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Flow control of circular cylinder with a V-grooved micro-riblet film

Flow control of circular cylinder with a V-grooved micro-riblet film
Flow control of circular cylinder with a V-grooved micro-riblet film
Flow structure around a circular cylinder with a V-grooved micro-riblet is investigated experimentally. The results are compared with that of a smooth cylinder having the same diameter. A flexible V-shaped micro-riblet with peak-to-peak spacing of is made using a MEMS fabrication process of PDMS (Polydimethylsiloxane) replica. The flexible micro-riblet is attached on a circular cylinder with which grooves are aligned with the streamwise flow direction. Drag force acting on the cylinder is measured for Reynolds numbers based on a cylinder diameter in the range ReD=2.5×103–3.8×104. At , the V-grooved micro-riblet cylinder reduces drag coefficient by 7.6%, compared with a cylinder with smooth PDMS surface. However, it increases drag coefficient about 4.2% at . Flow field around the micro-riblet cylinder is measured by using a 2-frame PIV velocity field measurement technique. Several hundreds instantaneous velocity fields are ensemble-averaged to get the spatial distributions of turbulent statistics including turbulence intensities and turbulent kinetic energy. For the case of drag reduction at ReD=4.8×103, the vortex formation region behind the V-grooved MRF cylinder is reduced about 10%, compared with the smooth cylinder due to enhanced entrainment of ambient inviscid fluid into the wake region. In addition, the total number of secondary vortices located inside the near wake region is decreased about 20%.
flow control, micro-riblet, v-groove, drag reduction, piv, mems
0169-5983
246-266
Lee, Sang-Joon
1e90563f-653e-40aa-8c35-d6ed0ccbbef5
Lim, Hee-Chang
2de5166a-cd5a-40c7-a808-630bf0e3b96b
Han, Manhee
7c64821a-5006-4c06-8d53-f31cad2f9802
Lee, Seung S.
f845f1cc-02bc-4ce6-8424-ff534e93445e
Lee, Sang-Joon
1e90563f-653e-40aa-8c35-d6ed0ccbbef5
Lim, Hee-Chang
2de5166a-cd5a-40c7-a808-630bf0e3b96b
Han, Manhee
7c64821a-5006-4c06-8d53-f31cad2f9802
Lee, Seung S.
f845f1cc-02bc-4ce6-8424-ff534e93445e

Lee, Sang-Joon, Lim, Hee-Chang, Han, Manhee and Lee, Seung S. (2005) Flow control of circular cylinder with a V-grooved micro-riblet film. Fluid Dynamics Research, 37 (4), 246-266. (doi:10.1016/j.fluiddyn.2005.05.002).

Record type: Article

Abstract

Flow structure around a circular cylinder with a V-grooved micro-riblet is investigated experimentally. The results are compared with that of a smooth cylinder having the same diameter. A flexible V-shaped micro-riblet with peak-to-peak spacing of is made using a MEMS fabrication process of PDMS (Polydimethylsiloxane) replica. The flexible micro-riblet is attached on a circular cylinder with which grooves are aligned with the streamwise flow direction. Drag force acting on the cylinder is measured for Reynolds numbers based on a cylinder diameter in the range ReD=2.5×103–3.8×104. At , the V-grooved micro-riblet cylinder reduces drag coefficient by 7.6%, compared with a cylinder with smooth PDMS surface. However, it increases drag coefficient about 4.2% at . Flow field around the micro-riblet cylinder is measured by using a 2-frame PIV velocity field measurement technique. Several hundreds instantaneous velocity fields are ensemble-averaged to get the spatial distributions of turbulent statistics including turbulence intensities and turbulent kinetic energy. For the case of drag reduction at ReD=4.8×103, the vortex formation region behind the V-grooved MRF cylinder is reduced about 10%, compared with the smooth cylinder due to enhanced entrainment of ambient inviscid fluid into the wake region. In addition, the total number of secondary vortices located inside the near wake region is decreased about 20%.

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More information

Published date: 2005
Keywords: flow control, micro-riblet, v-groove, drag reduction, piv, mems

Identifiers

Local EPrints ID: 23497
URI: http://eprints.soton.ac.uk/id/eprint/23497
ISSN: 0169-5983
PURE UUID: 8dff72c3-c3a0-4bde-97ab-edbb1a034d83

Catalogue record

Date deposited: 10 Mar 2006
Last modified: 15 Mar 2024 06:47

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Contributors

Author: Sang-Joon Lee
Author: Hee-Chang Lim
Author: Manhee Han
Author: Seung S. Lee

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