Matching Items (9)
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 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
Description
The FoF1 ATP synthase is a molecular motor critical to the metabolism of virtually all life forms, and it acts in the manner of a hydroelectric generator. The F1 complex contains an (αβ)3 (hexamer) ring in which catalysis occurs, as well as a rotor comprised by subunit-ε in addition to the coiled-coil and globular foot domains of subunit-γ. The F1 complex can hydrolyze ATP in vitro in a manner that drives counterclockwise (CCW) rotation, in 120° power strokes, as viewed from the positive side of the membrane. The power strokes that occur in ≈ 300 μsec are separated by catalytic dwells that occur on a msec time scale. A single-molecule rotation assay that uses the intensity of polarized light, scattered from a 75 × 35 nm gold nanorod, determined the average rotational velocity of the power stroke (ω, in degrees/ms) as a function of the rotational position of the rotor (θ, in degrees, measured in reference to the catalytic dwell). The velocity is not constant but rather accelerates and decelerates in two Phases. Phase-1 (0° - 60°) is believed to derive power from elastic energy in the protein. At concentrations of ATP that limit the rate of ATP hydrolysis, the rotor can stop for an ATP-binding dwell during Phase-1. Although the most probable position that the ATP-binding dwell occurs is 40° after the catalytic dwell, the ATP-binding dwell can occur at any rotational position during Phase-1 of the power stroke. Phase-2 of the power stroke (60° - 120°) is believed to be powered by the ATP-binding induced closure of the lever domain of a β-subunit (as it acts as a cam shaft against the γ-subunit). Algorithms were written, to sort and analyze F1-ATPase power strokes, to determine the average rotational velocity profile of power strokes as a function of the rotational position at which the ATP-binding dwell occurs (θATP-bd), and when the ATP-binding dwell is absent. Sorting individual ω(θ) curves, as a function of θATP-bd, revealed that a dependence of ω on
θATP-bd exists. The ATP-binding dwell can occur even at saturating ATP concentrations. We report that ω follows a distinct pattern in the vicinity of the ATP-binding dwell, and that the ω(θ) curve contains the same oscillations within it regardless of θATP-bd. We observed that an acceleration/deceleration dependence before and after the ATP-binding dwell, respectively, remained for increasing time intervals as the dwell occurred later in Phase-1, to a maximum of ≈ 40°. The results were interpreted in terms of a model in which the ATP-binding dwell results from internal drag at a variable position on the γε rotor.
θATP-bd exists. The ATP-binding dwell can occur even at saturating ATP concentrations. We report that ω follows a distinct pattern in the vicinity of the ATP-binding dwell, and that the ω(θ) curve contains the same oscillations within it regardless of θATP-bd. We observed that an acceleration/deceleration dependence before and after the ATP-binding dwell, respectively, remained for increasing time intervals as the dwell occurred later in Phase-1, to a maximum of ≈ 40°. The results were interpreted in terms of a model in which the ATP-binding dwell results from internal drag at a variable position on the γε rotor.
ContributorsBukhari, Zain Aziz (Author) / Frasch, Wayne D. (Thesis director) / Allen, James P. (Committee member) / Redding, Kevin (Committee member) / School of Molecular Sciences (Contributor) / Department of Physics (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
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 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
Description
This thesis focused on verifying previous literature and research that has been conducted on different spherical objects. Mainly, verifying literature that examines both how surface roughness contributes to the overall drag and how wake turbulence is affected by different surface roughness. The goal of this project is to be able to capture data that shows that the flow transition from laminar to turbulent occurs at lower Reynolds numbers for a rough spherical object rather than a perfectly smooth sphere. In order to achieve this goal, both force balance testing and hot-wire testing were conducted in the Aero-lab complex in USE170. The force balance was mounted and used in the larger wind tunnel while the hot-wire probe was mounted and used in the smaller wind tunnel. Both of the wind tunnels utilized LABVIEW software in order to collect and convert the qualitative values provided by the testing probes and equipment. The two main types of testing equipment that were used in this project were the force balance and the hot-wire probe. The overall results from the experiment were inconclusive based on the limitations of both the testing probes and the testing facility itself. Overall, the experiment yielded very limited results due to these limitations.
ContributorsMilroy, Maxwell (Author) / Takahashi, Timothy (Thesis director) / Adrian, Ronald (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / W. P. Carey School of Business (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
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 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
Description
Control algorithm development for quadrotor is usually based solely on rigid body dynamics neglecting aerodynamics. Recent work has demonstrated that such a model is suited only when operating at or near hover conditions and low-speed flight. When operating in confined spaces or during aggressive maneuvers destabilizing forces and moments are induced due to aerodynamic effects. Studies indicate that blade flapping, induced drag, and propeller drag influence forward flight performance while other effects like vortex ring state, ground effect affect vertical flight performance. In this thesis, an offboard data-driven approach is used to derive models for parasitic (bare-airframe) drag and propeller drag. Moreover, thrust and torque coefficients are identified from static bench tests. Among the two, parasitic drag is compensated for in the position controller module in the PX4 firmware. 2-D circular, straight line, and minimum snap rectangular trajectories with corridor constraints are tested exploiting differential flatness property wherein altitude and yaw angle are constant. Flight tests are conducted at ASU Drone Studio and results of tracking performance with default controller and with drag compensated position controller are presented. Root mean squared tracking error in individual axes is used as a metric to evaluate the model performance. Results indicate that, for circular trajectory, the root mean squared error in the x-axis has reduced by 44.54% and in the y-axis by 39.47%. Compensation in turn degrades the tracking in both axis by a maximum under 12% when compared to the default controller for rectangular trajectory case. The x-axis tracking error for the straight-line case has improved by 44.96% with almost no observable change in the y-axis.
