Large-eddy simulations of turbulent flow with heat transfer in simple and complex geometries using Harwell-FLOW3D

Large-eddy simulation (LES) results are presented and discussed for the turbulent flow with heat transfer in different geometrical configurations, including a plane channel, a channel bearing transverse square ribs on one of the walls, and a crossed-corrugated air heater. They were obtained using the computational fluid dynamics (CFD) code Harwell-FLOW3D (Release 2), finite-volume grids having up to 42(3) nodes, and the Smagorinsky subgrid model with several variants regarding near-wall damping and wall boundary conditions. The first problem (plane turbulent Poiseuille flow with heat transfer) was mainly used as a benchmark to investigate the influence of numerical methods (pressure-velocity coupling algorithm, discretization scheme for the advection terms, time stepping and value of the time step, number of grid points) and modelling options (magnitude of the Smagorinsky constant, near-wall damping form of the wall boundary conditions, subgrid Prandtl number) against experimental data and literature LES-direct simulation (DS) results. The two problems in complex geometries were studied with the main purpose of testing the potentialities of LES as a predictive tool of engineering and industrial interest when coupled with a powerful general-purpose CFD code.