An Improved Rigid Sphere Equation of State and Calculation of Absorption Coefficients of Sound Due to Thermal and Viscous Losses

Caranhan and Starling obtained an equation of state for rigid spheres from an analysis of the reduced virial series. It has been claimed that the equation describes rigid sphere behaviour better than any other existing analytical form of the equation of state. In this paper this equation has been applied to derive expressions for the attenuation of sound due to thermal and viscous losses and also for the velocity of sound through liquids. The equation for viscous losses is exactly the same as in the classical theory of sound absorption while the expression for the losses due to thermal conduction is found to be different. The expressions have been applied for the evaluation of the velocity of sound and the total absorption coefficient of sound where the internal degrees of freedom are lacking, thus no relaxation losses are involved. The calculated and experimental values are in fair agreement only, probably because of the inherent assumption of the rigid sphere model of the molecules.