MaPFlow-Actuator Line Computations For Wind Turbine Wake Aerodynamics

When the wind passes through the rotating blade,the speed of the wind will decrease and the turbulence intensity will increase,this phenomenon is wake effect.Knowing the flow speed deficit behind a wind turbine is necessary before the installation of a wind farm in order to accurately predict the energy generated.The losses generated in flow limit the power output of a wind turbine,so the study of wake effect would contribute to improving wind farm output and forcasting.In this thesis,a MaPFlow-Actuator line model is used to study the wind turbine wake aerodynamic.Actuator line model represents the blade with a rotating body force,this representation circumvents the explicit calculation of the blade boundary layers, reducing computational cost and easing mesh generation.First,the computations was performed using MaPFlow-Actuator line mode to simulate the aerodynamic parameters of the MEXICO wind turbine in the wind tunnel conditions,the comparisons of blade loading showed that the results are in good agreement with the measurements.Then unsteady simulations of the MEXICO wind turbine wake aerodynamic was carried out using the MaPFlow-Actuator line model for three commonly defined test cases at wind speeds of 10m/s,14.7m/s and 24.12m/s.The simulation results are also compared with the measurements. The results showed: the axial velocity decreases alone the blade span wise;When the tip speed ratio is big,the speed deficit phenomenon is serious. Higher upstream velocity will reduce the effect of wake expansion.At last,the simulations of the wake characteristic of wind turbine in the atmosphere boundary layer conditions is carried out using the MaPFlow-actuator line mode,results showed that the distribution of grid lines near the wind turbine will influence the wake speed deficit.