Toward Development of a Stochastic Wake Model: Validation Using LES and Turbine Loads

Moon, Jae Sang; Manuel, Lance; Churchfield, Matthew J.; Lee, S.; Veers, Paul S.

doi:10.3390/en11010053

Cited by 5 publications

(2 citation statements)

References 28 publications

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“…Archer et al [16] used LES and an actuator-line model to quantify the effects of array layout on the performance of offshore wind farms. Moon et al [17] used the above numerical approach to generate wake profiles of wind turbines. The wake-related mean and turbulence field were then estimated to develop a stochastic wake model for farm design.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of shallow-water effects on hydrokinetic turbine wake recovery

O'Doherty¹,

Thompson²,

Bhushan³

et al. 2020

Int. J. Mar. Ene.

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Thrust, power and intermediate wake predictions obtained using resolved rotating blade with sliding mesh simulations for a hydrokinetic turbine (HKT) are assessed using the open-source flow solver OpenFOAM. Single- and two-phase URANS and DES computations are performed for three-blade, 0.5m diameter (D) turbine mounted on a stanchion that intersects the free surface with a tip-speed ratio λ = 6.15. The thrust and power predictions compare within 5% of the experimental data. Results show that the thrust predictions are dominated by the pressure distribution on the blades, whereas the shear stress plays a significant role in the power predictions. The turbine performance showed unsteadiness with amplitudes around 3% of the mean, due to the disruption of the flow each time a blade passed in front of the stanchion. The wake recovery is primarily due to the growth of shear layers (originating from the blade tips) towards the turbine axis, which are primarily caused by the cross-plane turbulent velocity. The shear layer growth is enhanced by the turbulence produced by the stanchion. Predictions of the mean wake profile compared within 10% of the experimental data, which is significant improvement over previous Fluent predictions that showed large errors of 22%. The improved predictions in OpenFOAM is attributed to better turbulence predictions. Two-phase results show that the interaction between the wake and free-surface is initiated by the interaction of stanchion with the free-surface. The free-surface creates a blockage effect that accelerates the flow in the upper bypass region and enhances the wake recovery.

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Section: Introductionmentioning

confidence: 99%

Numerical investigation of shallow-water effects on hydrokinetic turbine wake recovery

O'Doherty¹,

Thompson²,

Bhushan³

et al. 2020

Int. J. Mar. Ene.

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show abstract

“…A feasible option is to use wall-modeled LES approach where the viscous sub-layer and the buffer region of the boundary layer are modeled instead of being resolved, substantially reducing the stringent grid requirements. Few studies have utilized WMLES for the numerical analysis of compressors [23][24][25] and turbines [26][27][28]. These studies have focused on the development of accurate physics based modeling tools for predictive design in complex geometries.…”

Section: Introductionmentioning

confidence: 99%

Massively Parallel Large Eddy Simulation of Rotating Turbomachinery for Variable Speed Gas Turbine Engine Operation

et al. 2020

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Gas turbine engines are required to operate at both design and off-design conditions that can lead to strongly unsteady flow-fields and aerodynamic losses severely impacting performance. Addressing this problem requires effective use of computational fluid dynamics tools and emerging models that resolve the large scale fields in detail while accurately modeling the under-resolved scale dynamics. The objective of the current study is to conduct massively parallel large eddy simulations (LES) of rotating turbomachinery that handle the near-wall dynamics using accurate wall models at relevant operating conditions. The finite volume compressible CharLES solver was employed to conduct the simulations over moving grids generated through Voronoi-based unstructured cells. A grid sensitivity analysis was carried out first to establish reliable parameters and assess the quality of the results. LES simulations were then conducted to understand the impact of blade tip clearance and operating conditions on the stage performance. Variations in tip clearance of 3% and 16% chord were considered in the analysis. Other design points included operation at 100% rotor speed and off-design conditions at 75% and 50% of the rotor speed. The simulation results showed that the adiabatic efficiency improves dramatically with reduction in tip gap due to the decrease in tip leakage flow and the resulting flow structures. The analysis also showed that the internal flow becomes highly unsteady, undergoing massive separation, as the rotor speed deviates from the design point. This study demonstrates the capability of the framework to simulate highly turbulent unsteady flows in a rotating turbomachinery environment. The results provide much needed insight and massive data to investigate novel design concepts for the US Army Future Vertical Lift program.

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An improved dynamic model for wind-turbine wake flow

Feng,

Gupta,

et al. 2024

Energy

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Toward Development of a Stochastic Wake Model: Validation Using LES and Turbine Loads

Cited by 5 publications

References 28 publications

Numerical investigation of shallow-water effects on hydrokinetic turbine wake recovery

Numerical investigation of shallow-water effects on hydrokinetic turbine wake recovery

Massively Parallel Large Eddy Simulation of Rotating Turbomachinery for Variable Speed Gas Turbine Engine Operation

An improved dynamic model for wind-turbine wake flow

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