Quasi static and dynamic stall computations applying a Navier-Stokes solver with K-ε and Baldwin-Lomax turbulence modelling

This report presents results on 2 D Quasi Static and Dynamic Stall on airfoils. The results are obtained by applying the Navier - Stokes code ElipsSys2D with both a #KAPPA# - #epsilon# and a Baldwin - Lomax turbulence model. The results concerns computations made on the NACA 0012 and NACA 62_1218 airfoils.

The work addresses the following questions related to Quasi Static and Dynamic Stall: 1) What is the difference between an oscillating inflow and a oscillating airfoil? 2) Which direction do the loops takes before Stall, in light and deep Dynamic Stall for different Reynolds numbers, amplitude in angle of attack and in reduced frequencies? 3) How well does the results from the Dynamic Stall models base on 2 D Navier - Stokes equations compare to measurements taken at the mid blade segment of a Horizontal Axis Wind Turbine operating in natural conditions? 4) What is the contribution to Dynamic Stall from respectively the time variation in relative velocity and angle of attack in the incoming flow? 5) What is the contribution to Dynamic Stall when the relative velocity and angle of attack in the incoming flow is in phase and counter phase. 6) Is it important to apply the unsteady Navier - Stokes equations instead of the steady equations when predicting Quasi Static Stall? 7) How does the choice of turbulence model influence the accuracy of the results, when modelling Quasi Static light and deep Stall? (au) 28 ills., 22 refs..