New-wall modeling for complex flows using the large eddy simulation technique in curvilinear coordinates

This investigation presents modifications and improvements to the dynamic subgrid scale model and introduces a new-wall model. These modifications are implemented in the large eddy simulation technique in curvilinear coordinates. They are then validated and tested in three-dimensional complex geometries. The large eddy simulation method captures many scales of turbulence up to the grid size. A closure model is used to simulate subgrid turbulence. The Smagorinsky and dynamic subgrid models are presented and tested. The dynamic model overcomes many of the deficiencies of the Smagorinsky subgrid scale model. Spatial and temporal low-pass filters have been introduced in the dynamic subgrid scale model for numerical stability. Several near-wall models are considered for the large eddy simulation technique. A local averaging technique lends these models to be applicable in complex geometry situations. A new model is introduced which overcomes planar averaging near the wall and captures ejection and sweep effects. These models have been implemented in a large eddy simulation computer program. Results are validated and tested in a lid driven cavity flow at Reynolds number of 10 000. A single tube in a channel is simulated to show the applicability of the models to complex geometries with attachment and separation as well as end-wall effects. The shedding effect was captured and turbulence statistical characteristics were acceptable.