Page 68 - 48Fundamentals of Compressible Fluid Mechanics

30 CHAPTER 3. SPEED OF SOUND

Fig. 3.3: The Compressibility Chart

The speed of sound of any gas is (3.7). To obtain the expression for gas that obey
the law expressed by (3.19) some mathematical expression are needed. Recalling
from thermodynamics, the Gibbs function (3.20) is used to obtain

(3.20)

The definition of pressure specific heat for a pure substance is
(3.21)

The definition of volumetric specific heat for a pure substance is

(3.22)