Blade Wake Research Articles

Optimization of Low-Pressure Turbine Blade by Means of Fine Inspection of Loss Production Mechanisms

Abstract In this study, Proper Orthogonal Decomposition (POD) was applied to Large Eddy Simulations (LES) of two high-loaded low-pressure turbine cascades under unsteady inflow conditions to investigate entropy production within different parts of the blade passage. The terms for Turbulent Kinetic Energy (TKE) production, diffusion, and dissipation from the stagnation pressure transport equation were integrated across the computational domain. The POD-based method enables the decomposition of contributions from various coherent flow dynamics to TKE production and dissipation, such as the migration, bowing, tilting, and reorientation of incoming wake filaments, as well as the breakdown of streaky structures in the blade boundary layer and the formation of Von Karman vortices in the blade wake. This approach helps designers identify the dominant POD modes (i.e., turbulent flow structures) responsible for loss generation, understand their dynamics and locate where they primarily act. Using this optimization strategy, a new low-pressure turbine profile was designed. LES calculations on the optimized geometry showed that it is possible to design a higher-loaded profile with a lower global loss coefficient. The new loading distribution, characterized by stronger acceleration in the early part of the blade passage, results in reduced upstream wake migration losses and lower TKE production in the trailing edge wake zone due to early suction side boundary layer transition.

The Matching Mechanism and Flow Mechanisms of Supersonic Through-Flow Variable-Pitch Tandem Cascade

Abstract The geometric structure of the supersonic through-flow variable-pitch tandem fan poses challenges in ensuring optimal relative blade positions across various operating modes. This study employed numerical simulations to investigate the impact of axial overlap and percent pitch on the aerodynamic performance of fan in typical modes. Furthermore, it delved into the intricate interplay between the front and rear blades, offering detailed insights into the selection principles governing the relative blade positions in the supersonic through-flow variable-pitch tandem fan. The findings underscored the pivotal role of percent pitch based on chord direction in fan's aerodynamic performance. Specifically, supersonic and transonic modes exhibited superior performance when chord direction percent pitch was set at 10% and 100%, respectively. The key factor contributing to these lower losses was the influence of low-speed fluid from the wake of the front blade, which weakened the shock boundary layer interaction on the rear blade's surface. In the high-speed windmilling mode, within the confines of geometric constraints, higher percent pitch based on chord direction values corresponded to reduced losses. This outcome was primarily attributable to the gap-blocking effect, which diminished the shock boundary layer interaction on the rear blade's pressure side and improved the wake of the rear blade. However, in this mode, the loss demonstrated a positive correlation with the pressure ratio. Consequently, the selection of the relative blade position required a delicate balance between the competing demands of these two factors.

Research on compressor cascade flow field modeling method based on finite volume flux-informed neural network

For compressor cascade flow field modeling, there exists strong velocity shear in the leading edge separation flow, boundary layer, and wake, which leads to increased modeling errors. To improve the accuracy of the flow field modeling method, this paper introduces the concept of numerical flux from the finite volume method into the loss function to implement Euler equation physics-informed learning, and a finite volume flux-informed neural network (FVFI-net) is constructed. Selecting a high-load, large-turning-angle compressor cascade as the study object, a comparative analysis is conducted on the advantages and disadvantages of purely data-driven, weak physical constraint, and finite volume flux-informed methods in compressor cascade flow field modeling. The study found that compared to purely data-driven and weak physical constraint methods, FVFI-net can reduce the average error of aerodynamic parameters in the flow field by approximately 45.6% and 29.5%, respectively, at a 0° angle of attack. For the flow separation problem occurring at the suction side leading edge and the blade wake area caused by a 5° angle of attack, FVFI-net can effectively reduce modeling errors near the leading edge, in the wake region, and near the periodic boundaries, thus reducing the average error of the aerodynamic parameters of the flow field by about 49.2%and 31.3%, respectively, compared to pure data-driven and weak physical constraint methods.

