Model-form uncertainty quantification in RANS simulations of wakes and power losses in wind farms

TY - JOUR

T1 - Model-form uncertainty quantification in RANS simulations of wakes and power losses in wind farms

AU - Eidi, Ali

AU - Ghiassi, Reza

AU - Yang, Xiang I. A.

AU - Abkar, Mahdi

PY - 2021/12

Y1 - 2021/12

N2 - Reynolds-averaged Navier-Stokes (RANS) is one of the most cost-efficient approaches to simulate wind-farm-atmosphere interactions. However, the applicability of RANS-based methods is always limited by the accuracy of turbulence closure models, which introduce various uncertainties into the models. In this study, we estimate model-form uncertainties in RANS simulations of wind farms. For this purpose, we compare different RANS models to a large-eddy simulation (LES). We find that the realizable k −ϵ model is a representative RANS model for predicting the mean velocity, the turbulence intensity, and the power losses within the wind farm. We then investigate the model-form uncertainty associated with this turbulence model by perturbing the Reynolds stress tensor. The focus is placed on perturbing the shape of the tensor represented by its eigenvalues. The results show that the perturbed RANS model successfully estimates the region bounding the LES results for quantities of interest (QoIs). We also discuss the effect of perturbation magnitude on various QoIs.

AB - Reynolds-averaged Navier-Stokes (RANS) is one of the most cost-efficient approaches to simulate wind-farm-atmosphere interactions. However, the applicability of RANS-based methods is always limited by the accuracy of turbulence closure models, which introduce various uncertainties into the models. In this study, we estimate model-form uncertainties in RANS simulations of wind farms. For this purpose, we compare different RANS models to a large-eddy simulation (LES). We find that the realizable k −ϵ model is a representative RANS model for predicting the mean velocity, the turbulence intensity, and the power losses within the wind farm. We then investigate the model-form uncertainty associated with this turbulence model by perturbing the Reynolds stress tensor. The focus is placed on perturbing the shape of the tensor represented by its eigenvalues. The results show that the perturbed RANS model successfully estimates the region bounding the LES results for quantities of interest (QoIs). We also discuss the effect of perturbation magnitude on various QoIs.

KW - CFD RANS

KW - Power deficit

KW - Turbulence modeling

KW - Uncertainty quantification

KW - Wind-farm wakes

U2 - 10.1016/j.renene.2021.08.012

DO - 10.1016/j.renene.2021.08.012

M3 - Journal article

SN - 0960-1481

VL - 179

SP - 2212

EP - 2223

JO - Renewable Energy

JF - Renewable Energy

ER -