Drag Coefficient

Drag coefficient is proportional to { (gravitational force) / (inertial force) } and is used in momentum transfer in general and free settling velocities and resistance to flow calculations in particular. It is normally defined in the following form:

 

Where:
g	=	Gravitational acceleration
L	=	Characteristic dimension of object
rho	=	Density of object
rho_f	=	Density of surrounding fluid
V	=	Velocity

Pressure Coefficient

The pressure coefficient is is the ratio of pressure forces to inertial forces and can be expressed as
C_p = dP/(ρ v² /2)
    = dh (ρ v² /2 g)          (1)
where
C_p = pressure coefficient
dp = pressure difference (N)
ρ = fluid density (kg/m³)
v = flow velocity (m/s)
dh = head (m)
g = acceleration of gravity (= 9.81 m/s²)
The pressure coefficient is important in most fluid flow applications.

Pressure Coefficient Comparison Between Calculation (lines) and Experiment Around an Airfoil
Lift coefficient

The lift coefficient ( or ) is a dimensionless coefficient that relates the lift generated by a lifting body, the dynamic pressure of the fluid flow around the body, and a reference area associated with the body. A lifting body is a foil or a complete foil-bearing body such as a fixed-wing aircraft.
Lift coefficient is also used to refer to the dynamic lift characteristics of a two-dimensional foil section, whereby the reference area is taken as the foil chord.^[1][2]
Lift coefficient may be described as the ratio of lift pressure to dynamic pressure where lift pressure is the ratio of lift to reference area.
Lift coefficient may be used to relate the total lift generated by a foil-equipped craft to the total area of the foil. In this application the lift coefficient is called the aircraft or planform lift coefficient
Watercraft and automobiles equipped with fixed foils can also be assigned a lift coefficient.
The lift coefficient is equal to: