Executive Summary : | The management of turbine wake losses in wind farms is crucial for optimal wind resource utilization. These farms are often located on surfaces with varying aerodynamic roughness properties, which can affect the performance of wind turbines. Analytical models have been developed to a limited extent, but this proposal aims to develop analytical models using large-eddy simulations (LES) for wind farm performance on heterogeneously rough/patchy ground surfaces. The goal is to create a semi-analytical modelling framework that predicts mean flow and turbulent statistics in the wake of a wind farm on these surfaces. Previous work has focused on conducting LES of wind farms on irregular band/patch aerodynamic roughness geometries and developing models for wind speed and turbulence intensity. The current proposal builds on previous work by developing reduced models that account for two successive abrupt surface roughness jumps. The model will be based on the hypothesis that the flow downstream of a band of elevated surface roughness can be divided into four vertical regions separated by an 'equilibrium layer' and two 'internal boundary layers'.
The project will also conduct high-fidelity LES for several parameters using a well-validated in-house solver, considering different combinations of heterogeneity bands, roughness jump strength, turbine thrust coefficients, and turbine locations. The data generated from these numerical experiments will enable detailed physical understanding of mechanisms involved in mean and turbulent kinetic energy entrainment and partitioning. If successful, this project could lead to improved analytical models for wind farm design, ultimately improving wind resource utilization in the country and worldwide. |