Acoustic Characteristics of Fresh Tea Leaves

Abstract

The acoustic characteristics of sound fresh tea leaves were determined nondestructively by ultrasonic transmission analysis. As thickness increases, phase velocity and wavelength increase, and damping ratio and dynamic viscosity decrease, suggesting development of the fibrous tissues, accompanied by frequency convergence. The velocities of all the leaves studied were smaller than that of pure water. Decrease in viscoelasticity corresponds to increase in dynamic modulus. Thus, acoustically, we can regard the leaves as natural quasi-polymers with high viscoelasticity.