By using the absolute transit times both the averaged fluid velocity and the speed of sound can be calculated.

Therefore, the radial component of the fluid velocity is negligible.

To evaluate the kinetic-energy term, the fluid velocity is needed.

Turbulence which is an erratic variation in space and time of local fluid velocity.

The transit time difference is proportional to fluid velocity.

Let be the fluid velocity outside the boundary layer, where and are both parallel.

Thus we will assume no change in fluid velocity across the actuator disk.

Thus we can arrive at an expression for the fluid velocity far downstream:

Static charge generation in these systems is best controlled by limiting fluid velocity.

Therefore, the absolute fluid velocity decreases through this as shown in the figure.