High-fidelity simulation of the interaction between a blade cascade and an ingested vortex

The aim of this research is to analyze the flow generated by the interaction between a simplified linear blade cascade adapted from an industrial aircraft engine demonstrator and an ingested vortex with the aerodynamic characteristics of a ground vortex observed in experiments. Due to the lack of availability of experimental and high-fidelity numerical studies of this phenomenon in the literature, a representative academic test case with a high-fidelity hybrid RANS/LES resolution of turbulence, namely the Zonal Detached Eddy Simulation (ZDES) technique, is performed. After the description of the computational setup and the numerical parameters used, the instantaneous topology of this complex flow is discussed, especially the interaction of the compressor cascade with the dynamics of the vortex. The simulation shows the chopping of the vortex, its destabilization and its dislocation into turbulent structures downstream the blade cascade. Turbulence is finely resolved in the blade wake and in the chopped vortex by ZDES technique at a moderate computational cost thanks to the RANS treatment of attached boundary layers with an applicative value of Reynolds number (5⋅106). A URANS simulation is also performed and allows a good representation of the averaged vortical structures inside the vortex close to the phase-averaged reference simulation. Spectral analyses are performed on unsteady velocity signals from probes located inside and outside the vortex chopped by the blades, highlighting more intense axial velocity fluctuations from turbulent structures inside the transformed vortex than in the wake of the blades, these structures being convected downstream in the direction of the Outlet Guide Vane (OGV).

Transient numerical simulation to investigate pressure fluctuation spectrum and deficit in the near wake of a horizontal axis wind turbine

Wind energy becomes one of the promised solutions as alternatives of using fossil power energy in the upcoming decades. As pressure fluctuation and flow deficit in the near wake play a crucial role in predicting the turbine performance, the novelty in the current study focuses on a three dimensional (3 D) transient numerical simulation to investigate near wake characteristics of NREL phase IV wind turbine. Pressure fluctuation spectrum and wake deficit at four sections downstream the turbine are the main parameters studied as well as the flow streams and iso-surface characteristics. The mentioned parameters are studied at four sections: (0.25 D), (0.5 D), (0.75 D), and (1 D) of turbine diameter. The obtained results are compared with corresponding data from the NREL Phase IV experiments for validation purposes. Results show that the highest-pressure fluctuation spectrum would be at the nearest wake region, and, then it decreases periodically. Hub pressure spectrum density is much lower than that density for the turbine blade. The wake deficit profile shows that the deficit is developing with time at a rate equal to (0.115 rate per sec). In addition, it was found that the wake is recovered just (1 d) of the hub diameter while the blade wake deficit becomes the dominant after (0.75 D) of turbine diameter to cover the whole wake region. It was also found that the downstream distances should be extended more to resolve the whole wake recovery. The comparison with the tests measurements shows agreement between both the numerical and experimental works such that the error doesn't pass 4.3 %.

Characterization of the Endwall Flow in a Low-Pressure Turbine Cascade Perturbed by Periodically Incoming Wakes, Part 1: Flow Field Investigations with Phase-Locked Particle Image Velocimetry

Particle image velocimetry (PIV) measurements were performed inside a low-pressure turbine cascade operating at engine-relevant high-speed and low-Re conditions to investigate the near-endwall flow. Of particular research interest was the dominant periodic disturbance of the flow field by incoming wakes, which were generated by moving cylindrical bars at a frequency of 500 Hz. Two PIV setups were utilized to resolve both (1) a large blade-to-blade plane close to the endwall as well as midspan and (2) the wake effects in an axial flow field downstream of the blade passage. The measurements were performed using a phase-locked approach in order to align and compare the results with comprehensive CFD data that are also available for this test case. The experimental results not only support a better understanding and even a quantification of the wake-induced over/under-turning inside and downstream of the passage, they also enable the tracing of the ‘negative-jet-effect’, which is widely known in the CFD branch of the turbomachinery community but is seldom visualized in experiments. The results also reveal that the bar wake periodically widens the blade wake by up to 165%, while the secondary flow is less affected and exhibits a phase lag with respect to the 2D-flow effects. The results presented here are an essential basis for the subsequent investigation of the near-endwall blade suction surface effects using unsteady pressure-sensitive paint in the second part of this two-part publication.

Acoustics and Forces from a Subscale Electric Vertical-Takeoff-and-Landing Rotor in Edgewise Flight

The far-field noise and forces of a subscale two-blade rotor were measured in an anechoic wind tunnel for both hover and edgewise flight conditions. The mean thrust and torque coefficients increased with the edgewise advance ratio in relation to the hover coefficients. The tonal and broadband noise contributions were separated and analyzed in both the time and frequency domains. The sound pressure level (SPL) at the blade pass frequency (BPF) had the greatest contribution to the overall SPL, and the dominant broadband noise source changed from high-frequency trailing edge noise to midfrequency blade wake interaction noise with an increasing edgewise advance ratio. The tip Mach number scaling of the noise sources was examined and found to be highly dependent on the oncoming freestream velocity. The BPF SPL directivity showed a dependency on the advance ratio, with a peak magnitude below and upstream of the rotor’s retreating side. The broadband noise had a dipole directivity with a minimum in the rotor plane. The midfrequency broadband noise had signatures indicative of blade wake interaction noise, and the high-frequency noise had signatures indicative of amplitude modulated trailing edge noise. The results demonstrate the importance of unsteady loading noise and broadband noise for subscale urban air mobility rotors.

