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Synonym: Heat Capacity Ratio (γ) = Adiabatic Index (γ) = Isentropic expansion factor (κ) = Isentropic exponent (κ)

Ratio between Isobaric heat capacity   and Isochoric heat capacity :

\gamma = \frac{C_P}{C_V}

Since  is the ratio it can be equivalently represented by intensive properties:

\gamma = \frac{c_P}{c_V} = \frac{c_{Pm}}{c_{Vm}}= \frac{c_{Pv}}{c_{Vv}}

where

The Heat Capacity Ratio can be equivalently represented as ratio of Isothermal Compressibility  and Isentropic Compressibility :

\gamma=\frac{c_P}{c_V}=\frac{\beta_T}{\beta_S}= \kappa

wich is often denoted as  and referred as Isentropic exponent.

The Heat Capacity Ratio for ideal gases is:

\gamma = 1 + \frac{2}{f}

where

Heat capacity ratio for various fluids ^[1]: 

In express analysis of petroleum fluids (including liquid water and vapour) the Heat Capacity Ratio can be assumed .

See also

Physics / Thermodynamics / Thermodynamic process 

[ Mayer's relation ]

References

White, Frank M. (October 1998). Fluid Mechanics (4th ed.). New York: McGraw Hill. ISBN 978-0-07-228192-7.