纵向涡对近壁湍流结构的影响

在封闭水槽中用氢气泡方法观察了纵向涡对近壁湍流结构的影响，涡的下洗侧出现了展向距离较宽、流动较稳定的快斑区，流向速度快；涡的上洗侧出现了含有慢斑的区域，流动结构复杂，流向速度慢，纵向涡使下洗侧速度较快的流体流向壁面，使上洗侧速度较慢的流体远离壁面。

EFFECT OF LONGITUDINAL VORIICES ON THE TURBULENT STRUCTURE IN NEAR-WALL REGION

The effect of longitudinal vortices on the turbulent structure of near-wall regionWas investigated with hydrogen bubble technique in a rectangular duct A wider high-speedstreak appears in the downwash region of vortex(where secondary flow is directed towardsthe wall),the flow is stable and the streamwise velocity is higher inside the streak)a regionincluding low-speed streaks is shown in the upwash part of vortex (where the secondaryflow is directed away from the wall),the flow structure is complicated and the strealnwisevelocity is lower.Due to the action of longitudinal vortices, the flow with higher velocityin the downwash region moves towards the wall,while the flow with lower velocity in theupwash region moves away from the wall.