Spatial study of the wake meandering using modelled wind turbines in a wind tunnel

International audienceThe wind turbine is modelled at a geometric scale of 1:400 with a static porous disk (actuator disk concept). The main objective of the present work was to supply quantitative information on the meandering process. The instantaneous wake width and its horizontal and vertical swerves from the mean wake axis are quantified using specific image processing of instantaneous velocity fields obtained by particle image velocimetry downstream of the modelled wind turbine. We observe that the wind turbine wake displacements from the mean streamwise axis are very important when the turbulence length scales are larger than the wake width. We also observe that, in ABL conditions, horizontal displacements are higher than the vertical ones with a proportion in agreement with the ratio between the transverse and vertical turbulence intensities σv∕σw ≈ 3∕2. It is finally concluded that the instantaneous wake width remained nearly constant downstream of the wind turbine model whatever the flow conditions and that the extent of the mean wind turbine wake is dominantly due to the meandering process. This confirms that it is necessary to include the meandering process in the wake analysis in order to estimate the fatigue loading on wind turbines within wind farms properl

Recent developments in hardware-in-the-loop testing

Future applications of mechatronic systems will be characterized by a high degree of digitization enabling the integration of numerous innovative functions. The validation and reliability analysis of such complex systems often requires the realization of cost intensive full system prototypes and the evaluation of field tests. Innovative technologies are therefore integrated slowly in industrial sectors that focus on system reliability. Hence, there is a strong interest in a reliability orientated development and test process for complex mechatronic systems.The integration of real-time simulations in test environments allows efficient development and verification of the individual components of a mechatronic system in many cases. Currently, this especially applies for the test-driven development of embedded control units and their corresponding software. A reduced number of field tests, the automated run of test procedures and the application of error injection methods can be achieved by the widely used Hardware-in-the-Loop (HIL) technique. In signal level HIL tests, an existing control unit is connected to a virtual real-time simulation of the residual system. If however the device under test includes a mechanical or power electrical interface, the coupling of the test object to a virtual residual system requires the application of a mechanical or power electrical HIL interface. Current activities aim for this extension of In-the-Loop technologies for the validation of mechanical and power electronic subsystems.This paper highlights the potential of combined signal level, mechanical level and power electrical HIL tests for the validation of complex mechatronic systems in an early phase of design. The paper also points out the key topics of test-driven development, real-time simulation and the realization of hybrid test environments by means of mechanical and power electrical HIL interfaces