Direct Numerical Simulation of Turbulent Katabatic Slope Flows with an Immersed-Boundary Method

作者：Umphrey Clancy; DeLeon Rey; Senocak Inanc^*

来源：Boundary-Layer Meteorology, 2017, 164(3): 367-382.

DOI：10.1007/s10546-017-0252-3

• Direct numerical simulation
• Immersed-boundary method
• Katabatic flows
• Stable stratification
• Turbulence

We investigate a Cartesian-mesh immersed-boundary formulation within an incompressible flow solver to simulate laminar and turbulent katabatic slope flows. As a proof-of-concept study, we consider four different immersed-boundary reconstruction schemes for imposing a Neumann-type boundary condition on the buoyancy field. Prandtl's laminar solution is used to demonstrate the second-order accuracy of the numerical solutions globally. Direct numerical simulation of a turbulent katabatic flow is then performed to investigate the applicability of the proposed schemes in the turbulent regime by analyzing both first- and second-order statistics of turbulence. First-order statistics show that turbulent katabatic flow simulations are noticeably sensitive to the specifics of the immersed-boundary formulation. We find that reconstruction schemes that work well in the laminar regime may not perform as well when applied to a turbulent regime. Our proposed immersed-boundary reconstruction scheme agrees closely with the terrain-fitted reference solutions in both flow regimes.

• 出版日期2017-9