From the momentum theory the induced flow can be calculated using the formula
Vi = √[ T / 2 ρ A ]
where
Vi Induced Flow Velocity [m s^-1]
T Thrust (approximately equal to weight in a hover). [N]
ρ Air Density [kg m^-3]
A Disc Area [m^2]
This is only an approximation, but is a good starting point for calculations involving the rotor system.
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