Dynamic pressure

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Velocity pressure is also called fluid dynamic pressure or Q given by the equation. This gives rise to the concept of Max Q, which is commonly associated with the point at which the Space Shuttle experiences its maximum load during liftoff and is mentioned in radio communications during launch.

q=\frac{1}{2} \rho v^2

By applying the ideal gas law:

p = ρRT

the definition of Mach number:

Ma=\frac{V}{a} or V=a\, Ma

and the definition of speed of sound:

a=\sqrt{k R T}

Dynamic pressure can be rewritten as:

q=\frac{k}{2} p Ma^2

This form is useful for the analysis of aircraft.

ρ = Density
q = Dynamic pressure
V = Velocity
p = Freestream pressure
Ma = Mach number
a = Speed of sound
k = a Gas constant, which is 1.4 for air
R = a Gas constant, which is 1716(US) or 286(metric) for air

A fluids dynamic pressure results from the fluids kinetic energy. A fluids total pressure is the sum of the fluids dynamic pressure and the fluids static pressure.

Velocity pressure + Static pressure + pressure altitude = Total pressure

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