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http://dx.doi.org/10.5407/jksv.2021.19.3.046

Experimental study on the drag reduction of a helmet for paragliding  

Hwang, Jongbin (Department of Mechanical Engineering, Ulsan National Institute of Science and Technology)
Park, Jungmok (Gin Gliders Inc.)
Song, Jinseok (Gin Gliders Inc.)
Kim, Jooha (Department of Mechanical Engineering, Ulsan National Institute of Science and Technology)
Publication Information
Journal of the Korean Society of Visualization / v.19, no.3, 2021 , pp. 46-53 More about this Journal
Abstract
In the present study, wind tunnel experiments were performed to reduce the drag of a paragliding helmet in the range of Reynolds numbers from 46,000 to 155,000. The drag force of the helmet model with dimples and deflectors installed was measured by varying the dimple depth and the slant angle of the deflector. The dimples were effective in reducing the drag at low Reynolds numbers, but no significant drag reduction was found in the Reynolds number range in which an actual paraglider flight takes place. On the other hand, the deflector installed tangentially to the side outline of the helmet showed an average drag reduction of 7% in the flight Reynolds number range of real paragliding. This was because the deflector shrunk the size of the wake region and moved the wake region downstream of the deflector.
Keywords
Paragliding helmet; Dimple; Deflector; Drag; Flow separation; Wake;
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