Construction of drag force measuring system to characterize the hydrodynamics properties of swimsuit fabrics

Abstract

In this study, a system was designed and constructed in order to measure the drag force acting on the swimmer simulator. This system must be able to obtain the drag force for a range of swimsuit fabrics to characterize the hydrodynamic properties of swimsuit fabric. In this system, a DC motor was used as the propelling unit; also a voltmeter and an ammeter were applied to measure the input power of motor. To find the relationship between input powers and drag force, calibration was done. The simulator was made from wood in two different sizes. The samples of fabrics were prepared from three kinds of weft knitted fabrics, which are common in production of swimsuits, and were knitted from polyamide6 (nylon), polyamide6-elastan (nylon-lycra) and polyester. The statistical analysis of results show the importance of fabric surface properties and swimsuit design on swimmer's performance, so clothing engineering and technical clothing design can play a key role in sport engineering.

High-Speed Swimsuits and Their Historical Development in Competitive Swimming

“…The historical background revealed a great concern with reducing drag by using the most appropriate swimsuit for the period (Foster et al, 2012;Hagedorn, 2013) and for the material (Matsunami and Taimura, 2008;Abasi et al, 2013;Issurin et al, 2014), to bring about a significant improvement thanks to technological innovations (Mountjoy et al, 2009). Since the 1930s a variety of studies had been carried out, mostly with triathletes (Parsons and Day, 1986;Sharp and Costill, 1989;Toussaint et al, 1989;Cordain and Kopriva, 1991;Chatard et al, 1995;Starling et al, 1995;Trappe et al, 1995), in which the conclusions were a long way from extrapolated to the competitive swimming of the time, before FINA approved the use of high-speed swimsuits in 1999, also known as technological or modified swimsuits (Craik, 2011;Foster et al, 2012).…”

“…Brands have also produced different models (Matsunami and Taimura, 2008) and used different materials that have improved hydrodynamics (Moria et al, 2010;Wada et al, 2010;Foster et al, 2012), flotation (Förch et al, 2009;Mountjoy et al, 2009;Wada et al, 2010;Hagedorn, 2013), competitive results (Berthelot et al, 2010;Neiva et al, 2011;O'Connor and Vozenilek, 2011;Abasi et al, 2013;Cortesi et al, 2014) and have reduced active and passive drag (Pendergast et al, 2006;Smith et al, 2007), even adapting models to swimming style (Issurin et al, 2014). However, for the scientific community, materials have not played a determining role in reducing drag (Benjanuvatra et al, 2002;Toussaint et al, 2002;Chatard and Wilson, 2003;Roberts et al, 2003;Moria et al, 2011b).…”

“…However, for the scientific community, materials have not played a determining role in reducing drag (Benjanuvatra et al, 2002;Toussaint et al, 2002;Chatard and Wilson, 2003;Roberts et al, 2003;Moria et al, 2011b). The vast majority of studies have not taken swimsuit design into account when extrapolating their results (Benjanuvatra et al, 2002;Mollendorf et al, 2004;Moria et al, 2010Moria et al, , 2011cAbasi et al, 2013;Issurin et al, 2014), as to date it has not been possible to prove a reduction in drag in dynamic and controlled conditions, where the swimming speed and the hydrodynamics of the fabric could be compared quantitatively a superficial level (Oeffner and Lauder, 2012). It must be taken into account that design, supposedly, produced certain advantages, and based on this, they were progressively adapted (Chatard and Wilson, 2003;Berthelot et al, 2010;Neiva et al, 2011;Foster et al, 2012) revealing a better effect on the crawl and backstroke, as they offered less drag to the breaststroke and butterfly (Issurin et al, 2014).…”

“…However, it is claimed that the textile has no effect on this (Chatard and Wilson, 2003;Roberts et al, 2003), unlike other studies (Förch et al, 2009;Mountjoy et al, 2009;Hagedorn, 2013). Materials such as "poliamide6" and "poliamide6-elastane, " have had a major effect on the results (Abasi et al, 2013) and the style (Issurin et al, 2014). The approximation of the fabric to so-called "shark skin and its scales, " has revealed an improvement in the circulation and a reduction in the turbulent fluid (Wada et al, 2010), together with the swimmer's drag (Oeffner and Lauder, 2012).…”