| Summary: | 碩士 === 國立臺灣海洋大學 === 系統工程暨造船學系 === 104 === The vortical flow generated around the sail and the body juncture of submarine is an important fluid mechanics problem. This thesis establishes a synchronous imaging system of flow visualization and time-resolved particle image velocimetry (TR-PIV) for studying the horse-shoe vortices (HSV) around a surface-mounted hydrofoil. The experiment is carried out in the 25 cm 25 cm test section of a water tunnel at a Reynolds number of about 9000.
Flow visualization results show six kinematic modes of HSV and their occurrence probabilities: steady (22%), amalgamating (12%), roll-up (4%), breakaway (27%), transition (15%) and random (20%). The probabilities of mode sequence pairs are noted: from steady to amalgamating is 12.2% as the highest; from amalgamating to steady and from transition to breakaway are 9.8% as the second highest.
The synchronous imaging onto the vertical plane right in front of the foil’s leading edge and the horizontal plane located around 1/2 chord length of the foil help depict the 3D kinematics of HSVs. It shows by checking the pattern of the particles’ paths that HSV is lifted while flowing downstream with the Wing-in-Ground effect. The data obtained using TR-PIV clearly show the varying trends of HSV’s position, size and strength with different kinematic modes.
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