Abstract
Effect of apex angle 2α and rotated angle γ has been investigated on the behavior of the necklace vortex generated at the bottom front of a pyramid placed in a laminar boundary layer. Reynolds number based on the height of pyramid H is ReH≒610 and relative boundary layer thickness is δ/H=0.71, considering the symmetry, two typical conditions for γ are chosen, namely, γ = 0° and 45°. For the case of γ = 0°, bottom width D of the pyramids are 16.1mm and 60mm for 2α=30° and 90°, respectively. LDV was employed for velocity measurement. Distribution of spanwise vorticity can be understood by considering convection and production terms in vorticity transport equation .
