UNSTEADY FLOW SIMULATIONS AROUND COMPLEX GEOMETRIES USING STATIONARY OR ROTATING UNSTRUCTURED GRIDS

Open Access
Author:
Sezer-Uzol, Nilay
Graduate Program:
Aerospace Engineering
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
August 02, 2006
Committee Members:
  • Lyle Norman Long, Committee Chair
  • Philip John Morris, Committee Member
  • Edward C Smith, Committee Member
  • Joseph Francis Horn, Committee Member
  • Yousry Azmy, Committee Member
Keywords:
  • unsteady flow
  • ship airwake
  • wind turbine
  • large eddy simulation
  • LES
  • unstructured
  • computational fluid dynamics
  • CFD
Abstract:
In this research, the computational analysis of three-dimensional, unsteady, separated, vortical flows around complex geometries is studied by using stationary or moving unstructured grids. Two main engineering problems are investigated. The first problem is the unsteady simulation of a ship airwake, where helicopter operations become even more challenging, by using stationary unstructured grids. The second problem is the unsteady simulation of wind turbine rotor flow fields by using moving unstructured grids which are rotating with the whole three-dimensional rigid rotor geometry. The three dimensional, unsteady, parallel, unstructured, finite volume flow solver, PUMA2, is used for the computational fluid dynamics (CFD) simulations considered in this research. The code is modified to have a moving grid capability to perform three-dimensional, time-dependent rotor simulations. An instantaneous log-law wall model for Large Eddy Simulations is also implemented in PUMA2 to investigate the very large Reynolds number flow fields of rotating blades. To verify the code modifications, several sample test cases are also considered. In addition, interdisciplinary studies, which are aiming to provide new tools and insights to the aerospace and wind energy scientific communities, are done during this research by focusing on the coupling of ship airwake CFD simulations with the helicopter flight dynamics and control analysis, the coupling of wind turbine rotor CFD simulations with the aeroacoustic analysis, and the analysis of these time-dependent and large-scale CFD simulations with the help of a computational monitoring, steering and visualization tool, POSSE.