Asymmetric Vortex Flow Over Circular Cones
ROYAL AEROSPACE ESTABLISHMENT FARNBOROUGH (UNITED KINGDOM)
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Asymmetric vortex flow over circular cones is discussed in the light of predictions of the single-line-vortex model and of measurements made by Fiddes, Moir and Lean in the RAE 5m Wind Tunnel. For the case of separation lines specified as laterally symmetric, the space of conical solutions which contains the symmetric solutions of Bryson is explored thoroughly. No more than one pair of asymmetric solutions is found for each combination of a separation position and a ratio of incidence to cone semi-angle, except in a small region of the parameter space. The stability of the solutions to small asymmetric spatial disturbances is calculated. It emerges there is nowhere more than one stable solution, symmetric at smaller incidences, asymmetric at larger. In contrast, the experiment, on a 10 deg semi-angle cone, with laminar separation, reveals many different levels of local side force, depending on roll angle, lengthwise station, and unit Reynolds number, as well as incidence. It is shown that the flow can be highly non-conical. At 35 deg incidence the flow may be developing streamwise towards a conical state, but this is not apparent at 30 deg.
- Fluid Mechanics