Control of base flows with micro jets
This paper presents the results of an experimental investigation carried out to control the base pressure in a suddenly expanded axi-symmetric passage. Active control in the form of micro jets was employed to control the base pressure. Air injection at four locations at the base, symmetric to t...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Walter de Gruyter
2011
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| Subjects: | |
| Online Access: | http://irep.iium.edu.my/46687/1/ijtkhan.pdf http://irep.iium.edu.my/46687/ http://www.degruyter.com/view/j/tjj.2011.28.issue-1/tjj.2011.009/tjj.2011.009.xml?format=INT |
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| Institution: | Universiti Islam Antarabangsa Malaysia |
| Language: | English |
| Summary: | This paper presents the results of an experimental
investigation carried out to control the base pressure in
a suddenly expanded axi-symmetric passage. Active control
in the form of micro jets was employed to control the
base pressure. Air injection at four locations at the base,
symmetric to the nozzle axis was used as the active control.
The jet Mach numbers at the entry to the suddenly
expanded duct studied were 1.87, 2.2 and 2.58. The area
ratio of the present study was 2.56. The length-to-diameter
ratio of the suddenly expanded duct varied from 10 to 1.
Nozzles generating the above jet Mach numbers were operated
with nozzle pressure ratio (NPR) in the range 3 to 11.
In addition to base pressure, wall pressure field along the
duct was also studied. It is found that the active control in
the form of blowing through small orifices (micro jets) are
effective in controlling the base pressure field. As high as
65 percent increase in base pressure was achieved for certain
combination of parameters of the present study. Micro
jets do not disturb the flow field in the enlarged duct. |
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