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Description
This experiment used hotwire anemometry to examine the von Kármán vortex street and how different surface conditions affect the wake profile of circular airfoils, or bluff bodies. Specifically, this experiment investigated how the various surface conditions affected the shedding frequency and Strouhal Number of the vortex street as Reynolds Number

This experiment used hotwire anemometry to examine the von Kármán vortex street and how different surface conditions affect the wake profile of circular airfoils, or bluff bodies. Specifically, this experiment investigated how the various surface conditions affected the shedding frequency and Strouhal Number of the vortex street as Reynolds Number is increased. The cylinders tested varied diameter, surface finish, and wire wrapping. Larger diameters corresponded with lower shedding frequencies, rougher surfaces decreased Strouhal Number, and the addition of thick wires to the surface of the cylinder completely disrupted the vortex shedding to the point where there was almost no dominant shedding frequency. For the smallest diameter cylinder tested, secondary dominant frequencies were observed, suggesting harmonics.
ContributorsCoote, Peter John (Author) / Takahashi, Timothy (Thesis director) / White, Daniel (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
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Description
Active flow control for airfoil designs has been researched for the past few decades. This has been achieved through steady blowing, pulsed blowing, synthetic jets, and plasma jets. These techniques have been applied to both single and dual jet configurations. This technology was examined for a wind turbine blade application

Active flow control for airfoil designs has been researched for the past few decades. This has been achieved through steady blowing, pulsed blowing, synthetic jets, and plasma jets. These techniques have been applied to both single and dual jet configurations. This technology was examined for a wind turbine blade application so that lift and drag can be altered without needing a mechanical flap. Research was completed to also allow for thicker airfoils with more blunt trailing edges that result in the higher structural strength needed for large, heavy wind turbine blades without the negative aerodynamic effects such as boundary layer separation. This research tested steady blowing in a dual jet configuration for the S830 airfoil from the National Renewable Energy Laboratory (NREL) database of airfoils. Computational Fluid Dynamics was used in the software Ansys Fluent. Calculations were completed for a modified S830 airfoil with a rounded trailing edge surface at momentum coefficients of 0.01 for the lower jet and 0.1, 0.12, and 0.14 for the upper jet. These results were then compared to the original S830 results for the lift over drag efficiency. The design with momentum coefficients of 0.12 for the upper surface resulted in the highest increase in efficiency of 53% at an angle of attack of 12 degrees. At this momentum coefficient, the angle of attack where zero lift occurred was at -8.62 degrees, compared to the case with no blowing at -1.90 degrees. From previous research and research completed in this thesis it was concluded that active flow control is an effective technique to improve wind turbine energy collection.
ContributorsStapleton, Paige (Author) / Mertz, Benjamin (Thesis director) / Herrmann, Marcus (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
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Description
The emerging market for unmanned aerial vehicles, or UAV's, demands the development of effective design tools for small-scale aircraft. This research seeks to validate a previously developed drag build-up method for small air vehicles. Using the method, a drag prediction was made for an off-the-shelf, remotely controlled aircraft. The Oswald

The emerging market for unmanned aerial vehicles, or UAV's, demands the development of effective design tools for small-scale aircraft. This research seeks to validate a previously developed drag build-up method for small air vehicles. Using the method, a drag prediction was made for an off-the-shelf, remotely controlled aircraft. The Oswald efficiency was predicted to be 0.852. Flight tests were then conducted using the RC plane, and the aircraft performance data was compared with the predicted performance data. Although there were variations in the data due to flight conditions and equipment, the drag build up method was capable of predicting the aircraft's drag. The experimental Oswald efficiency was found to be 0.863 with an error of 1.27%. As for the CDp the prediction of 0.0477 was comparable to the experimental value of 0.0424. Moving forward this method can be used to create conceptual designs of UAV's to explore the most efficient designs, without the need to build a model.
ContributorsGavin, Tyler Joseph (Author) / Wells, Valana (Thesis director) / Garrett, Fred (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2014-05
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Description
Each year, the CanSat Competition organizers release aerospace based engineering mission objectives for collegiate teams to compete in. This year, the design is an aerodynamically stable probe that will descend from an altitude of 725 meters at a rate between 10-30 meters/sec until it reaches an altitude of 300 meters,

