Establishing computational fluid dynamics models for swimming technique assessment

This thesis set out to create a three dimensional active computational fluid dynamics model capable of assessing swimming techniques and enhancing an understanding of the assessment capabilities of the model in practice. Over the past century, numerous studies have measured the passive and active drag of swimmers. Passive drag usually refers to the combination of pressure and viscous forces on a rigid body moving at a constant velocity through water. Active drag is usually described as the combined pressure and viscous forces acting on a swimming body travelling at constant or varying velocities through water. Due to the complexities in measuring active drag, the range of techniques used have not provided any definitive conclusions regarding the accuracy of any single measurement technique over another. More recently, an increased use of mathematical modelling has sought to improve estimates and understanding of active drag. One such method is to use Computational Fluid Dynamics (CFD), but to date simulations mostly have considered passive drag and quasi-static studies using isolated segments. This project focused on extending the technology by providing a full CFD simulation of the entire human body during a normal swimming stroke. It was completed via the following steps: 1. Setting up and validating a passive drag simulation of an elite swimmer. 2. Developing a mathematical algorithm for controlling the movements of the three dimensional model within the CFD environment. 3. Subsequently, using the above models to simulate increasingly complex movements in the sequence of: Dolphin kick underwater. Freestyle kick underwater. Freestyle kick near the water surface. Breaststroke kick underwater. Full freestyle stroke. A CFD model capable of all these steps was developed and the model validations revealed sufficient accuracies when analysing changes in active drag during swimming.