Computational fluid dynamics analysis of the wake behind the MEXICO rotor in axial flow conditions

Abstract

This paper presents a computational investigation of the wake of the MEXICO rotor. The compressible multi-block solver of Liverpool University was employed, using a low-Mach scheme to account for the low-speed flow near the blade and in the wake. In this study, computations at wind speeds of 10, 15 and 24 m s 1 were performed, and the three components of the velocity were compared against experimental data around the rotor blade up to one and a half rotor diameters downstream. Overall, fair agreement was obtained with the computational fluid dynamics showing good vortex conservation near the blade. Vorticity values revealed discontinuities in the wake at approximately 70%R, where two different aerofoils with different zero-lift angles are blended. The results suggest that all-Mach schemes for compressible computational fluid dynamics methods can deliver good performance and accuracy over all wind speeds for flows around wind turbines, without the need to switch between incompressible and compressible flow methods.

Near wake analysis of actuator line method immersed in turbulent flow using large-eddy simulations

“…The Gaussian This would necessitate a resolution of N ≥ 4096 for the here presented case which would result in a computational grid beyond any justifiable computational scope. Full rotor calculations as conducted by Carrión et al (2015) allowed to obtain tip vortices of r core /R ≈ 0.012 for N ≈ 900 in the tip region which corresponds very well to results in Figure (10). Another result for the vortex radius can be found in Nilsson et al (2015) where for /∆x = 1 and N ≈ 244 in the tip region a vortex core 10 radius of r core /R ≈ 0.055 was found.…”

“…Despite following well the trend of the experimental values the method seems to converge towards radial profiles which are especially off in the tip and hub region where the strongest vortices are shed. These are limitations intrinsic of the ALM which is less apparent when using high fidelity approaches such as full rotor simulations 15 (Carrión et al, 2015).…”

Wind-Turbine Wake Encounter by Light Aircraft

“…Recently, full CFD methods [15,16] were used to study the wake development and breakdown on a three-bladed rotor model of 4.5 m diameter. This rotor model was used in the MEXICO project [17], where blade surface pressure and wake velocity measurements with particle image velocimetry (PIV) were carried out in the DNW wind tunnel.…”

Demonstration of a coupled floating offshore wind turbine analysis with high-fidelity methods

“…The pressure and PIV data of the MEXICO project (Carrión et al (2014)) have also been used for validation, where the wake was resolved on a fine mesh capable to capture and preserve the vortices downstream the rotor (Figure 2b), which enabled the prediction of the onset of wake instabilities (Carrión et al (2015)). …”