M.S. (Master of Science)
Department of Mechanical Engineering
The lid-driven cavity is a canonical problem in the field of analytical and computational fluid dynamics. This work is focused on a 2-D rectangular cavity with a length twice the size of its width and consists of an incompressible fluid with a moving upper wall/lid while the rest of the wall boundaries are subjected to fixed, no-slip, zero-velocity boundary conditions. The objective is to investigate the effect of perturbations resulting from particle drag and particle collisions on dominant flow structures of the fluid within this cavity. The dominant flow structures in a rectangular lid-driven cavity constitute a primary vortex, a secondary vortex and a corner eddy. The effects on these dominant flow structures are analyzed by varying the concentration of particles and the Reynolds numbers of the fluid. The computational tools used for carrying out this analysis includes: OpenFOAM, which is used to solve the Navier-Stokes equations for the fluid phase, particle phase, and the corresponding fluid-particle couplings; Octave, which is used to calculate the proper orthogonal decomposition on the difference field between the base and perturbation flows as well as applying Fast Fourier Transform; and ParaView, which is a
multiplatform application used for visualization and analysis. The difference field is a difference in the velocity vectors between the perturbation flow and the base flow. Modes and kinetic energies are extracted from the proper orthogonal decomposition analysis for a complete analysis to be performed. Moreover, Fast Fourier Transform is applied to analyze the data obtained from the modes and to relate it to the changes in flow behavior within the cavity. From observations and analysis performed, it was concluded that particle drag commands the dominant modes for cases with lower particle concentrations, while particle collisions command the dominant modes for cases with higher particle concentrations. Also, it was observed that the second, third and fourth modes, although their frequency is low, tend to drive the more dominant modes towards the formation of the original flow structure.
Bolisetty, Siva, "Effect of Perturbations on the Dominant Flow Structures in a Rectangular Lid-Driven Cavity with Particle Suspensions" (2019). Graduate Research Theses & Dissertations. 6876.
Northern Illinois University
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