, , , , , THEORY OF THE RESONANT METHOD FOR DETERMINING THE COMPLEX SHEAR MODULUS OF LIQUID // BSU Bulletin. Mathematics, Informatics. - 2022. №1. . - С. 45-56.

THEORY OF THE RESONANT METHOD FOR DETERMINING THE COMPLEX SHEAR MODULUS OF LIQUID

DOI: 10.18101/2304-5728-2022-1-45-56 UDK: 534.21:532.135

Shear elasticity should appear at high megahertz frequencies according to existing fluid theories. However, low-frequency (100 kHz) shear elasticity in all liquids independently of their viscosity and polarity was discovered for the first time in our team. It was assumed that a low-frequency viscoelastic relaxation process exists in liq- uids. It is possible that dynamic movements of large groups of molecules appear by low-frequency shear action on the liquid layer. Therefore, further comprehensive de- tailed studies of low-frequency shear elasticity by various methods are of fundamental importance for the physics of liquids. A piezoelectric crystal of rectangular shape for shear action on the studied liquid layer at low frequencies is used in the resonance method. A liquid layer covered with a solid cover-plate is applied to the horizontal face of the piezoelectric quartz. The liquid layer experiences dynamic shear deformations when the piezoelectric quartz oscillates at a resonant frequency and a shear wave is excited in this liquid layer. The general solution to the problem of interaction of the oscillatory system “the piezoelectric quartz — the interlayer of the liquid — the coverplate” is considered in the work. The values of the real shear modulus and the mechani- cal losses angle are calculated from the parameters of the shear wave.

piezocrystal, impedance, resonant frequency, oscillations, attenuation, wave equation, shear modulus, the tangent of the mechanical losses angle, additional bond, shear wave.