AbstractsEngineering

The studies in this thesis simulated straight line flow and tornado-like vortex flow. The goal of the work was to develop computational simulations of flow past rough surfaces using straight-line flow as a starting point to develop simulations of tornado flows. Analysis of turbulent boundary layer development in the straight line flow was carried out both at the computational domain's outlet, which imitate the inlet of the test section of the straight line wind tunnel and in the regions immediately next to the riblets, which were used to generate the turbulence and to accelerate the boundary layer developments. These distributions and boundary layer thickness agreed reasonably with experimental results. The numerical distributions of velocities were studied in the tornado-like vortex flow both in the far field with large radius of maximum wind (RMW) and in the central region. Vortical structures in the tornado-like vortex flow, especially those in the central region were identified and studied. These structures agrees somewhat with previous numerical studies by Lewellen(1997) and Nolan(2000). New vortical structures, horizontal vortex and double vortex rolls were identified. These structures were analyzed and explained physically with respect to the development of flow field. While the project did not proceed to the point of simulating vortex flows with rough surfaces, the foundation was laid for rough-wall work to be added to these results.