Effect of Shroud Hole on the Force Characteristics of a Circular Cylinder
M.F. Osrin1, A.M. Azmi2, H.Yusoff3, N.A. Razak4

1M.F. Osrin, Faculty of Mechanical Engineering, University Teknologi MARA, Shah Alam, Selangor, Malaysia.
2A.M. Azmi*, Faculty of Mechanical Engineering, University Teknologi MARA, ShahAlam, Selangor, Malaysia.
3H. Yusoff, Faculty of Mechanical Engineering, University Teknologi MARA, Permatang Pauh, Pulau Pinang, Malaysia.
4N.A. Razak, School of Aerospace Engineering, University Sains Malaysia, Engineering Campus, Nibong Tebal, Pulau Pinang, Malaysia.
Manuscript received on September 09, 2019. | Revised Manuscript received on October 20, 2019. | Manuscript published on October 30, 2019. | PP: 5929-5935 | Volume-9 Issue-1, October 2019 | Retrieval Number: A3030109119/2019©BEIESP | DOI: 10.35940/ijeat.A3030.109119
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Abstract: Characteristics of flow pass a shrouded cylinder were investigated experimentally using uniform and non-uniform hole shrouds. The experiments were performed to compare the effect of hole-uniformity of the perforated shroud on the cylinder lift and drag. The porosity for uniform hole shrouds in triangular and square configurations were set around 0.30, while that for non-uniform hole shrouds were set from 0.25 to 0.37. The diameter ratio between the shroud and the bare cylinder was set at 2.0. The experiment was performed in a wind tunnel at Reynolds Number of 9.345 x 103 based on the bare cylinder diameter and constant incoming air flow speed. Results showed that although all shrouded cylinder models reduced drag significantly in comparison to that of the bare cylinder case, the non-uniform hole shrouds were considerably effective than the uniform hole shrouds. Total drag reduction achieved by the non-uniform hole shrouds of 30% porosity was between 90-95% whereas that of uniform hole was only 55-80% at the same porosity.
Keywords: Non-uniform hole, Perforated shroud, Vortex suppression, Vortex shedding.