NACA0012 airfoil under static and dynamic inflow conditions at Reynolds numbers between 50,000 and 150,000

The flow past a NACA0012 airfoil at Reynolds numbers between 50,000 and 150,000 is investigated using experiments and numerical simulations. In this range of Reynolds numbers, under static inflow conditions, the flow may exhibit laminar separation, laminar-to-turbulent transition and reattachment. The resulting flow topology is highly dependent on angle-of-attack and Reynolds number and is typically associated with the non-linear dependency of lift to angle-of-attack. Here, we first characterize the flow topology for various Reynolds numbers and angles-of-attack and correlate it with lift production through the force partitioning method. Second, we evaluate the influence of dynamic inflow conditions on the flow topology described earlier. Specifically, a large amplitude, low frequency variation in freestream velocity is found to affect the location of laminar separation, laminar-to-turbulent transition and reattachment under the influence of unsteady effects and streamwise pressure gradients. These effects are quantified by comparing the unsteady flow response to the quasi-steady response obtained from experiments and simulations under static inflow conditions. Again, the change in flow topology due to unsteady effects is correlated to the change in lift production through the force partitioning method. Overall, relatively good agreement is observed between experiments and simulations.