Brief communication: Wind-speed-independent actuator disk control for faster annual energy production calculations of wind farms using computational fluid dynamics

Abstract

Abstract. A simple wind-speed-independent actuator disk control method is proposed that can be applied to speed up annual energy production calculations of wind farms using Reynolds-averaged Navier–Stokes simulations. The new control method allows the user to simulate the effect of different wind speeds in one simulation by scaling a calibrated thrust coefficient curve, while keeping the inflow constant. Since the global flow is not changed, only the local flow around the actuator disks need be recalculated from a previous converged result, which reduces the number of required iterations and computational effort by a factor of about 2–3.

Faster wind farm AEP calculations with CFD using a generalized wind turbine model

“…The AEP calculations are performed with a relatively low convergence criterion of 10 −4 (which means that the equation residuals are reduced by factor 10 −4 with respect to the initial condition representing the inflow). This reduces the number of required iterations by an order of magnitude, while the converge error in terms of AEP is only 0.02% [11]. The other studies (Sects.…”

“…Mathematical definitions of mirrorand rotational symmetry of a planar point set can be found in Highnam (1986) [19]. While mirror-symmetric simulation setups are commonly used in idealized studies [11], rotationalsymmetric simulation setups are not widely employed to our best knowledge. A mirrorsymmetric simulation setup represents a wind farm layout in flat terrain including one or more axes of mirror-symmetry and neglects wake deflection caused by wake rotation and shear, yaw misalignment, and Coriolis-induced wind veer.…”

“…Wind farms situated in homogeneous terrain can be simulated faster in RANS by running consecutive wind direction flow cases, where the effect of a new wind direction is represented by rotating the wind farm layout, while keeping the inflow wind direction constant, as shown in previous work [11]. Once the first simulation has converged, the subsequent simulation (corresponding to a different wind direction) only needs to recalculate local changes, while the global flow is similar to the first simulation result.…”

“…Once the first simulation has converged, the subsequent simulation (corresponding to a different wind direction) only needs to recalculate local changes, while the global flow is similar to the first simulation result. This method can be employed to reduce computational effort of AEP calculations using RANS by a factor 2 to 3, as shown for a single wind farm layout case [11]. In addition, Reynolds-number similarity can also reduce the computational effort by a factor 2 to 3, by running wind speed flow cases consecutively.…”

Advancing Wind Resource Assessment in Complex Terrain with Scanning Lidar Measurements

“…This assumption is supported by a dimensional analysis based on Monin-Obukhov similarity theory (MOST). The scaling behavior has been re-evaluated recently in [18,19].…”