediction that adding a low dorsal fin to the wing may destabilize the symmetric and conical vortex pair. Ideals for further work are suggested. Nomenclature b = wing span c0 = wing root chord Cn = yawing-moment coefficient, yawing moment aboutZ-axis/q∞Sb hL = local height of dorsal fin K = Sychev similarity parameter, tan α/tan ǫ q∞ = free-stream dynamic pressure S = wing area s = local semi-span of wing U∞ = free-stream velocity v, w = cross-flow velocity components X, Y, Z = balance body axes, Fig. 4 x, y, z = body axes of the wing α = angle of attack ǫ = semi-apex angle of wing β = sideslip angle ωx = axial vorticity, ∂w/∂y ∂v/∂z