The 12th International Conference on Hydrodynamics
18 – 23 september 2016, Egmond aan Zee, The Netherlands
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THREE-DIMENSIONAL VELOCITY MEASUREMENT ON FREE SURFACE OF AIR-CORE INTAKE VORTEX UNDER CRITICAL SUBMERGENCE


Go-down ichd2016 Tracking Number 36

Presentation:
Session: Hydrodynamics in Ocean I
Room: Room 3
Session start: 10:30 Mon 19 Sep 2016

James Yang   james.yang@vattenfall.com
Affifliation: Department of Civil and Architectural Engineering, Royal Institute of Technology (KTH)

Chang Lin   chenglin@nchu.edu.tw
Affifliation: Department of Civil Engineering, National Chung Hsing University

Ming-Han Kuo   hankkuo414@gmail.com
Affifliation: Department of Civil Engineering, National Chung Hsing University

Ming-Jer Kao   d9362202@mail.nchu.edu.tw
Affifliation: Department of Civil Engineering, National Chung Hsing University

Chia-Feng Hu   g104062217@mail.nchu.edu.tw
Affifliation: Department of Civil Engineering, National Chung Hsing University

Vadoud Naderi   vadoudnaderi@yahoo.com
Affifliation: Water Science and Engineering Department, University of Tabriz


Topics: - Hydrodynamics in ocean, coastal and estuary engineering

Abstract:

THREE-DIMENSIONAL VELOCITY MEASUREMENT ON FREE SURFACE OF AIR-CORE INTAKE VORTEX UNDER CRITICAL SUBMERGENCE J. Yang Hydraulic Engineering, Department of Civil and Architectural Engineering Royal Institute of Technology (KTH), Stockholm 10044, Sweden james.yang@vattenfall.com C. Lin, M. H. Kuo, M. J. Kao, C. F. Hu Division of Hydraulic Engineering, Department of Civil Engineering National Chung Hsing University, Taichung, Taiwan chenglin@nchu.edu.tw, hankkuo414@gmail.com, d9362202@mail.nchu.edu.tw, g104062217@mail.nchu.edu.tw V. Naderi Water Science and Engineering Department, University of Tabriz, Tabriz, Iran vadoudnaderi@gmail.com (*corresponding author: chenglin@nchu.edu.tw) Abstract A three-dimensional velocity measurement on the free surface of strong air-core vortex over a bottom intake under the condition of critical submergence was performed in the test section of a re-circulating water channel, having the dimensions of 200.0 cm long, 100.0 cm wide and 40 cm high. A vertical pipe with an inner diameter of 9.4 cm was installed at the bottom of the test section (located 125.0 cm away from the inlet) and connected to a centrifugal pump, thus forming a bottom outlet intake system. The water depth of approaching and ambient flows was kept at 11.8 cm. The mean velocity of the approaching flow was controlled at 6.7 cm/s and the counterpart of pipe flow was adjusted to be 66.5 cm/s. A strongly rotating air-core vortex with critical submergence of 11.8 cm could be thus formed. A flow visualization technique with neutrally suspending polystyrene particles was used to visualize the formation and evolution of three-dimensional flow induced by the strong air-core vortex over the entrance of the bottom intake. Three high-speed digital cameras, one being mounted upon a 2-D carriage installed beneath the roof-slab and two located at both sides of water channel, were used to capture simultaneously three sets of images with a framing rate of 200 Hz. Under such a condition, the trajectory of each traced particle on the free-surface of rotational air-core vortex could be recorded simultaneously and analyzed precisely. The aim of this study is to obtain the three velocity components of the traced particles spirally moving right on the free surface of rotational air-core vortex in either Cartesian or Cylindrical coordinates, which were never reported in the literature.