ContributorsNolastname, Kashyap Sathyamurthy (Author) / Zhang, Wenlong (Thesis advisor) / Yong, Sze Zheng (Committee member) / Berman, Spring (Committee member) / Arizona State University (Publisher)
Created2020
Description
The Transonic Area Rule, developed by Richard T. Whitcomb in the early 1950s, revolutionized high-speed flight because its insight allowed engineers to reduce and/or delay the transonic drag rise. To this day, it is the rationale behind “coke-bottle” sculpturing (indenting the aircraft fuselage at the wing-fuselage junction) to alter the cross-sectional area development of the body. According to Whitcomb, this indentation is meant to create a smoother transition of cross-sectional area development of the body and consequently would reduce the number of shocks on the body, their intensity, and their shock pattern complexity. Along with this, modeling of a geometry’s transonic drag rise could be simplified by creating a comparable body of revolution with the same cross-sectional area development as the original geometry. Thus, the Transonic Area Rule has been advertised as an aerodynamic multitool. This new work probes the underlying mechanics of the Transonic Area Rule and determines just how accurate it is in producing its advertised results. To accomplish this, several different wave-drag approximation methods were used to replicate and compare the results presented in Whitcomb’s famous 1952 report16. These methods include EDET (Empirical Drag Estimation Technique)4, D2500 (Harris Wave Drag program)6, and CFD (Computational Fluid Dynamics) analysis through SU25. Overall drag increment data was collected for comparison with Whitcomb’s data. More in-depth analysis was then done on the flow conditions around the geometries using CFD solution plots.
After analysis of the collected data was performed, it was discovered that this data argued against Whitcomb’s comparable body of revolution claim as no cases were demonstrated where the comparable body and original body yielded similar drag rise characteristics. Along with this, shock structures and patterns were not simplified in two of the three cases observed and were instead complicated even further. The only exception to this observation was the swept wing, cylindrical body in which all shocks were virtually eliminated at all observed Mach numbers. For the reduced transonic drag rise claim, the data argued in favor of this as the drag rise was indeed reduced for the three observed geometries, but only for a limited Mach number range.
ContributorsArmenta, Francisco Xavier (Author) / Takahashi, Timothy T (Thesis advisor) / Kim, Jeonglae (Committee member) / Rodi, Patrick (Committee member) / Arizona State University (Publisher)
Created2021
Description
This experiment investigated the effects of different vortex generator sizes and configurations on the induced drag of a 2006 Honda Accord, with comparisons to a control test. Tuft tests were carried out prior to any data collection. The tufts were placed along the roof and rear window of the vehicle for each of the five vortex generator types. Video was taken of the tufts for each set of vortex generators, allowing a visual comparison of the flow characteristics with comparison to the control. Out of the four vortex generators tested, the two that yielded the most substantial change in the flow characteristics were utilized. The data collection was conducted utilizing the two sets of vortex generators, one large and one small, placed in three different locations along the roof of the vehicle. Over a course of four trials of data collection, each vortex generator size and configuration was tested two times along a stretch of Interstate 60, with each data set consisting of five minutes heading east, followed by five minutes heading west. Several experimental parameters were collected using an OBD II Bluetooth Adaptor, which were logged using the software compatible with the adaptor. This data was parsed and analyzed in Microsoft Excel and MATLAB. Utilizing an Analysis of Variance (ANOVA) analytical scheme, the data was generalized to account for terrain changes, steady state speed fluctuations, and weather changes per night. Overall, upon analysis of the data, the vortex generators showed little-to-no benefit to either the fuel efficiency or engine load experienced by the vehicle during the duration of the experiment. This result, while unexpected, is substantial as it shows that the expenditure of purchasing these vortex generators for this make and model of vehicle, and potentially other similar vehicles, is unnecessary as it produces no meaningful benefit.
ContributorsMazza, Seth (Author) / Walther, Chase (Co-author) / Takahashi, Timothy (Thesis director) / Middleton, James (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2022-05
Description
This experiment investigated the effects of different vortex generator sizes and configurations on the induced drag of a 2006 Honda Accord, with comparisons to a control test. Tuft tests were carried out prior to any data collection. The tufts were placed along the roof and rear window of the vehicle for each of the five vortex generator types. Video was taken of the tufts for each set of vortex generators, allowing a visual comparison of the flow characteristics with comparison to the control. Out of the four vortex generators tested, the two that yielded the most substantial change in the flow characteristics were utilized. The data collection was conducted utilizing the two sets of vortex generators, one large and one small, placed in three different locations along the roof of the vehicle. Over a course of four trials of data collection, each vortex generator size and configuration was tested two times along a stretch of Interstate 60, with each data set consisting of five minutes heading east, followed by five minutes heading west. Several experimental parameters were collected using an OBD II Bluetooth Adaptor, which were logged using the software compatible with the adaptor. This data was parsed and analyzed in Microsoft Excel and MATLAB. Utilizing an Analysis of Variance (ANOVA) analytical scheme, the data was generalized to account for terrain changes, steady state speed fluctuations, and weather changes per night. Overall, upon analysis of the data, the vortex generators showed little-to-no benefit to either the fuel efficiency or engine load experienced by the vehicle during the duration of the experiment. This result, while unexpected, is substantial as it shows that the expenditure of purchasing these vortex generators for this make and model of vehicle, and potentially other similar vehicles, is unnecessary as it produces no meaningful benefit.
ContributorsWalther, Chase (Author) / Mazza, Seth (Co-author) / Takahashi, Timothy (Thesis director) / Middleton, James (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2022-05