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Numerical study of separated cross‐flow near a two‐dimensional rough wall with narrow apertures and suction
Author(s) -
Mokamati Satya,
Olson James A.,
Gooding Robert W.
Publication year - 2010
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.20243
Subject(s) - suction , surface finish , pressure drop , materials science , vortex , streamlines, streaklines, and pathlines , surface roughness , hydraulic roughness , turbulence , flow (mathematics) , aperture (computer memory) , mechanics , optics , geometry , composite material , meteorology , physics , mathematics , structural engineering , engineering
The turbulent flow ( Re = 1.5 × 10 5 ) near a rough wall with narrow apertures has been numerically analysed to study the effect of the aperture geometry and wall suction on the flow characteristics. The aperture entry geometry is characterized by roughness height and roughness width. The roughness height is varied from 0.3 to 1.2 mm and roughness width is varied from 2.6 to 4.0 mm. The wall suction is characterized by slot velocity which is varied from 0.25 to 5 m/s. The flow characteristics in terms of fluid streamlines, flow resistance, wall pressure, and wall shear have been presented for several cases. The results show that the flow through the apertures is dominated by a separation vortex that covers the aperture. As roughness height increased (or slope of the roughness), the vortex size increased. With increasing wall suction, the vortex size decreased and moved towards the aperture opening. The flow resistance characterized by pressure drop across the aperture is significantly high for very low wall suction and it is increased with increasing roughness slope. At higher wall suction the slot velocity and roughness geometry has less influence on flow resistance. Wall pressure and skin friction coefficients are dependent on the ratio of roughness height to width.