Transpiration flow is a very important and still open subject in many technical applications. Perforated walls are useful for the purpose of “flow control”, as well as for the cooling of walls and blades (effusive cooling) in gas turbines. We are still not able to include large numbers of holes in the numerical calculations and therefore we need physical models. Problems are related also to the quality of the holes in perforated plates. The present transpiration analysis concerns with experimental investigations of the air flow through perforated plates with microholes of 125 and 300 µm diameters. A good accordance of the results with other experiments, simulations and theory was obtained. The received results very clearly show that technology manufacturing of plate holes influences on their aerodynamic characteristics. It turned out that the quality of the plate microholes using laser technology and, consequently, the shape of the hole, can affect the flow losses. Therefore, this effect was investigated and the flow characteristics in both directions were measured, i.e., for two plate settings.

In this project, an innovative wind turbine was designed for a floating plant. A large Savonius rotor was replaced with a double-rotor wind turbine implemented as a horizontal-axis turbine. This double rotor was positioned on the tip of a thrust plate and fixed to the deck of a catamaran. Simple 2D numerical simulations were performed to confirm the effectiveness of the concept. An analysis of the floating system configuration was carried out, and the loads and stresses on the system components were verified. Next, floating supports with appropriate sizes were selected to counteract the forces on the wind turbine system. Finally, an anchoring system with full rotational freedom was selected for the floating platform. The present work was conducted as part of a Master’s thesis.

Savonius wind turbines are gaining attention for their low-maintenance design and suitability for small-scale distributed power generation. The THRUST (The High Rotational Urban Savonius Turbine) project focuses on a small diameter Savonius rotor designed to withstand high wind speeds without a braking system. The experimental investigation was conducted in the Giovanni Solari Wind Tunnel at the University of Genoa, under smooth and turbulent flow. In addition to assessing flow conditions, key performance parameters such as torque, voltage, current, rotational speed, and rotor-generated noise were measured in the wind tunnel. Further investigations, including CFD simulations, have allowed to explore these effects in more detail and to interpret the rate of effective wind velocity increase caused by the wind tunnel blockage due to the presence of the wind turbine. This paper outlines the activities conducted, providing the description of the model, experiments, and measurements. As an example, a selection of results is presented, including power and torque curves, as well as acoustic emission measurements recorded near the rotor. The findings indicate that the Savonius rotor can sustain energy generation even at high wind speeds and turbulence, making it a viable solution for wind energy production in challenging conditions.

An experimental investigation was carried out to study the turbulent flow behind passive grids in a subsonic wind tunnel. The enhanced level of turbulence was generated by five wicker metal grids with square meshes and different parameters (diameter of the grid rod d = 0.3 to 3 mm and the grid mesh size M = 1 to 30 mm). The velocity of the flow was measured by means of a one-dimensional hot-wire probe. For this purpose, skewness, kurtosis, and transverse variation of the velocity fluctuations were determined, obtaining knowledge of the degree of turbulence isotropy and homogeneity in the flow behind grids of variable geometry, for different incoming velocities U = 4, 6, 10, 15, 20 m/s. Approximately, the isotropic and homogeneous turbulence was obtained for x/M > 30. Next, several correlations for turbulence degeneration law were tested. Finally, as the main goal of the study, impact of turbulence intensity on bypass laminar–turbulent transition parameters (transition inception, shape parameter, and the length of the transition region) on a flat plate was investigated. Parameter ITu_m was created as an integral taken from the leading edge of the plate to the transition inception, divided by the distance from the leading edge to the transition inception, expressing in this way the averaged value of turbulence intensity.