平板壁上の直立正方形平板上流に形成する非定常首飾渦の可視化計測

抄録

It is well known that necklace vortices are formed in front of a three-dimensional object set on the ground wall. The necklace vortices may be related with various flow fields in mechanical engineering, aeronautical engineering, civil engineering and so on. However, the detail of the structure and the behavior of the necklace vortices for wide range of Reynolds number is not well known yet. For the high Reynolds number, the vortices become unsteady and complicated, and the property depends on various shape of the three-dimensional object. Therefore, in this investigation a thin square flat plate is employed as the basic and simple three-dimensional object. Then, the property of unsteady necklace vortices formed in front of a vertical square plate standing on a ground wall is investigated by using the visualization and PIV measurement with a water channel. As a result, the property of the unsteady necklace vortices is revealed. Necklace vortex pattern can be classified by only the Reynolds number, and does not depend on the boundary layer thickness.