| Title |
Development of High-Definition 3D-PTV andits Application to High-Precision Measurements of a Sphere Wake |
| Keywords |
Instantaneous 3D velocity field ; 순시 3차원 속도장 ; Sphere wake structures ; 구 후류 구조 ; Spatial turbulence properties ; 공간 난류 특성 ; GA based 3D-PTV ; 유전 알고리듬 기반의 3D-PTV |
| Abstract |
A Multi-Sectional 3D-PTV algorithm was developed to reduce the calculation time of the conventional GA-3D-PTV. The hardware system of the constructed 3D-PTV system consists of two high-speed cameras(1,024×1,018pixels, 60fps), a metal halogen lamp (400W) and a host computer. The sphere(D=30mm) is suspended in a circulating water channel(300mm×300mm×1,200mm) and Reynolds number is 1,130. About 5,000 instantaneous three-dimensional velocity vectors have been obtained by the constructed 3D-PTV system. Turbulent properties such as turbulent intensity, Reynolds stress and turbulent kinetic energy were obtained. An eigenvalue analysis was carried out using the obtained instantaneous 3D velocity vectors to get the topological relations of the asymptotically stable critical point. Two structured shells, inner shell and outer shell, were found in the sphere wake and their motions were clarified by the measured data. |