Terms To Know.
Free Stream Velocity: The velocity with which the air hits the airplane or byd33 link alternatif, the airplane hits the air. Denoted by Vinfinity . [Assume V in this case!]
Dynamic Pressure: Its is defined as the pressure that the air has by the virtue of its motion. Denoted by Pinfinity [ Assume P in this case]
Pinfinity= 0.5*d*V2
Coefficient Of Drag: It is a unit-less number that determines the lift on a body. Denoted by Cd.
Surface Area: It is the planform Area of the wing of the airplane. Denoted by S
The Coefficient of Drag is given by the equation
Cd= D/(Pinfinity*S)
Now Substitute the value of P in the equation for the coefficient of drag.
We have
Cd=D/((0.5*d*V2)*S)
Now the drag force D is given by
D=Cd*0.5*d*V2*S
Thus from the above equation we can see that the drag force is directly proportional to the free stream velocity or the airspeed