induced velocity
downwash velocity

Conservation of mass relates the mass flow to the induced velocity.

One of the key difficulties lies in modelling the induced velocity on the rotor disk.

So, the induced velocity is inversely proportional to the power loading .

However the most common application multiplies induced velocity term by F in the momentum equations.

Therefore the induced velocity can be expressed as:

At the most basic level of approximation a uniform induced velocity on the disk is assumed:

Conservation of energy considers these parameters as well as the induced velocity at the rotor disk.

This should provide greater accuracy than VC1 in cases where the convecting field is weak compared to the self induced velocity of the vortex.

The induced velocity is:

Blade element theory is combined with momentum theory to alleviate some of the difficulties in calculating the induced velocities at the rotor.

Conservation of linear momentum relates the induced velocity downstream in the far wake field to the rotor thrust per unit of mass flow.

Under certain mathematical premises of the fluid, there can be extracted a mathematical connection between power, radius of the propeller, torque and induced velocity.

The airflow over the tail is assumed to be a steady uniform flow comprising the vector sum of the bird's velocity and the induced velocity generated by the wings.

The nonlinear visco-elastic properties of muscles interact with these perturbation induced velocity and length differences such that they counteract directly, as they happen, the effects upon the body of the perturbation.

For an actuator disk of area , with uniform induced velocity at the rotor disk, and with as the density of air, the mass flow rate through the disk area is:

Alternatively the variation of the induced velocity along the radius can be modeled by breaking the blade down into small annuli and applying the conservation of mass, momentum and energy to every annulus.

Because of this the blade element theory is often combined with the momentum theory to provide additional relationships necessary to describe the induced velocity on the rotor disk (for further details see Blade Element Momentum Theory).

If the blade element method is applied to helicopter rotors in forward flight it is necessary to consider the flapping motion of the blades as well as the longitudinal and lateral distribution of the induced velocity on the rotor disk.