Study on the Tip Leakage Loss Mechanism of a Compressor Cascade Using the Enhanced Delay Detached Eddy Simulation Method.

The leakage flow has a significant impact on the aerodynamic losses and efficiency of the compressor. This paper investigates the loss mechanism in the tip region based on a high-load cantilevered stator cascade. Firstly, a high-fidelity flow field structure was obtained based on the Enhanced Delay Detached Eddy Simulation (EDDES) method. Subsequently, the Liutex method was employed to study the vortex structures in the tip region. The results indicate the presence of a tip leakage vortex (TLV), passage vortex (PV), and induced vortex (IV) in the tip region. At i=4°,8°, the induced vortex interacts with the PV and low-energy fluid, forming a "three-shape" mixed vortex. Finally, a qualitative and quantitative analysis of the loss sources in the tip flow field was conducted based on the entropy generation rate, and the impact of the incidence on the losses was explored. The loss sources in the tip flow field included endwall loss, blade profile loss, wake loss, and secondary flow loss. At i=0°, the loss primarily originated from the endwall and blade profile, accounting for 40% and 39%, respectively. As the incidence increased, the absolute value of losses increased, and the proportion of loss caused by secondary flow significantly increased. At i=8°, the proportion of secondary flow loss reached 47%, indicating the most significant impact.

Numerical Investigations on Phase Cancelation of Interaction Noise for Counter-Rotating Propellers

The large interaction tonal noise of counter-rotating propellers significantly restricts their application in civil aviation. A pair of counter-rotating propellers was simulated by the lattice Boltzmann method, and the far-field noise was predicted by the Ffowcs Williams and Hawkings analogy. Dynamic mode decomposition was introduced to analyze the surface pressure contribution to far-field noise and to provide insights on the cancellation mechanism of the noise source distribution for the interaction tone. It was found that the cancellation effect is closely related to the relative position between the front blade wake and rear blade element. By adjusting the rear blade sweep and, hence, changing the relative position, the interaction tone can be reduced effectively.

Disentangling mechanisms responsible for wind energy effects on European bats

Mitigating anthropogenic climate change involves deployments of renewable energy worldwide, including wind energy, which can cause significant impacts on flying animals. Bats have highly contrasted responses to wind turbines (WT), either through attraction increasing collision risks, or avoidance leading to habitat losses. However, the underlying mechanisms remain largely unknown despite the expected rapid evolution of WT size and densities. Here, using an extensive acoustic sampling (i.e. 361 sites-nights) up to 1483 m from WT at regional scale, we disentangle the effects of WT size (ground clearance and rotor diameter), configuration (density and distance), and operation (blade rotation speed and wake effect) on hedgerow use by 8 bat species/groups and one vertical community distribution index. Our results reveal that all WT parameters affected bat activity and their vertical distribution. Especially, we show that the relative activity of high-flying species in the community was lower for higher WT density and lower ground clearance. Medium-flying species were sensitive to wind turbine distance, with either attraction or avoidance depending on proximity to the wake area and wind conditions. Specifically, wind turbine distance, wake effect and their interaction each affected the activity of one, three, and three species out of eight, respectively. Blade rotation and rotor diameter affected the activity of four and three species/groups, respectively, and ground clearance affected the activity of five ones. Taken together, WT configuration, operation, and size parameters affected the activity of three, five, and seven out of eight species/groups, respectively. These results call for the consideration of all these factors when assessing the ecological sustainability of future wind farms. The study especially advocates to avoid high WT densities, large rotors, and to site WT as far as possible from optimal habitats such as woody edges and not between them and the source of prevailing winds, in order to limit bats-WT interactions.

