Three-dimensional numerical computations have been carried out for flow past a surface mounted finite height circular cylinder using Open Source Field Operation and Manipulation. Flow field characteristics have been investigated for fixed Reynolds number equal to 300 and varying aspect ratios (AR being the ratio of height to diameter of the cylinder) from 1 to 5. The effect of nonuniform flow (linear shear) with shear intensity (K) ranging from 0 to 0.3 on flow field characteristics has been examined using iso-Q surfaces and streamline plots. Three different flow regimes are reported based on the values of AR and K: steady flow, symmetric mode, and antisymmetric mode of vortex shedding. The formation of critical points (impingement point, source, and spiral node) has been explained using the time-averaged flow field in the longitudinal plane of symmetry. Surface flow topology has been presented with the help of limiting streamlines on the surface of the cylinder. Variation in mean drag coefficient with a change in K has also been reported. Unsteady periodic and aperiodic wake flows have been characterized using the Hilbert spectra of the transverse velocity signal at a point in the wake. The extent of nonlinear interaction in the wake and its influence on frequency distribution have been analyzed using marginal spectra and quantified in terms of degree of stationarity.

This study employs blade-resolved computational fluid dynamics simulations to investigate the aero-elastic loads on a yawed NREL 5MW wind turbine subject to full and partial wind gusts. A novel spatial gust representation, tailored towards application to large eddy simulations, is introduced. This methodology permits the injection of gusts with customizable spatial dimensions inside the flow domain. Simulations are conducted with gusts having the same diameter as the turbine rotor, half rotor diameter, and asymmetric impact with respect to the center of rotation of the turbine. Simulations of the turbine under yawed conditions are also considered. The flow characteristics are reported using contours and iso-surfaces of velocity magnitude and Q-criteria. Insights into the load characteristics of the turbine are described using torque, thrust, and root bending moments. This research highlights that partial gust impact contributes to noteworthy load fluctuations and blade tip deformations, stemming from the imbalance in force distribution across the rotor plane.

This study uses Large Eddy Simulation (LES) based on the Lattice Boltzmann Method (LBM) to investigate the impact of complex urban morphologies on downstream wind turbine arrays. Using a geometry-resolved representation of an urban canopy, the research analyzes the evolution of the urban wake and its subsequent effect on the power and thrust characteristics of a four-turbine cluster. To assess the impact of proximity and layout topology, both inline and staggered configurations are evaluated across varying separation distances ( S ) between the city edge and the turbine array. Results indicate that the urban canopy induces a substantial momentum deficit and elevated turbulence levels that dominate turbine inflow conditions. Turbulence intensities of approximately 15% are observed at hub height, even at a distance of 1000 m from the urban canopy. This enhanced shear-driven mixing accelerates internal wake recovery, rendering the performance difference between inline and staggered layouts negligible at a turbine-to-turbine spacing of five rotor diameters. Analysis of the lateral flow field reveals that urban canopy-induced “streaks” persist significantly downstream, causing spanwise power discrepancies. Notably, the urban wake remains in a developmental phase even at a fetch of fifteen rotor diameters, suggesting that the total separation distance from the urban boundary is a more critical determinant of performance than the internal array arrangement for the chosen turbine-to-turbine spacing. These findings highlight the need for strategic micro-siting that accounts for the three-dimensional maturation of the urban wake.