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Incompressible fluid does not exist but in many practical applications the pressure and temperature variations stay within the sufficiently narrow range where a fluid can be considered as incompressible.
The concept of incompressible Incompressible fluid should should not be confused with Incompressible flow. The latter can develop even for compressible
See also
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Physics / Mechanics / Continuum mechanics / Fluid Mechanics / Fluid Dynamics
[ Compressibility ] [ Incompressible matter ] [ Incompressible flow ]
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