Static pressure

From Glossary of Meteorology
Revision as of 17:58, 25 April 2012 by imported>Perlwikibot
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)



static pressure

In engineering fluid mechanics, the pressure in a homogeneous incompressible fluid in steady flow along a level streamline at points other than the stagnation point.

Thus if p is the static pressure, Bernoulli's equation gives
ams2001glos-Se61
where ρ is the density of the fluid, V the speed, and p1 the pressure at the stagnation point, called the total pressure. The kinetic energy per unit volume (1/2)ρV2 is
also called the dynamic pressure. The static pressure is that measured by a barometer moving with the fluid. Since the static pressure is the pressure in the moving fluid and is distributed along the streamline exactly as the hydrodynamic pressure, the terminology is most unfortunately chosen. Since it is rigorously defined only when Bernoulli's equation applies, meteorologists do well in avoiding the term. The unqualified term "pressure" is quite satisfactory in this connection. However, the instrumental precautions taken in measuring the static pressure in fluid mechanics must also be applied to meteorological barometers so that it is the pressure and not the wind speed that is being measured. The measured meteorological pressure is in approximate hydrostatic equilibrium because of the relatively small vertical accelerations in the atmosphere, but this condition does not ordinarily obtain in those studies in which the concept of static pressure is used. Thus static pressure and hydrostatic pressure must be distinguished.


Copyright 2022 American Meteorological Society (AMS). For permission to reuse any portion of this work, please contact permissions@ametsoc.org. Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act (17 U.S. Code § 107) or that satisfies the conditions specified in Section 108 of the U.S.Copyright Act (17 USC § 108) does not require AMS’s permission. Republication, systematic reproduction, posting in electronic form, such as on a website or in a searchable database, or other uses of this material, except as exempted by the above statement, require written permission or a license from AMS. Additional details are provided in the AMS Copyright Policy statement.