A study of drag reduction with textile roughness on a cyclist model

X. Y. Hsu, Jiun Jih Miau, T. H. Ku, J. J. Chen, W. C. Yuan, Y. H. Lai, Y. R. Chen, Y. J. Chen, C. H. Tseng, C. H. Chen, S. S. Jan, Y. S. Ciou, Y. Chen, C. W. Chiu

Research output: Contribution to journalArticlepeer-review

Abstract

Efforts were made to examine the effect of textile roughness for the reduction of aerodynamic drag experienced on a cyclist model. First of all, flow visualization experiments were conducted in a water channel with a 1/5 scale cyclist model to identify the flow separation lines on the contoured surface. Subsequently, based on the information learned, the idea of delaying flow separation on the model surface was implemented by means of sport suits. Seven sport suits featuring different textile materials and local roughness patterns were tested on a full-scale cyclist model in wind tunnel experiments, in addition to a reference case without a sport suit. From the CD data deduced, we identified a critical condition in most of the cases studied, featuring a least drag coefficient occurred at a Reynolds number within the flow speed range studied. For the best case found, the drag coefficient is amounted 7.5% less than that of the reference case at the same Reynolds number. Furthermore, the Cp and Cprms values reduced from the pressure measurements on the cyclist model with the sport suits unveil a trend that the reduction of drag actually infers the retreat of the local flow separation lines toward the rear side of the body accompanied with less severe the flow unsteadiness.

Original languageEnglish
Pages (from-to)1206-1230
Number of pages25
JournalJournal of the Textile Institute
Volume113
Issue number6
DOIs
Publication statusPublished - 2022

All Science Journal Classification (ASJC) codes

  • Materials Science (miscellaneous)
  • General Agricultural and Biological Sciences
  • Polymers and Plastics
  • Industrial and Manufacturing Engineering

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