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- All Subjects: Aerodynamics
- Creators: Mechanical and Aerospace Engineering Program
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For the testing of the golf club head, two probes were developed to measure the turbulent intensity in the flow. The probes, based on Rossow’s (1993) three probe system, compared the dynamic pressure of the flow with the stream-wise dynamic pressure in the flow. The resultant measurements could then produce the ratio of the cross-stream fluctuations in velocity to the time-averaged velocity. The turbulence intensity calculations would provide insight on the turbulence in the boundary layer flow and wake.
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.
The objectives of this project are to design a statically determinant load cell mechanism for a prototype tow tank ultimately culminating in the testing of the aerodynamic performance of a Formula One racing car model. This paper also serves as a proof of concept for force data collection for a full-sized tow tank being developed by Isabella All [8]. The project includes the design and construction of the load cell mechanism which utilizes a load cell to measure the force in a specific member of the mechanism which is then used to determine the semi-lift and drag forces for a given test model. For this specific project, a model of the front-end of an F1 racing car was used for data collection and analysis. It was found that for a short period of time within each test run, constant force data was able to be collected from the load cell which could then be transformed into semi-lift and drag force data. Ultimately, the drag coefficient acting on the model was found to be in the range of 0.9 to 1.3 which somewhat falls in line with the estimated values of 0.7 to 1.0 [1] for F1 racing vehicles. Although the final data collected may not be entirely accurate due to errors discussed in the paper, the ideas presented in this project can be fully realized with some minor changes and adjustments.
0° spoilers reduced the wake area behind the car, decreasing pressure drag but also decreasing underbody flow, causing a reduction in drag and downforce. Angled spoilers increased the wake area behind the car, increasing pressure drag but also increasing underbody flow, causing an increase in drag and downforce. Longer spoilers increased these effects compared to shorter spoilers, and short spoilers at different angles did not create significantly different effects. 0° spoilers would be best suited for cases that prioritize fuel economy or straight-line acceleration and speed due to the drag reduction, while angled spoilers would be best suited for cars requiring downforce. The angle and length of spoiler would depend on the downforce needed, which is dependent on the track.