Session: 41-05 Small, vertical and new concept turbines

Submission Number: 178560

Fluorescein Flow Visualization and CFD Simulation of a Hydrokinetic Turbine Model 

Characterising the flow around hydrokinetic turbines is essential for understanding the formation of wakes, recirculation, and vortex shedding, which directly affect the hydraulic performance, blade life, and environmental interactions of these devices. However, conventional experimental flow-visualisation methods, such as PIV or LDA, require expensive equipment and specialised laboratory conditions, posing an economic barrier that is not easy to overcome. This article presents the development of a low-cost, easy-to-implement visualisation system designed for the qualitative identification of flow structures in hydrokinetic turbine configurations. The proposed system aims to facilitate the validation of CFD simulations, support applied research, and serve as a training tool for studying fluid dynamics in renewable energy applications.

The use of tracers such as sodium fluorescein provides an economical and accessible means of visualising flow behaviour around hydrokinetic turbines. The system described employs this element as a hydrodynamic tracer, together with ultraviolet illumination, to reveal the evolution of streamlines as they interact with the turbine blades. Wakes and vortices that generate energy losses by increasing induced drag are detected, supporting designs that minimise shedding and recirculation to improve the turbine’s power coefficient. Regions of low pressure, where cavitation may occur, are also identified, helping to prevent structural damage and performance loss. This approach allows for a more detailed analysis of vortex shedding, which produces fluctuating stresses leading to vibrations, fatigue, and noise. Reducing these effects prolongs the service life of the blades and the turbine as a whole. Furthermore, understanding vortex dynamics contributes to the development of more “fish-friendly” blade profiles by reducing sudden pressure gradients and enhancing environmental compatibility.

Preliminary tests, carried out using high-resolution imaging, have made it possible to identify all these phenomena at a significantly lower cost than traditional techniques. The results demonstrate the system’s potential as a qualitative tool for analysing flow dynamics and support its future integration with computational fluid dynamics (CFD) models.

Presenting Author: Ahmed Gharib Yosry University of Oviedo

Presenting Author Biography: Dr. Ahmed Yosry is a lecturer and researcher in fluid dynamics and renewable energy systems.He received his Ph.D. degree in 2023 from the Department of Energy at the University ofOviedo, Spain. He obtained a dual master degree in 2017 from the University of Oviedo andPort Said University under the Erasmus Mundus programme. His research interests includerenewable energy, sustainability, fluid dynamics, the design and experimental testing of windand hydrokinetic turbines, and CFD simulations using ANSYS and OpenFOAM.

Authors:

Rodolfo Espina-Valdés University of Oviedo
Ahmed Gharib Yosry University of Oviedo
Aitor Fernández-Jiménez University of Oviedo
Álvaro García-Martínez University of Oviedo
Eduardo Álvarez-Álvarez University of Oviedo