Flow characterization and stability analysis in rectangular lid-driven cavities with particle suspensions

Advisors: John Shelton.Committee members: Jenn-Terng Gau; Nicholos Pohlman.Includes bibliographical references.Includes illustrations.The lid-driven cavity is a canonical problem in the field of analytical and computational fluid dynamics where a system is comprised of a square domain of an incompressible fluid, its upper lid has a specified velocity and the remaining wall boundaries are subjected to fixed, no-slip, zero-velocity constraints. There are numerous examples found in the literature that address the validation of the system's well-known, stable behavior, which includes a primary recirculating vortex, secondary corner vortices, and a velocity profile through the center midpoint y-axis that is shown to be dependent on the Reynolds number. By increasing the cavity depth to aspect ratios of 1x1.5, other studies have suggested that a different kind of stable fluid structure develops, which includes a primary recirculating vortex, secondary corner vortices, and a new secondary recirculating vortex that developed from the corner vortices of the square cavity and merged together at the bottom of this rectangular system. Mathematical perturbations to the square lid-driven cavity problem have been shown to decrease the stability of the flow structure and exhibit 3D, turbulent flow characteristics. Particle suspensions could be used as physical representations of these mathematical perturbations. In this thesis, I will investigate how these physical perturbations affect the stable flow characteristics observed in lid-driven cavities with high aspect ratios. The base flow is two-dimensional and is computed numerically over a range of Reynolds numbers and is perturbed with varying volume fractions and types of particle suspension. Using Ergun-Wen-Yu drag and particle slip velocities are used to represent particle-fluid interactions. In this investigation, open-source CFD software called OpenFOAM will be used to solve the Navier-Stokes equations for the fluid phase and particle-particle interactions for the solid phase. The purpose of these studies and analyses will aid in the future findings of advantageous methodologies to determine the flow characterization of drilling mud.M.S. (Master of Science