Each year, the CanSat Competition organizers release aerospace based engineering mission objectives for collegiate teams to compete in. This year, the design is an aerodynamically stable probe that will descend from an altitude of 725 meters at a rate between 10-30 meters/sec until it reaches an altitude of 300 meters, where it will then release a parachute as its aerobraking mechanism as it descends at 5 meters/sec until it reaches the ground. The focus of this paper is to investigate the design of the probe itself and how slender body theory and cross flow drag affect the lift and aerodynamic stability of this bluff body. A tool is developed inside of MATLAB which calculates the slender body lift as well as the lift from the cross flow drag. It then uses that information to calculate the total moment about the center of gravity for a range of angles of attack and free stream velocities. This tool is then used to optimize the geometry of the probe. These geometries are used to construct a prototype and that prototype is tested by a drop test from a 6-story building. The initial tests confirm the calculations that the probe, bluff body, is stable and self-correcting in its descent. Future work involves more high-altitude and ground-level tests that will further verify and improve on the current design.
ContributorsMcCourt, Anthony Michael (Author) / Takahashi, Timothy (Thesis director) / Herrmann, Marcus (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
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Description
This study consisted of two fundamental experiments that examined the effects of surface parameters on baseball aerodynamics. The first experiment measured drag and lift coefficients in response to varied surface treatments of a non-spinning baseball. This experiment found that rougher surfaces (rubbing mud, increased ball usage, and scuffing) decrease drag

This study consisted of two fundamental experiments that examined the effects of surface parameters on baseball aerodynamics. The first experiment measured drag and lift coefficients in response to varied surface treatments of a non-spinning baseball. This experiment found that rougher surfaces (rubbing mud, increased ball usage, and scuffing) decrease drag coefficient by up to 0.05 for Reynolds numbers of up to 1.5x105 (wind speeds of 30 m/s or 67 mph). The maximum observed increase in lift coefficient was 0.20, caused by heavily scuffing the top of the ball. These results can be explained by boundary layer transition phenomena and asymmetry in the surface roughness of the ball. A decrease in drag coefficient of 0.05 can translate to an increase in the flight distance of a batted ball by as much as 50 ft (14%), and an increase of 0.20 in lift coefficient can increase flight distance by 70 ft (19%) \u2014 numbers that can easily mean the difference between a routine fly out and a monster home run. The second experiment measured drag and lift coefficients in response to varied stitch geometries of a non-spinning, 3D-printed baseball. Increasing stitch height, width, and spacing was found to increase drag coefficient, while increasing stitch length had little effect on lift coefficient. Increasing any parameter of the stitch geometry was found to increase lift coefficient. These results can be explained by boundary layer transition phenomena, blockage effects, and asymmetry in the stitch geometry of the ball. Future work would do well to repeat these experiments with a larger wind tunnel and a more sensitive force balance. These results should also be validated at higher wind speeds, and for spinning, rather than stationary baseballs. In addition, future work should explore the degree to which surface roughness and stitch geometry affect drag and lift coefficients at different ball orientations.
ContributorsDwight, Jeremiah Robert (Author) / Squires, Kyle (Thesis director) / Steele, Bruce (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
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Description
The aerodynamics of golf club heads effect the forces on the club head throughout the swing. The bluff body geometry and passive flow control elements make the aerodynamics of golf club heads far more complex. The theory behind the geometry of the bluff body aerodynamics relies on the

