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Please use this identifier to cite or link to this item: http://repository.iitr.ac.in/handle/123456789/11504
Title: Experimental investigation of flow structure due to truncated prismatic rib turbulators using particle image velocimetry
Authors: Sharma N.
Tariq, Andallib
Mishra, Manish
Published in: Experimental Thermal and Fluid Science
Abstract: An experimental investigation of detailed flow field measurement in a rectangular duct with truncated prismatic ribs mounted on the bottom wall has been carried out using 2-dimensional particle image velocimetry (2-D PIV) technique. The truncated prismatic ribs have been manufactured by tapering the square rib from both the sides up to the center to provide rib height at the ends (h) of 0–8 mm with an increment of 2 mm. The PIV measurements have been performed in vertical as well as in horizontal streamwise planes for different Reynolds numbers and a fixed rib pitch to height ratio of 12. In addition, a number of PIV measurements in vertical symmetry plane have also been performed while covering the streamwise region of 46≤x/e≤120 to observe the nature of the flow in the test section and the flow periodicity. Overall, the emphasis is to investigate the flow structures and their dynamics in the inter-rib region in terms of time-averaged streamlines, mean velocities, vorticity fields, instantaneous velocity vector and corresponding vorticity fields, and fluctuation statistics in both the measurement planes. The close-up inspection based on critical point theory shows the significant evidence of salient critical points and limit cycles such as saddle point, stable and unstable node, bifurcation line and stable and unstable focus in both just upstream and downstream rib regions. The critical flow patterns around the rib confirm three-dimensionality and unsteady nature of the flow. The instantaneous flow characteristics reveal the presence of large-scale coherent vortices in the separated shear layer region, the existence of periodical processes such as intermittent ejection of the recirculation zone into the main flow and motion of the reattachment point. Significant reduction in the size of primary recirculation bubble and thereby reduction in reattachment length is observed for truncated prismatic ribs as compared to square rib in spanwise direction. © 2017 Elsevier Inc.
Citation: Experimental Thermal and Fluid Science (2018), 91(): 479-508
URI: https://doi.org/10.1016/j.expthermflusci.2017.11.004
http://repository.iitr.ac.in/handle/123456789/11504
Issue Date: 2018
Publisher: Elsevier Inc.
Keywords: Critical points
Passive flow control
PIV
Truncated prismatic rib
Turbulent statistics
Vortical structures
ISSN: 8941777
Author Scopus IDs: 57194590686
57119258700
55126794600
Author Affiliations: Sharma, N., Department of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee, Uttarakhand 247667, India
Tariq, A., Department of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee, Uttarakhand 247667, India
Mishra, M., Department of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee, Uttarakhand 247667, India
Funding Details: The author acknowledges the financial support of the Ministry of Human Resource and Development (MHRD), India for initiating this research activity in Mechanical & Industrial Engineering Department at Indian Institute of Technology Roorkee, India. Further authors wish to extend sincere thanks and acknowledge the support of Department of Science and Technology (DST), India for providing the financial assistance in order to improve the laboratories at IIT Roorkee under the FIST grant.
Corresponding Author: Tariq, A.; Department of Mechanical and Industrial Engineering, Indian Institute of TechnologyIndia; email: tariqfme@iitr.ac.in
Appears in Collections:Journal Publications [ME]

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