LARGE-EDDY SIMULATION OF A BUOYANT PLUME PAST A BLUFF BODY

A large-eddy simulation (LES) of a buoyant plume past a bluff body is performed. A round heat source is placed at the center of a horizontal flat wall, and a bluff body in the shape of a thick round plate is floating right above the heat source. The modified Rayleigh number based on the total heat input is set at 1.2x10(10). On the basis of past studies, the Smagorinsky model is adopted as a subgrid-scale (SGS) model, and a partial slip boundary condition based on the wall law is applied to a horizontal flat wall and a disk surface. The validity of numerical results is ascertained by comparison with theoretical solution and experimental data. The blocking of upward flow and imparting turbulence through a bluff body vary the process of developing a buoyant plume, while properties of a fully developed plume rarely vary. With heat from a bluff body, another buoyant plume is formed near the center, piled with upward flow passing around the bluff body. Moreover, main positions of buoyant production of turbulent kinetic energy move a point from near the side of the bluff body to a point near the central axis. This affects the transition to a fully developed plume in turbulence statistics.