The aerodynamics of golf club heads effect the forces on the club head throughout the swing. The bluff body geometry and passive flow control elements make the aerodynamics of golf club heads far more complex. The theory behind the geometry of the bluff body aerodynamics relies on the state of the boundary layer and its interaction with the golf club head. Laminar and turbulent boundary layer flow result in drag, but in varying degrees. Separation, or attachment, of the boundary layer in these laminar and turbulent boundary layer flows is part of the cause of the induced drag. Skin friction and pressure drag are the two forms of surface forces which vary according to the state of the boundary layer. To review the state of the boundary layer flow and provide validation data for the corresponding, the golf club head was tested in a wind tunnel. Drag readings from the experiment showed the lowest drag occurred while the club face was perpendicular to the flow from the range of 50 miles per hour to 90 miles per hour. Additionally, the decrease in drag varied greatly depending on the orientation of golf club head. The decrease in the coefficient for the club perpendicular to the flow was approximately 3.99*〖10〗^(-6) C_d/Re while the decrease for the club at 110° was 1.07*〖10〗^(-6) C_d/Re. The general trend of the slopes indicated the pressure drag resulted in major variations while the drag due to skin friction remained relatively constant.
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.
ContributorsBrausch, Matthew James (Author) / Takahashi, Timothy (Thesis director) / Ghods, Sina (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
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Description

The purpose of this project is to assess how well today’s youth is able to learn new skills<br/>in the realm of engineering through online video-conferencing resources. Each semester of this<br/>last year, a class of students in both 3rd and 6th grade learned about computer-aided design (CAD)<br/>and 3D printing through their

The purpose of this project is to assess how well today’s youth is able to learn new skills<br/>in the realm of engineering through online video-conferencing resources. Each semester of this<br/>last year, a class of students in both 3rd and 6th grade learned about computer-aided design (CAD)<br/>and 3D printing through their laptops at school. This was done by conducting online lessons of<br/>TinkerCAD via Zoom and Google Meet. TinkerCAD is a simple website that incorporates easy-to-learn skills and gives students an introduction to some of the basic operations that are used in<br/>everyday CAD endeavors. In each lesson, the students would learn new skills by creating<br/>increasingly difficult objects that would test both their ability to learn new skills and their overall<br/>enjoyment with the subject matter. The findings of this project reflect that students are able to<br/>quickly learn and retain new information relating to CAD. The group of 6th graders was able to<br/>learn much faster, which was expected, but the class of 3rd graders still maintained the<br/>knowledge gained from previous lessons and were able to construct increasingly complicated<br/>objects without much struggle. Overall, the students in both classes enjoyed the lessons and did<br/>not find them too difficult, despite the online environment that we were required to use. Some<br/>students found the material more interesting than others, but in general, the students found it<br/>enjoyable to learn about a new skill that has significant real-world applications

ContributorsWerner, Matthew (Author) / Song, Kenan (Thesis director) / Lin, Elva (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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

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
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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

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
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Description
An understanding of aerodynamics is crucial for automobile performance and efficiency. There are many types of “add-on” aerodynamic devices for cars including wings, splitters, and vortex generators. While these have been studied extensively, rear spoilers have not, and their effects are not as widely known. A Computational Fluid Dynamics (CFD)

An understanding of aerodynamics is crucial for automobile performance and efficiency. There are many types of “add-on” aerodynamic devices for cars including wings, splitters, and vortex generators. While these have been studied extensively, rear spoilers have not, and their effects are not as widely known. A Computational Fluid Dynamics (CFD) and wind tunnel study was performed to study the effects of spoilers on vehicle aerodynamics and performance. Vehicle aerodynamics is geometry dependent, meaning what applies to one car may or may not apply on another. So, the Scion FRS was chosen as the test vehicle because it is has the “classic” sports car configuration with a long hood, short rear, and 2+2 passenger cabin while also being widely sold with a plethora of aftermarket aerodynamic modifications available. Due to computing and licensing restrictions, only a 2D CFD simulation was performed in ANSYS Fluent 19.1. A surface model of the centerline of the car was created in SolidWorks and imported into ANSYS, where the domain was created. A mesh convergence study was run to determine the optimum mesh size, and Realizable k-epsilon was the chosen physics model. The wind tunnel lacked equipment to record quantifiable data, so the wind tunnel was utilized for flow visualization on a 1/24 scale car model to compare with the CFD.

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.
ContributorsNie, Alexander (Author) / Wells, Valana (Thesis director) / Huang, Huei-Ping (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2019-12