Victor Mendoza
Uppsala University
Born in Arica, Chile Mechanical Engineer - University of Tarapaca (Chile)Msc in Energy: Production, Management and Efficiency use - University of Valladolid (Spain) PhD Candidate "Aerodynamic Studies of Vertical Axis Wind Turbines using the Actuator Line Model" - Uppsala University (Sweden)
Numerical and experimental results are essential tools in order to understand the resulting flow pattern of operating wind turbines, and therefore, in the design for maximum loads on the components and the spacing arrangement... [ view full abstract ]
Numerical and experimental results are essential tools in order to understand the resulting flow pattern of operating wind turbines, and therefore, in the design for maximum loads on the components and the spacing arrangement in wind farms.
Due to the complexity of the flow phenomena involved in the aerodynamics of both horizontal and vertical axis wind turbines, several and well known experimental activities have been carried out on open sites and wind tunnel facilities for identifying the relevant parameters of the flow involved and the performance of the tested devices.
For the studies in wind tunnel facilities, for avoiding the blockage effect of a confined tunnel, it is a common practice to have an incoming flow from an open jet at the inlet. However, an open jet itself is characterized by a flow with an abrupt expansion and recirculation zones (in the regions close to the corners of the test chamber), which can considerably influence the obtained results from the turbine.
In the present work, simulated blade loads and the resulting wake from an operating vertical axis wind turbine are studied using an actuator line model. The Open Jet Facility at Delft TU experimental work (G.Tescione et al. - 2014) is used as a reference case, together with a simulation where the open jet is replaced by a uniform flow over the whole section.
The obtained results show a difference in the wake structure (size, shape and location) and blade forces when replacing the open jet. Figures 1 and 2 depict that the lateral and vertical wake expansion is reduced by the incoming uniform flow. Figure 3 reveals that the wake breaks earlier in the case with an open jet. Additionally, there is a dissipation of energy due to the expansion of the flow and the recirculation zones, and therefore, a reduction on the forces acting on the blades.
Generally, there is a considerable difference on the obtained results between using an open jet at the inlet of the test chamber and a uniform flow.
