Rheology of a Dilute Suspension of Spheres in a Viscoelastic Fluid Under Large Amplitude Oscillations

Dilute suspensions of spheres in a viscoelastic liquid under oscillatory shear flow are studied via numerical simulations. In linear viscoelastic regime, the 3D finite element simulation results agree with the analytical results from Palierne (1990). The analysis is extended to Large Amplitude Oscillations (LAOS). The rotation rate of the sphere as well as the bulk rheology are investigated. The moduli increase when particles are added into the fluid, in agreement with experimental findings. In the nonlinear range both moduli are found to be decreasing functions of the forcing amplitude. The non-linear response of the material is also illustrated by performing a Fourier analysis of the bulk shear stress signal which shows the appearance of higher harmonic contributions