Effects of miniature filament on flow characteristics

• Main Author: Cheng, Marcus Xin Jun
• Other Authors: Chan Weng Kong
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2020
• Subjects: Engineering::Mechanical engineering::Fluid mechanics
• Online Access: https://hdl.handle.net/10356/140989
• Institution: Nanyang Technological University

The aerodynamic properties and amount of drag experienced by athletes is highly dependent on the surface morphology of the fabrics. The use of appropriate types of fabrics, coupled with optimal stitch orientation and stretch level, can yield aerodynamically advantageous designs of sports apparels as surface morphology are largely relies on these factors. In this study of fabrics, six types of fabrics with different compositions, stitch orientation and various stretch condition were tested using the cylindrical methodology in the wind tunnel over a range of Reynolds number. The results were analysed and compared with the surface roughness of these fabric samples measured for each sample, as well as the microscopic images of the surface morphology. The study concluded that the variations in fabric composition, stitch orientations and elongations had observable effects on the surface roughness of the fabrics, resulting in different aerodynamic properties. The analysis indicated that, the minimum drag coefficient is lower, and reduction in drag coefficient from low to high speed occurs earlier for stretched fabrics as compared to the unstretched condition. It is also suggested that fabrics with stitch oriented at 90° displayed better flow properties than samples at 0° orientation. The lowest drag coefficient was obtained using 25% spandex composition, oriented at 90° with a 25% stretch elongation. Furthermore, the experimental results provided recommendations on suitable fabrics to be used for sports at different speed range.