Investigating the impact of various operating parameters on blade aeroelasticity and wake characteristics of large-scale wind turbines

The current study endeavors to investigate the impact of various operating parameters on the fluid-structure interaction characteristics of wind turbine blades and wake field characteristics within a wind farm. The observed underperformance of wind farms, attributed to downstream wind turbines being exposed to upstream wake effects, highlights the need for implementing active wake control (AWC). Consequently, in-depth research into the fluid-structure interaction characteristics of wind turbines and wake characteristics under AWC conditions becomes imperative. To address this, a novel aeroelastic analysis model based on geometrically exact beam theory, lifting line theory, and optimization is developed. Numerical simulations utilizing the IEA WIND 10 MW wind turbine, developed by the International Energy Agency, are employed to assess the fluid-structure interaction characteristics of the blades and wake characteristics under various wake control strategies. The results demonstrate that cone angle control in blade attitude alters the wake field width but may reduce velocity loss recovery rate, while pitch angle control significantly improves wake field length at the expense of increased response load. Yaw and tilt control redirect wake flow, with tilt control exhibiting lower thrust and structural response loads. The coupling of yaw and tilt control emerges as a promising approach with enhanced velocity loss recovery and reduced response loads. These findings contribute to understanding the effectiveness of wake control strategies in optimizing large-scale wind turbine performance.

Nonlinear energy sink-based study on vortex-induced vibration and control of foil-cylinder coupled structure

The interference of blade wake flow can pose a threat to the safety of flexible tower structures. In order to investigate the influence of airfoil position parameters on the VIV characteristics and the vibration reduction effect of nonlinear energy sinks (NES) on the cylinder, a flexible tower under the influence of blade wake flow is used as a reference, and a dynamic simulation model of an airfoil-twin degree-of-freedom cylindrical coupled structure is established based on computational fluid dynamics (CFD), structural dynamics, and nested grid techniques. The accuracy of the numerical model established in this paper is verified by comparing it with experimental data from foreign literature. The calculation results indicate that airfoils in different positions cause changes in the amplitude and frequency ratios of the cylinder and can either delay or enlarge the frequency lock-in interval of the cylinder. Under the influence of airfoil wake, the column experiences more severe vibrations. The NES can absorb the vibrational energy of the cylinder, and setting appropriate NES parameters can reduce the resonance response between the cylinder and the shedding vortices in the wake of the airfoil. This helps to change the shedding mode of the vortex and effectively suppress the VIV of the cylinder.

Energy loss assessment of a two-stage pump under natural flow in the marine cooling system based on entropy production theory

Natural flow conditions are commonly used in the cooling systems of modern high-speed vessels and nuclear submarines. When the vessel's speed satisfies the requirements, it relies on its kinetic energy to supply seawater to the condenser in the cooling system. Under natural flow conditions, the pump is not driven, and the rotor will be “stuck” or rotated passively by the inlet flow shock. The local energy loss caused by the blade tip leakage vortex, surface separation flow, and wake flow significantly impact the system’s performance. Entropy production is an irreversible dissipation effect caused by the energy transfer process. According to the second law of thermodynamics, the entropy production theory can effectively characterize the intensity of local energy loss under natural flow conditions. In this study, the variation law of hydraulic loss and passive rotational speed under different flow rates of a two-stage pump were obtained by natural flow experiments. Moreover, the generation mechanism of intense energy loss under different natural flow conditions was investigated based on computational fluid dynamics (CFD) and entropy production theory. The results show that the entropy production induced by turbulent kinetic energy (TEP) is dominant, averaging 71.8%, followed by the wall entropy production (WEP), about 26.1%. The contribution of viscous dissipation entropy production (VDEP) can be negligible. When the impeller is “stuck” at low flow rates, entropy production is mainly from the flow separation near the blade and the flow shock region close to the guide vane back. The total entropy production of the guide vane accounts for 78%, higher than the impeller. However, when the impeller rotates passively at high flow rates, the energy loss inside the impeller is dominant, about 62%. The energy loss occurs around the blade wake region and the high velocity-gradient region near the guide vane. The flow field patterns between the two stages are similar, but the energy loss in the impeller and guide vane of stage Ⅱ is much higher. The TEP and WEP of the two impeller stages differed by 14% and 10%, respectively, and the guide vane of the two stages differed by 8% and 3%, at a flow rate of 196.8 m3/h.

