Dynamic pressure

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In fluid dynamics, dynamic pressure (denoted by q or Q and sometimes called velocity pressure) is the quantity defined by:^[1]

${\displaystyle q={\frac {1}{2}}\rho \,u^{2}}$

where (in SI units):

• q is the dynamic pressure in pascals (i.e., N/m²,
• ρ (Greek letter rho) is the fluid mass density (e.g. in kg/m³), and
• u is the flow speed in m/s.

It can be thought of as the fluid's kinetic energy per unit volume.

For incompressible flow, the dynamic pressure of a fluid is the difference between its total pressure and static pressure. From Bernoulli's law, dynamic pressure is given by

${\displaystyle p_{0}-p_{\text{s}}={\frac {1}{2}}\rho \,u^{2}}$

where p₀ and p_s are the total and static pressures, respectively.