Unstructured overset incompressible computational fluid dynamics for unsteady wind turbine simulations

Lynch, C. Eric; Smith, Marilyn J.

doi:10.1002/we.1532

Cited by 31 publications

(9 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“… experienced similar behavior in 2002 also with full turbulent flow on only 1.3 Mio points. Moreover, results of Yelmule and Anjuri or Lynch reveal that transition prediction appears to enable more accurate prediction of the pressure distribution.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Investigation of the NREL phase VI experiment with the incompressible CFD solver THETA

2017

View full text Add to dashboard Cite

DLR's incompressible flow solver THETA is introduced for wind turbine applications on the isolated NREL phase VI Unsteady Aerodynamic Experiment rotor. The optimization of parameter settings for the prediction of attached and separated flows on the rotor is performed, including time step size, spatial discretization scheme, turbulence models and Chimera overset grid technique. Afterwards, a systematic study on the pressure distributions, rotor thrust and rotor torque for experimental series S, I and J is performed. The accuracy of results for wind velocities between 7 and 25 m s 1 , covering attached, partly separated and deep stalled flow conditions, is discussed. While good to excellent agreement between THETA sectional pressure distributions and the experimental reference data is achieved in attached flow and deep stall configurations, more efforts are needed to predict partly separated flow cases with comparable accuracy. A code-to-code comparison with DLR's compressible flow solver TAU enabled the quantification of differences in pressure prediction because of the use of incompressible and compressible flow solvers.

show abstract

Section: Resultsmentioning

confidence: 99%

“…, Rahimi et al. or Lynch and Smith who use EllipSys3D, OpenFoam or FUN3D, respectively. Even though the latter two codes contain compressible and incompressible formulation , the authors do not investigate the validity of the incompressible assumption.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the NREL phase VI experiment with the incompressible CFD solver THETA

2017

View full text Add to dashboard Cite

show abstract

“…Lynch and Smith [11] experimentally studied the unstructured over set incompressible CFD simulations of wind turbine using a hybrid RANS/LES turbulence model. A correlated model was predicted.…”

Section: Introductionmentioning

confidence: 99%

The aerodynamics of the wavy blade under the effect of fluctuated wind flow

Al-Bakri¹,

Aljuhashy²

2021

FME Transactions

View full text Add to dashboard Cite

In the present study, the influence of the wavy edge blade on aerodynamic characteristics for the flow of blades at Reynolds number (Re) of 8×105 is numerically investigated based on the unsteady wind flow. Aerodynamic characteristics of a (sinusoidal leading edge) wavy NACA0015 aerofoil blade are carried out using ICEM 19.1 and ANSYS fluent. The numerical simulation is conducted then validated by experimental data with steady wind flow. This is conducted by employing the same Reynold's number in the experimental work. While, the unsteady flow was numerically performed at 1 Hz frequency of wind flow conditions. The main findings from this work show that the wavy blade can behave better in turbulent wind conditions with the maximum lift coefficient of 0.73 compared to 0.621 for the normal blade. However, the findings declare that the wavy blade stalled earlier than the normal one in the unsteady flow case. Similarly, it stalled at 12° angle of attack earlier than the normal one which was stalled at 14° in the steady flow case.

show abstract

“…As such, the RANS approach currently falls short in precisely predicting the shaft torque at stall, as laminar/turbulent boundary layer transition and flow separation have both been shown to have first-order effects on blade aerodynamics predictions [5]. Full-scale computational fluid dynamics (CFD) studies have shown that increasing RANS fidelity for separated flows and wake regions by employing detached-eddy simulation (DES) can significantly improve predictions of blade torque near stall compared with RANS [6][7][8], and the application of the hybrid RANS/LES model yielded nearly identical solutions compared with RANS at low wind speed.…”

Section: Introductionmentioning

confidence: 99%

Hybrid RANS/LES Turbulence Model Applied to a Transitional Unsteady Boundary Layer on Wind Turbine Airfoil

Zhang

Cadel

Paterson

et al. 2019

Fluids

View full text Add to dashboard Cite

A hybrid Reynolds-averaged Navier Stokes/large-eddy simulation (RANS/LES) turbulence model integrated with a transition formulation is developed and tested on a surrogate model problem through a joint experimental and computational fluid dynamic approach. The model problem consists of a circular cylinder for generating coherent unsteadiness and a downstream airfoil in the cylinder wake. The cylinder flow is subcritical, with a Reynolds number of 64,000 based upon the cylinder diameter. The quantitative dynamics of vortex shedding and Reynolds stresses in the cylinder near wake are well captured, owing to the turbulence-resolving large eddy simulation mode that was activated in the wake. The hybrid model switched between RANS and LES modes outside the boundary layers, as expected. According to the experimental and simulation results, the airfoil encountered local flow angle variations up to ±50°. Further analysis through a phase-averaging technique found phase lags in the airfoil boundary layer along the chordwise locations, and both the phase-averaged and mean velocity profiles collapsed into the Law-of-the-wall in the range of 0 < y + < 50 . The features of high blade-loading fluctuations due to unsteadiness and transitional boundary layers are of interest in the aerodynamic studies of full-scale wind turbine blades, making the current model problem a comprehensive benchmark case for future model development and validation.

show abstract

Unstructured overset incompressible computational fluid dynamics for unsteady wind turbine simulations

Cited by 31 publications

References 48 publications

Investigation of the NREL phase VI experiment with the incompressible CFD solver THETA

Investigation of the NREL phase VI experiment with the incompressible CFD solver THETA

The aerodynamics of the wavy blade under the effect of fluctuated wind flow

Hybrid RANS/LES Turbulence Model Applied to a Transitional Unsteady Boundary Layer on Wind Turbine Airfoil

Contact Info

Product

Resources

About