Calibration of Multi Hole Pressure Probes for Three Dimensional Flow Measurements in Subsonic Flow*

The calibration of two multi hole pressure probes with four and five pressure holes are presented at three Mach numbers, viz. M=0.3, 0.4 and 0.5. The calibration was carried out in a subsonic calibration tunnel in yaw angle and pitch angle range of ± 30° at 5° interval. Calibration curves are presented and compared at the three Mach numbers. Calibration data at one Mach number are used as calibration data and calibration data at other Mach numbers are used as measured data to find the flow parameters namely, total pressure and static pressure and flow yaw angle and pitch angle using a lookup table method at these Mach numbers. The interpolation errors are small when the yaw angle and pitch angle range is from -20° to 20° for the four hole probe and from -15° to 15° for the five hole probe. Mach number effects on the flow measurements can be incorporated using the iterative method presented. This method is used to obtain flow parameters in the wake of a steam turbine rotor tip cascade blade. The differences in the obtained values using calibration coefficients at three Mach numbers are found to be negligible.

Characteristics of a tip-vortex generated by a single rotor used in agricultural spraying drone

A better understanding of downwash flow is required to increase the efficiency of unmanned aerial vehicle sprayers. The tip vortex rolled up by the rotor blade tip rotating at high speed produces a complex induced velocity field, which has an important impact on the downwash flow in the wake of the rotor. Usually, a symmetrical experimental setup with a central rotor support perpendicular to the rotation plane is used in studies on rotating blade wake and vortices, potentially leading to differences in observed wake and vortices in real situations. whereas in reality, the rotor is typically supported by a parallel arm extending below the rotor in the rotation plane. It is crucial to consider these differences for accurate results in analyzing blade rotation. The behavior of the tip vortices, dynamic characteristics, and velocity field of the rotor wake in agricultural drone single-rotor downwash flow was experimentally investigated using particle image velocimetry (PIV) combined with high-speed camera imaging. The dynamics of blade tip vortices at different wake ages and rotational speeds of the rotor, 1000–3000 rpm, were measured and analyzed. The results indicate that in the early stages of a vortex's life, tip vortices generated by rotors do not have an axisymmetric structure, and the swirl velocity in the core decreases logarithmically as the wake age increases. Vortex models were validated by examining the swirl velocity structure of the tip of the vortex. Vortices within the vortex core exhibit a comparable self-similar velocity profile to the Iverson model's laminar profile, despite the transition flow outside the vortex core. With these measurements, the behavior of vortices in the rotor’s wake could be described with generalized semi-empirical models.

Studying the effect of incoming turbulence level on the flow in the blade wake

Studying the effect of incoming turbulence level on the flow in the blade wake

Visual analysis of the impact of periodic wakes on the pressure side of a turbine blade

Turbines are core components in jet engines for flight propulsion, power plants, and other important energy conversion processes. They are composed of successive rows of blades so that wakes of upstream blades reach subsequent blades where they perturb the flow in an unsteady manner. At the point where a wake reaches the downstream blades, the perturbation forms a so-called negative jet. In this work, we show that the negative jet partially fulfills the conditions of an anti-splat. Based on this finding, we enhance an anti-splat detection algorithm developed by the present authors in previous work and apply it to direct numerical simulation data of a turbine cascade with unsteady wakes. This provides a sound framework and suitable visualization approaches to investigate the phenomenon even in very complex conditions, as is the alteration of the boundary layer flow along the pressure side of a turbine blade. The approach allows a very clear visualization of this interaction, which was not possible to evidence with previous methods, providing new insight into the physics of this flow. The use of flow paths shows up to which point wakes affect the boundary layer along the blade. The reported physical analysis, made possible by the proposed approach, demonstrates the usefulness of the method for the application domain. The generalization to flows in compressors, pumps, and blade-tower interaction in wind engineering and other fields is possible.Graphical abstract

Numerical simulations of the wake and deformations of a flexible rotor blade in a turbulent flow

We present, for the first time, the mean deflection evolution of a flexible rotor blade using a coupled model based on Navier–Stokes equations, for the fluid flow, and linear elasticity equations for the blade deformation. Three turbulence models are tested to reach Reynolds numbers as high as 8 104. The absolute tip speed ratios are in the range [0,25]. The numerical results are validated by comparisons with available tip displacements from experiments. For the parameter ranges, above mentioned, the elastic behavior of the flexible rotor is characterized, and the vorticity field is compared with results obtained for a rigid rotor. The effects of the pitch, the tip speed ratio (or frequency), and its sign on the blade deformation are reported. Typically, the blade deforms in the downstream direction, and it is shown that this deformation is a non-monotonic function of the rotation frequency and the pitch angle. Furthermore, it is found that, for particular values of the frequency and pitch angle, the blade is subject to deformations in the upstream direction. It is shown also that the flexible rotor could develop a vortex ring state, but not the rigid one, under the same conditions. It is found that there is a supercritical frequency associated with the apparition of this vortex ring state and this frequency occurs for negative pitches only, for the considered blade. The vorticity field revealed, as well, that the tip vortex changes sign with that of the blade deflection. Finally, we present the effect of the pitch and frequency on the twist angle of the blade and characterize its evolution along the span.

