Measurement of viscoelastic properties of non Newtonian fluids

Abstract

The experimental method to measure the rheological properties of Newtonian or non-Newtonian fluids are proposed. The effects of fluids on flexural wave propagation characteristics of the beam structure is analyzed and used in measuring viscoelastic properties. Fluid-structure interaction has effects on the wave propagation characteristics. To monitor this change, frequency dependent variations of complex wavenumber of beam structure and fluid-structure interaction analysis are performed. To account for the fluid-structure interaction effects, the fluids are modelled as a simple viscoelastic support at one end of the beam. The measured properties are dynamic shear modulus and loss tangent. Using the proposed method, the rheological properties of various non-Newtonian fluids are measured. Viscosity standard fluids are tested to verify accuracy of the proposed method and the results show the same viscosity value of the standard fluid which is offered by manufacturer. Compared to general rotational type rheometer which has been widely used in measuring dynamic properties, the proposed method requires simple experimental setup, and it is flexible to select frequency ranges of data acquisition.