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Direct Numerical Simulation of Turbulent Flow in a Square Duct: Analysis of Secondary Flows |
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| Authors: | Younghoon Joung Sung-Uk Choi Jung-Il Choi |
| Affiliation: | 1Researcher, Namwon Research Institute, Namwonkeonseol Engineering Co., Ltd., Gyeonggi-Do 431–060, Korea; formerly, Graduate Student, Dept. of Civil Engineering, Graduate School, Yonsei Univ., Seoul 120-749, Korea. E-mail: truss96@yonsei.ac.kr 2Professor, School of Civil and Environmental Engineering, Yonsei Univ., Seoul 120-749, Korea. E-mail: schoi@yonsei.ac.kr 3Research Associate, Dept. of Mechanical and Aerospace Engineering, North Carolina State Univ., E-mail: jchoi2@unity.ncsu.edu |
| Abstract: | A direct numerical simulation of turbulent flow in a square duct was performed for a Reynolds number based on bulk streamwise velocity and duct height equal to 4,440. The mechanism by which secondary flows are generated in a square duct was investigated. Two counterrotating secondary flows occur around the duct corner. These secondary flows were found to play a key role in momentum transfer between the corner and center of the duct. A conditional quadrant analysis was performed in the local maximum and minimum regions of the wall shear stress in order to characterize the pattern of the mean secondary flows. |
| Keywords: | Numerical models Simulation Secondary flow Reynolds number |