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All Subjects: Aerodynamics
Creators: Bergmann, Ande

The Analytical Drag Analysis of Drafting NASCAR Models

Description

The following analysis was conducted at the Arizona State University open loop wind tunnel. Two 1/24-th scale NASCAR models were placed in a wind tunnel test section and were adjusted to study drafting that commonly occurs at superspeedway racetracks. The purpose of the experiment was to determine how drafting affects a leading and trailing car through changes in distance. A wind tunnel model was developed consisting of two 2019 NASCAR Chevy Camaro race car models, two bar-style load cells, and a programmed Arduino UNO. Two trials were run at each drafting distance, 0, 0.5, 1, 1.5, and 2 car lengths apart. Each trial was run at a wind tunnel velocity of 78 mph (35 m/s) and force data was collected to represent the drag effects at each drafting location. Based on previously published experimentation, this analysis provided important data that related drafting effects in scale model race cars to full-scale vehicles. The experiment showed that scale model testing can be accurately completed when the wind tunnel Reynolds number is of the same magnitude as a full-scale NASCAR. However, the wind tunnel data collected was proven to be fully laminar flow and did not compare to the flow characteristics of typically turbulent flow seen in superspeedway races. Overall, the analytical drag analysis of drafting NASCAR models proved that wind tunnel testing is only accurate when many parameters are met and should only be used as a method of validation to full-scale testing.

ContributorsOlszak, Parker T (Author) / Takahashi, Timothy (Thesis director) / Kasbaoui, Mohamed (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)

Created2021-05

An Experimental Investigation of Aerodynamic Drag on Different Cycling Outfits

Description

An experimental investigation was conducted to calculate the aerodynamic drag on a cyclist wearing different types of clothing. The different outfits worn for this experiment were a professional skinsuit, a professional cycling kit, a t-shirt and shorts, and a long-sleeved flannel and jeans. The aerodynamic drag was ultimately found using the coast down method, a process in which a cyclist increases their speed to a chosen maximum threshold, and upon reaching this speed, ceases the pedal stroke and maintains the aero position until the bicycle comes to a stop. The data was gathered using an AeroPod, speed sensor, and GPS unit. The data gathered was imported into Excel for data analysis. The average CdA values at race speed (26-30 ft/s) for the skinsuit, cycling kit, t-shirt and shorts, and flannel were calculated to be 4.180 ft2, 3.668 ft2, 4.884 ft2, and 4.223 ft2, respectively. These race speed averages were found using data from three separate Ironman Triathlons. The cycling kit was found to be the most aerodynamic at the race speed. The results of this study reveal that cycling apparel can only be optimized for a small range of speeds and cycling outside of this optimal range delays the initiation of the reduction of boundary layer separation, thus resulting in more critical time spent in the flow transition region. The skinsuit’s performance was more aerodynamically efficient than the cycling kit at speeds greater than 36.8 mph. The cycling kit is more aerodynamic for speeds slower than 36.8 mph. The slickness of the skinsuit was found to be detrimental to the cyclist’s aerodynamic drag, as the lack of roughness on the skinsuit prevented the initiation of turbulent flow, which results in a decrease in drag. Overall, the experiment confirmed the hypothesis that a cyclist is more aerodynamic when wearing cycling apparel as opposed to casual, loose-fitting clothing.

ContributorsGlynn, Julia Daniel (Co-author) / Duffy, Kyle (Co-author) / Takahashi, Timothy (Thesis director) / Bergmann, Ande (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Department of Information Systems (Contributor) / Barrett, The Honors College (Contributor)

Created2019-12