Aerodynamics of inter-spool duct under the influence of an upstream transonic compressor stage

The compressor inter-spool duct (ISD), with its offset and profiled curvature, is an inherent part of the turbofan system due to large density gradients and substantial area changes across each spool. The aerodynamic performance of the ISD is highly dependent on the upstream flow conditions, and hence its design process must account for the upstream effects. In the present investigation, the inter-spool duct design is carried out, suiting an existing high-speed transonic compressor stage, forming an integrated system. The emphasis of this investigation is to assess the effect of upstream secondary flow structure, i.e., shock losses, tip leakage vortices, blade wakes, and corner-separated flow, on the aerodynamic performance of the duct. The compressor stage performance is presented with the help of experimental and numerical data at design and off-design conditions. The inter-spool duct is numerically analyzed considering uniform inlet flow and the flow coming from the upstream high-speed compressor stage. This investigation reveals that the duct with uniform inlet flow is free from any severe flow separation; consequently, minimum loss. However, the losses are observed to increase significantly with the upstream compressor stage. The majority of the losses are incurred at the duct inner wall due to large wake structures emanating from the stator hub section. The stage exit swirl throughout the duct in the outer wall region, in combination with the hub-separated flow, results in the low-pressure region at the duct-inner wall, causing flow reversal at the exit. This creates flow blockage resulting in a decrease in the choke margin of the integrated system. The overall efficiency of the integrated system is also reduced owing to the losses encountered within the duct.

Numerical investigation of h-Darrieus wind turbine aerodynamics at different tip speed ratios

PurposeThe purpose of the paper is to predict the aerodynamic performance of a complete scale model H-Darrieus vertical axis wind turbine (VAWT) with end plates at different operating conditions. This paper aims at understanding the flow physics around a model VAWT for three different tip speed ratios corresponding to three different flow regimes.Design/methodology/approachThis study achieves a first three-dimensional hybrid lattice Boltzmann method/very large eddy simulation (LBM-VLES) model for a complete scaled model VAWT with end plates and mast using the solver PowerFLOW. The power curve predicted from the numerical simulations is compared with the experimental data collected at Erlangen University. This study highlights the complexity of the turbulent flow features that are seen at three different operational regimes of the turbine using instantaneous flow structures, mean velocity, pressure iso-contours, blade loading and skin friction plots.FindingsThe power curve predicted using the LBM-VLES approach and setup provides a good overall match with the experimental power curve, with the peak and drop after the operational point being captured. Variable turbulent flow structures are seen over the azimuthal revolution that depends on the tip speed ratio (TSR). Significant dynamic stall structures are seen in the upwind phase and at the end of the downwind phase of rotation in the deep stall regime. Strong blade wake interactions and turbulent flow structures are seen inside the rotor at higher TSRs.Research limitations/implicationsThe computational cost and time for such high-fidelity simulations using the LBM-VLES remains expensive. Each simulation requires around a week using supercomputing facilities. Further studies need to be performed to improve analytical VAWT models using inputs/calibration from high fidelity simulation databases. As a future work, the impact of turbulent and nonuniform inflow conditions that are more representative of a typical urban environment also needs to be investigated.Practical implicationsThe LBM methodology is shown to be a reliable approach for VAWT power prediction. Dynamic stall and blade wake interactions reduce the aerodynamic performance of a VAWT. An ideal operation close to the peak of the power curve should be favored based on the local wind resource, as this point exhibits a smoother variation of forces improving operational performance. The 3D flow features also exhibit a significant wake asymmetry that could impact the optimal layout of VAWT clusters to increase their power density. The present work also highlights the importance of 3D simulations of the complete model including the support structures such as end plates and mast.Social implicationsAccurate predictions of power performance for Darrieus VAWTs could help in better siting of wind turbines thus improving return of investment and reducing levelized cost of energy. It could promote the development of onsite electricity generation, especially for industrial sites/urban areas and renew interest for VAWT wind farms.Originality/valueA first high-fidelity simulation of a complete VAWT with end plates and supporting structures has been performed using the LBM approach and compared with experimental data. The 3D flow physics has been analyzed at different operating regimes of the turbine. These physical insights and prediction capabilities of this approach could be useful for commercial VAWT manufacturers.