Numerical Study on Wind Turbine Wakes Under Thermally-Stratified Conditions

Abstract

In the present work, the wake behavior of wind turbines operating under thermallystratified atmospheric boundary layer (ABL) is numerically investigated. The steady state three dimensional Reynolds-Averaged Navier-Stokes (RANS) equations, combined with actuator disk approach, are used in the simulation. The standard ݇-ߝ turbulence model as well as two modified models namely Crespo model and El kasmi model are adopted. Two different methods are used and compared, to represent the atmospheric stratification conditions. In the first method, the energy equation is considered along with mass, momentum, and turbulence model equations. The stratification in the second method is modeled by means of an additional buoyancy production or dissipation term, which is added to the equation of the turbulent kinetic energy, instead of solving the energy equation. The results obtained from both methods show reasonable agreement with the experimental data available from the literature.

The Impact of Different Inflow Conditions on the Wake of Horizontal Axis Wind Turbine

“…The turbulence model, suggested by El Kasmi and Masson [18], was modified by Abuhegazy et al [16] to represent the buoyancy generated turbulence. This modification allows to perform the simulation of the thermally-stratified ABL without the need to solve the energy equation.…”

“…This modification allows to perform the simulation of the thermally-stratified ABL without the need to solve the energy equation. Such model is adopted for the turbulence modulation with the model equations, reported in Abuhegazy et al [16].…”

“…Moreover, the amount of the wake deficits and the available wind power in the wake region have been calculated at different downstream locations from the turbine in order to identify the required downstream distance for installing another wind turbine. Abuhegazy et al [16] tested the standard -model as well as the two modified models of Crespo et al [17] and El Kasmi and Masson [18] for the turbulence modulation in studying the wind turbine wakes behavior. It was pointed out from their study that, the modified version of the standard -model, suggested by El Kasmi and Masson [18], gives satisfactory results as compared with the reported experimental data.…”