UNAFLOW project: UNsteady Aerodynamics of FLOating Wind turbines

UNAFLOW (UNsteady Aerodynamics for Floating Wind) is a joint EU-IRPWIND founded experiment on wind turbine rotor unsteady aerodynamics. It brings together four different academic contributors: Energy research Centre of the Netherlands (ECN), DTU Wind Energy, University of Stuttgart (USTUTT) and Politecnico di Milano (PoliMi) sharing knowledge both in numerical modelling and in experimental tests design, allowing direct numerical and experimental comparison. The experimental tests carried out for UNAFLOW are of the same type of the ones carried out during the ongoing EU H2020 project LIFES50+ [1], regarding both the unsteady behaviour of the 2d blade section and the entire turbine rotor, although with improved setup and wider test matrix. The project partners are already currently jointly collaborating in the AVATAR project [2], developing and validating numerical models of different accuracy level. The numerical models used in the UNALFOW project range from engineering tool (eg. BEM) to high fidelity CFD methods. Numerical simulations are used both in the design of experiment phase and in the results analysis allowing for an in depth understanding of the experimental findings through advanced modelling approach. The UNAFLOW project, together with a new understanding of the unsteady behaviour of the turbine rotor aerodynamics, will provide also an open database to be shared among the scientific community for future analysis and new models validation

On the aero-elastic design of the DTU 10MW wind turbine blade for the LIFES50+ wind tunnel scale model

This paper illustrates the aero-elastic optimal design, the realization and the verification of the wind tunnel scale model blades for the DTU 10 MW wind turbine model, within LIFES50+ project. The aerodynamic design was focused on the minimization of the difference, in terms of thrust coefficient, with respect to the full scale reference. From the Selig low Reynolds database airfoils, the SD7032 was chosen for this purpose and a proper constant section wing was tested at DTU red wind tunnel, providing force and distributed pressure coefficients for the design, in the Reynolds range 30-250 E3 and for different angles of attack. The aero-elastic design algorithm was set to define the optimal spanwise thickness over chord ratio (t/c), the chord length and the twist to match the first flapwise scaled natural frequency. An aluminium mould for the carbon fibre was CNC manufactured based on B-Splines CAD definition of the external geometry. Then the wind tunnel tests at Politecnico di Milano confirmed successful design and manufacturing approaches

Project management between will and representation

This article challenges some deep-rooted assumptions of project management. Inspired by the work of the German philosopher, Arthur Schopenhauer, it calls for looking at projects through two complementary lenses: one that accounts for cognitive and representational aspects and one that accounts for material and volitional aspects. Understanding the many ways in which these aspects transpire and interact in projects sheds new light on project organizations, as imperfect and fragile representations that chase a shifting nexus of intractable human, social, technical, and material processes. This, in turn, can bring about a new grasp of notions such as value,\ud knowledge, complexity, and risk

Recent snow cover variations and avalanche activities in the Southern Alps

Snow and albedo play a significant role in the planet's radiation balance. Snow cover extension, of the Northern Hemisphere in the last forty years, generally decreased causing direct and indirect feedback both on climate and atmospheric circulation. Up-to-date available data on seasonal snow cover trend are scarce and limited to few nations. Few European studies in the Northern Alps highlighted a decrease in snow cover duration and an increase of its elevation for tourism purposes. Using the data of more than 60 sites located in the Southern Alps a first budget of the recent snow cover trend has been outlined. Compared to the 1961-90 mean value, the average snow cover duration decreased of about 14 days, with a major influence on elevations lower than 1600 metres. Seasonal snow precipitation accumulation has been decreasing, at all elevations, since 1990. Winter 2008-2009 was the 3rd or 4th more snowy season since 1930. During this winter spontaneous avalanche activity was frequent and extreme avalanches often detached. The 2008-2009 winter daily observation data of several sites located in the Southern Alps were used to find interconnections between recent snow cover variations, spontaneous avalanche activity and avalanche accidents