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NASA-TN-D-7163
Effects of fineness and closure ratios on boattail drag of circular-arc-afterbody models with jet exhaust at Mach numbers up to 1.3
Year: 1973
Abstract: The effects of variations in fineness ratio and closure ratio on the boattail drag of circular-arc afterbody models have been investigated at static conditions and at Mach numbers from 0.40 to 1.30. Angle of attack was varied from -4° to 8°. Jet total-pressure ratio was varied from jet off to about 6, depending on Mach number. Reynolds number based on model maximum diameter varied approximately from 1.20 × 106 to 2.18 × 106.
The results of this investigation indicate (1) that for configurations with the same closure ratio, increasing fineness ratio results in lower pressure drag and a higher drag-rise Mach number and (2) that for configurations with the same fineness ratio, increasing closure ratio generally results in lower pressure drag and an increased drag-rise Mach number. For all configurations at most subsonic Mach numbers, going from jet off to jet on generally had a greater effect on lowering pressure drag than did further increases in pressure ratio for the range of pressure ratios tested. Also, at subsonic speeds before the drag rise and at a scheduled jet total-pressure ratio, the total drag (pressure plus calculated skin friction) is approximately equal for configurations with the same closure ratio. Pressure axial force increased with increasing angle of attack tout pressure drag decreased.
The results of this investigation indicate (1) that for configurations with the same closure ratio, increasing fineness ratio results in lower pressure drag and a higher drag-rise Mach number and (2) that for configurations with the same fineness ratio, increasing closure ratio generally results in lower pressure drag and an increased drag-rise Mach number. For all configurations at most subsonic Mach numbers, going from jet off to jet on generally had a greater effect on lowering pressure drag than did further increases in pressure ratio for the range of pressure ratios tested. Also, at subsonic speeds before the drag rise and at a scheduled jet total-pressure ratio, the total drag (pressure plus calculated skin friction) is approximately equal for configurations with the same closure ratio. Pressure axial force increased with increasing angle of attack tout pressure drag decreased.
Subject: AERODYNAMIC
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| contributor author | NASA - National Aeronautics and Space Administration (NASA) | |
| date accessioned | 2017-09-04T18:37:15Z | |
| date available | 2017-09-04T18:37:15Z | |
| date copyright | 01/01/1973 | |
| date issued | 1973 | |
| identifier other | JMYKAEAAAAAAAAAA.pdf | |
| identifier uri | http://yse.yabesh.ir/std;query=authoCA5893FD081D49A96159DD6EFDEC014A/handle/yse/219124 | |
| description abstract | The effects of variations in fineness ratio and closure ratio on the boattail drag of circular-arc afterbody models have been investigated at static conditions and at Mach numbers from 0.40 to 1.30. Angle of attack was varied from -4° to 8°. Jet total-pressure ratio was varied from jet off to about 6, depending on Mach number. Reynolds number based on model maximum diameter varied approximately from 1.20 × 106 to 2.18 × 106. The results of this investigation indicate (1) that for configurations with the same closure ratio, increasing fineness ratio results in lower pressure drag and a higher drag-rise Mach number and (2) that for configurations with the same fineness ratio, increasing closure ratio generally results in lower pressure drag and an increased drag-rise Mach number. For all configurations at most subsonic Mach numbers, going from jet off to jet on generally had a greater effect on lowering pressure drag than did further increases in pressure ratio for the range of pressure ratios tested. Also, at subsonic speeds before the drag rise and at a scheduled jet total-pressure ratio, the total drag (pressure plus calculated skin friction) is approximately equal for configurations with the same closure ratio. Pressure axial force increased with increasing angle of attack tout pressure drag decreased. | |
| language | English | |
| title | NASA-TN-D-7163 | num |
| title | Effects of fineness and closure ratios on boattail drag of circular-arc-afterbody models with jet exhaust at Mach numbers up to 1.3 | en |
| type | standard | |
| page | 123 | |
| status | Active | |
| tree | NASA - National Aeronautics and Space Administration (NASA):;1973 | |
| contenttype | fulltext | |
| subject keywords | AERODYNAMIC | |
| subject keywords | AFTERBODIES | |
| subject keywords | ANGLE | |
| subject keywords | ATTACK | |
| subject keywords | BOATTAILS | |
| subject keywords | DRAG | |
| subject keywords | EXHAUST | |
| subject keywords | JET | |
| subject keywords | MACH | |
| subject keywords | NUMBER | |
| subject keywords | REYNOLDS |