Colloidal suspensions consisting of micron and larger particles dispersed in a fluid medium, often water, are important for wide variety of technological applications. For example, aqueous-phase suspensions of colloidal particles are central to oil and gas production, comprising water-based drilling fluids, reservoir stimulation and fracturing fluids and fluids for reservoir conformance control. Additionally, good placement properties are important in the application of concrete, another important colloidal suspension. The fluid-structure interaction capabilities of Uintah are being used here to perform simulations of particle-laden flows in simple geometries from which an effective viscosity can be computed for the suspension. Constituent properties of the fluid and polymers will come from molecular dynamics simulations.