Pengurangan Hambatan Aliran Pada Piringan Berputar Terselubung Dengan Alur Spiral Halus
In the past several years, significant efforts have been made to develop passive techniques that result in a net reduction in a surface shear stress due to boundary-layer turbulence. One technique that demonstrated net surface drag reduction and has potential for practical hydrodynamics applications...
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| Format: | Article NonPeerReviewed |
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[Yogyakarta] : Universitas Gadjah Mada
2005
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| Online Access: | https://repository.ugm.ac.id/23311/ http://i-lib.ugm.ac.id/jurnal/download.php?dataId=6256 |
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| Institution: | Universitas Gadjah Mada |
| Summary: | In the past several years, significant efforts have been made to develop passive techniques that result in a net reduction in a surface shear stress due to boundary-layer turbulence. One technique that demonstrated net surface drag reduction and has potential for practical hydrodynamics applications for example in an impeller of a turbomachinery is the use of streamwise grooves or riblet surface modifications. Coincidence between the optimal groove geometry and the height and dimensions of the transversally oscillating strands is believed to have the effect of stretching and damping the oscillation and hence reducing the friction.
New type of drag reduction phenomena on an enclosed rotating disk was clarified experimentally in this study by means of the torque measurement device and the hot film anemometer. Test disk is made of the etching process of fine spiral grooves of a disk surface.
Experimental result showed that for the disks with 150 and 155 grooves the moment coefficient
in the turbulent region in the Reynolds number range of 4 x 104 Re 6 x 105 for the small axial
clearance 1 mm and in the transition region 3.3 x105 < Re < 4.0x105 for the large axial clearance 20 mm, were lower than those on the smooth disk. The maximum drag reduction ratio was obtained about 15 % in the small axial clearance case.
Keywords: Boundary Layer, Rotating Disk, Viscous Drag Reduction, Friction Moment, Micro Groove Surface |
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