Modelling of Effect of Inflow Turbulence on Large Eddy Simulation of Bluff Body Flows

A random flow generation (RFG) algorithm for a previously established large eddy simulation (LES) code is successfully incorporated into a finite element fluid flow solver to generate the required inflow/initial turbulence boundary conditions for the LES computations of viscous incompressible turbulent flow over a nominally twodimensional circular cylinder at Reynolds number of 140,000. The effect of generated turbulent inflow boundary conditions on the near wake flow and the shear layer and on the prediction of integral flow parameters is studied based on long time average results. No-slip velocity boundary function is used but wall effects are taken into consideration with a near wall modelling methodology based on van Driest Damping approach. The numerical results obtained from simulations are compared with each other and with the experimental data for different turbulent inflow boundary conditions to assess the functionality of the RFG algorithm for the present LES code and hence its influence on the vortex shedding mechanism and the resulting flow field predictions.