A rotor free-wake model including fuselage effects was estaolished to predict the rotor in?duced velocity flowfield of a real helicopter which has a combined rotor and fuselage configuration, and to provide a calculating method of the downwash flowfield for airborne rocket or missile fire. In this model, a rolled-up tip vortex model was used to simulate the effects of the wake on the flowfield, a second-order lifting-line model was adopted to represent the effects of the blade on the flowfield and a source panel model was included to take into account the induced and obstructed effects of the fuselage on the rotor wake. Based, upon the free-wake model, numerical examples for a 4-blade combined rotor and fuselage configuration of University of Maryland and a 2-blade combined rotor and fuselage config?uration of the Georgia Tech were given. The computations of steady and unsteady flow velocities were carried out. The comparison between calculated result and available experimental data shows the effec?tiveness of the method.
Key words
fluidal mechanics /
downwash /
helicopter /
rotor /
blade tip vortex /
free wake
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Footnotes
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