Optimisation of propulsion in human swimming
Aim: Develop a system to visualize the flow around a human swimmer.
Can we go any faster? Swimming is one of the major athletic sports and many efforts are being made to set new records. Usually the biomechanics and the physiology of the athletes are studied by human movement scientists. In this project the human swimmer is studied from a hydrodynamic point of view, by using techniques we are familiar with in the fluid dynamics area. This may lead to new insights and better understanding of the optimal propulsion in swimming.
The main goal of this project, in collaboration with Innosportlab de Tongelreep in Eindhoven and the faculty of human movement sciences in Amsterdam, is to develop a system to visualize the flow around the swimmer in a regular swimming pool. We would like to build a system based on a well-known experimental technique in fluid dynamics. This is rather challenging in this applied situation. For example, we have to deal complex movements of the swimmer and we need quite big field of views in order to follow the flow structures generated by the swimmer. Furthermore, using regular tracer particles and lasers to light up those particles (like we do in the lab) are out of the question. This could be harmful for both swimmer and swimming pool. This is why the idea of air bubble tracers existed. However, bubble tracers are far from ideal. It is studied how the velocity field, obtained with those bubbles, must be interpreted and how reliable those results are. On this basis and with the limitations in mind, decisions can be made about the final experimental set up in the swimming pool and we could start analysing the results obtained with the system.
Picture of a swimmer swimming through a bubble curtain of an old bubble system at Innosportlab. This system has never been in use, was far from ideal and analysing the flow was still impossible.
3D hand simulations were performed in the graduation project by Josje. These simulations fit the purpose of this project and thus it is tried to continue this study.
To involve the swimming world in an earlier stage of this project, some smaller studies related to human movement sciences are performed as well.
Left: External pacing experiment. The swimmers had to synchronize their stroke frequency to the beat on the mp3 player. Right: Picture of the 3D hand simulation performed by the immersed boundary code.
Josje van Houwelingen, Rudie Kunnen, Willem van de Water, GertJan van Heijst, Herman Clercx