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- 2025-2027. strengthening of the scientific and technological capacities in aerodynamics, FONDEQUIP EQM240006. Coordinator.
About the project: Acquisition of an open-circuit wind tunnel with a test section of 0.5m × 0.5m × 1.5m and wind speed of up to 50m/s. The tunnel is equipped with control instrumentation that allows the setting of the operating speed and the monitoring of the air’s physical conditions. Additionally, the main section of the tunnel has optical access and includes accessories for advanced testing, such as a three-axis balancer (measuring forces and moments) and a wake probe system.
- 2024-2026. Flow control devices for small wind turbine technologies, DIUFRO 240036. Principal Investigator.
About the project: It is the goal of this project to prototype suitable retrofits to enhance the power output of small wind turbines (SWT). These retrofits are small passive devices that can be integrated over blades to boost aerodynamic efficiency i.e., producing more power under the same conditions. The chosen devices are protuberances, vortex generators and Gurney flaps. These devices have shown good results over large commercial wind turbines; however, the characteristics of where a SWT operates differ drastically from a conventional one in such rotor height, turbulence, and ramp-up, to name a few and therefore, it is necessary to assess their integration carefully.
- 2021-2023. Offshore Code Comparison, Collaboration, Continued, with Correlation and unCertainty (OC6). Researcher.
About the project: The OC6 project is an international research project run under the International Energy Agency Wind Technology Collaboration Program (IEA Wind) Task 30. The project is focused on validating the tools used to design offshore wind systems. OC6 implements a three-way validation process that compares both the engineering-level modeling tools and higher-fidelity tools to measurement data. The results will be used to help inform the improvement of engineering-level models, and/or guide the development of future test campaigns.
Related publications:
About the project: The project PAK 780, funded by the German Science Foundation (DFG), focused on studying wind turbine load control under realistic turbulent inflow conditions. The Technische Universität Berlin developed a scaled wind turbine model, the Berlin Research Turbine (BeRT), in this framework. BeRT is a research horizontal axis wind turbine with three modular exchangeable blades. The large closed-loop wind tunnel of the Hermann Föttinger Institute (GroWiKa, from the German acronym) was adapted to locate BeRT in a new test section since the standard test section was too small to hold a rotor of 3m diameter. Thus, the settling chamber was extended to reach a total length of approximately 8m. In this way, BeRT is placed in the center of the section to provide the best space compromise between the wind tunnel contraction and the turbulence grids.
Related publications:
- 2017-2022. Local flow characterization of a wind turbine model in a wind tunnel. Principal Investigator.
About the project: The characterization of the flow around a rotor blade is one of the major topics of research in the wind energy field. In particular, the incident flow determines the performance of the blade. Furthermore, the flow downstream of the rotor is important to assess the turbine performance and wake development. This Thesis examines the flow of a wind turbine model in a wind tunnel by characterizing one specific section and the tip of its rotor blade. Experiments are conducted in order to assess different methodologies and parameters of the study. The wind tunnel facility of the Hermann Föttinger Institut at the Technische Universität Berlin is used. The research turbine model is a three-bladed upwind horizontal axis wind turbine model with a rotor diameter of 3m. Additionally, analytical and numerical simulations complement the information from the experiments.
On the one side, the flow on the blade is assessed by determining the local angle of attack at one specific chordwise blade section. Experimental approaches, i.e. three-hole probes and surface pressure taps, are compared to the results of an analytical method. The pressure-based approach includes an application of a two-dimensional methodology extended into a three-dimensional framework. Results show that the pressure tap method is suitable and provides accurate angle of attack estimations, comparable to the external probe measurements as well as the analytical calculations in terms of several operational conditions. This is a significant step for the experimental determination of the local angle of attack due to fewer requirements and potential applications.
On the other side, the flow at the blade tip is evaluated by means of the tip vortices shedding. Phase-locked stereo particle image velocimetry measurements are carried out. Blade tip vortex locations as well as their convection velocity, core radius, and strength are investigated. The results are compared with similar wind tunnel investigations and simulations in the absence of the walls. The focus then is on getting insights into the wind tunnel constraints. Moreover, data are used to perform an in-depth investigation of vortex identification methods and related schemes. In this way, it is shown that both the wind tunnel confinement and the applied identification methodology are pivotal to ensuring robust results.
This research was under the dissertation work to fulfill the degree of Doktor der Ingenieurwissenschaften (Dr.-Ing.) and partially funded by: (i) ANID PFCHA/Becas Chile-DAAD/2016 - 91645539 and (ii) Center for Junior Scholars (CJS) at the Technische Universität Berlin.
Dissertation:
- 2014-2016. Wind energy conversion using induced vibrations. Principal Investigator.
About the project: Energy harvesting is the conversion of energy present in the environment to electrical energy. Within this classification, wind energy can be captured from different sources: natural, such as airflow in free fields; pseudo-artificial, such as air currents in urban environments; such as transportation tunnels, highways, and ventilation ducts. The main objective of this Thesis work is to study the capturable power due to the fluid-structure interaction of an arrangement of two circular, straight, and parallel cylinders, faced with an airflow perpendicular to its axis. The influence of separations, sizes, and attack speed on a wind energy harvesting device, using wake galloping type vibrations, is studied.
A computational analysis of vibrations induced by vortices for the laminar regime is carried out in the ANSYS Fluent 14.5 program and a numerical implementation of fluid-structure interaction is carried out in the FORTRAN program to characterize the flow and movements of a vortex generator. Subsequently, an experimental setup is built in the wind tunnel of the Process Laboratory of the Department of Mechanical Engineering of the Universidad de Chile to analyze the acceleration and power in a wake galloping arrangement. The device consists of two aligned cylinders, with diameters D1 and D2, at a distance L between their centers. The size ratio, Y = D2/D1, and distance ratio, X = L/D1, are studied for wind speeds in the range 1 − 7[ms−1].
The experimental results show that the acceleration has a relationship directly proportional to the square of the wind speed and a maximum RMS power of 4.5[mW], under a configuration of size Y = 0.7 and distance X = 3, achieved under the coupling of the natural frequency and the frequency of vortex shedding on the downstream cylinder. Against mismatched frequencies, the highest performance occurs for a size ratio Y = 1.5 and distance X = 4 with an RMS power range of 0.1 − 0.4[mW]. The power generated can be easily increased by considering, for all reasons of size and distance, exciting the system to its resonance by varying the natural frequency of the system, for example, by modifying its stiffness.
This research was under the thesis work to fulfill the degree of Master in Engineering Science (M.Sc. m/mechanic) and partially funded by CONICYT-PCHA/MagísterNacional/2014 -22140744.
Thesis:
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