The Simulation of the Flow Generated by the Interaction Between an Inlet and a Cross-Flow

The flow generated by the interaction between an inlet and a cross-flow are frequently found in many engineering and industry application, example is at the inlet of air duct in ventilation system. The simulations were using the experimental data to be the reference.^1,2 The simulation was investigated using the Large Eddy Simulation (LES) where the small scales of turbulence are modelled by following the Smagorinsky idea’s.³ Three different inflow boundary conditions, steady uniform, steady profile and turbulent, were tested. The results downstream of the intake are very sensitive to the turbulent inflow compared to the steady inflow when the mesh in coarse. In particular the turbulent inflow condition case shows the streamwise vortices downstream whist the steady inlet does not show these vortices. These vortices were not mentioned in the experiment results. The vortices can only be observed for the turbulent inlet conditions results in a coarse mesh. This implies that when the meshes are too big, the numerical viscosity could be significant. An artificial turbulent condition needed to be applied to show these turbulence phenomena. Whilst when the mesh resolution was increased, the smaller scale of flow can be solved and it can show these turbulent phenomena by itself.