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Full-Text Articles in Aerodynamics and Fluid Mechanics
Aerodynamic Dimpling For The Nose Cone Of A High-Power Competition Rocket, Graham Geoffrey Monroe
Aerodynamic Dimpling For The Nose Cone Of A High-Power Competition Rocket, Graham Geoffrey Monroe
Mechanical Engineering ETDs
This thesis investigates nose cone dimpling for the reduction of the aerodynamic drag of a Level 3 High-Power amateur rocket. Two rocket launches were conducted. The first used a COTS nose cone with a smooth surface. A dimple distribution was created according to dimensions calculated by Sandia National Laboratories’ proprietary Right- Size Dimple Evaluator. A dimpled nose cone, designed with geometry matching the COTS component, was 3D printed. Axial acceleration and barometric pressure data, recorded by an onboard flight computer, were used to calculate and plot the drag coefficient as a function of the Reynolds number for the smooth and …
Husker Motorsports Active Drag Reduction System, Creighton Hughes, Evan Killian, Micah Busboom, Aj Johnson, Jude Steffen
Husker Motorsports Active Drag Reduction System, Creighton Hughes, Evan Killian, Micah Busboom, Aj Johnson, Jude Steffen
Honors Theses
Formula SAE is a multifaceted competition that involves student teams designing and competing with an open-wheel style race car. There are 5 different dynamic events included in the competition. Each event requires a unique aerodynamic setup to have the best performance possible. This design project focuses on a drag reduction system (DRS) that will improve aerodynamic performance, resulting in faster lap times and increased competitiveness. Key features include a direct electronic actuation mechanism that will allow the rear wing to be adjusted during a race. The benefits of the DRS system, include increased speed, improved handling, and greater fuel efficiency …
Potential Of Hydrodynamic Metamaterial Cloak For Drag Reduction, Rong Zou
Potential Of Hydrodynamic Metamaterial Cloak For Drag Reduction, Rong Zou
McKelvey School of Engineering Theses & Dissertations
Metamaterials are rationally designed artificial materials composed of tailored functional building blocks densely packed into an effective material. While metamaterials historically are primarily thought to be associated with negative index of refraction and invisibility cloaking in electromagnetism or optics, it turns out that the simple metamaterial concept also applies to many other areas of physics namely the thermodynamics, classical mechanics including elastostatics, acoustics, fluid dynamics and elastodynamics, and in principle also to the quantum mechanics. The goal of this thesis is to introduce and evaluate the potential of a hydrodynamic metamaterial cloak for drag reduction of objects in viscous flow. …
On The Reduction Of The Driving Force In Shear-Driven Flows, Sakib Shadman
On The Reduction Of The Driving Force In Shear-Driven Flows, Sakib Shadman
Electronic Thesis and Dissertation Repository
In shear-driven flows, an external driving force is needed to maintain the relative movement of horizontal plates. This thesis presents a systematic analysis on using spatially periodic heating and grooved surfaces to control this force. It is found that the use of periodic heating creates a buoyancy-driven effect that always reduces this force. The use of proper heating may even lead to the complete elimination of this force. It is further found that the use of isothermal grooved surfaces always enhances flow resistance, resulting in an increase of this force. When grooves and heating are applied together, their interaction induces …
Base Pressure Control Using Micro-Jets In Supersonic Flow Regimes, Vigneshvaran Sethuraman, Sher Afghan Khan
Base Pressure Control Using Micro-Jets In Supersonic Flow Regimes, Vigneshvaran Sethuraman, Sher Afghan Khan
International Journal of Aviation, Aeronautics, and Aerospace
Base pressure plays a vital role in aerospace-related applications and its control is essential in reduction of drag and improving fuel consumption. Low pressure at the base of Rockets, Missiles, bombs and shells are a very common problem happening at transonic and supersonic speeds. In most of the cases there is a significant dip in pressure at the base region which will have implications on the design of aerospace vehicles. This paper presents an experimental investigation carried out for flow control at supersonic regimes. Experiments were conducted to measure the base pressure in the base region and wall pressure distribution …
Computational Fluid Dynamic Analysis Of Microbubble Drag Reduction Systems At High Reynolds Number, John D. Goolcharan
Computational Fluid Dynamic Analysis Of Microbubble Drag Reduction Systems At High Reynolds Number, John D. Goolcharan
FIU Electronic Theses and Dissertations
Microbubble drag reduction (MBDR) is an effective method to improve the efficiency of fluid systems. MBDR is a field that has been extensively studied in the past, and experimental values of up to 80% to 90% drag reduction have been obtained. The effectiveness and simplicity of MBDR makes it a viable method for real world applications, particularly in naval applications where it can reduce the drag between the surface of ships and the surrounding water. A two dimensional single phase model was created in ANSYS Fluent to effectively model the behavior of bubble laden flow over a flat plate. This …
A Qualitative Experimental Study Of Drag Reduction Devices For Tractor Trailers With Ground Effects, Nicolas Robert Reed
A Qualitative Experimental Study Of Drag Reduction Devices For Tractor Trailers With Ground Effects, Nicolas Robert Reed
Masters Theses
This is an experimental qualitative study of how drag reduction devices affect air flow around a tractor trailer. A 1/32 scale detail model of a truck with its trailer was used for testing in a 20"x14" low speed wind tunnel at the University of Tennessee Space Institute. Major modifications were made to the wind tunnel so that it would include a moving bed (floor) section for ground effect simulation. This was done to accurately simulate relative ground movement with the truck being held stationary in the tunnel flow.
Drag reduction devices were designed based on aerodynamic fundamental understanding for streamlining …
Drag Reduction Of A Modern Straight Truck, Drew Landman, Matthew Cragun, Mike Mccormick, Richard Wood
Drag Reduction Of A Modern Straight Truck, Drew Landman, Matthew Cragun, Mike Mccormick, Richard Wood
Mechanical & Aerospace Engineering Faculty Publications
A wind tunnel test program was conducted at the Langley Full Scale Tunnel (LFST) to evaluate the performance of five passive drag reduction configurations on a modern straight truck at full scale. Configurations were tested in a build-up fashion with results representing a cumulative effect. Tested configurations include a front valance, a front box fairing, a boat-tail, an ideal side-skirt, and a practical side-skirt. Configurations were evaluated over a nominal 9 degree yaw sweep to establish wind averaged drag coefficients using SAE J1252. Genuine replicate yaw sweeps were used in an uncertainty analysis. Results show up to 28% improvement in …
Analysis Of A Passive Flow Control Device Via Flow Visualization Techniques, Cheryl R. Graham, Shi (Peter) Huang
Analysis Of A Passive Flow Control Device Via Flow Visualization Techniques, Cheryl R. Graham, Shi (Peter) Huang
Aerospace Engineering
This report details an experiment done to verify the effectiveness of a passive flow control system on a two-dimensional bluff body, blunt trailing edge model in controlling wake dimension and Karman vortex sheds. An earlier experiment by Park, et.al.[1] performed analysis via wind tunnel pressure testing and computerized model to determine the ideal proportions of such a tab design and identify the flow properties responsible for the potential drag reduction. To obtain visual verification of the existence of these concepts, a bluff body model proportionally identical to the one used by Park, et.al., was designed and tested in a water …
Understanding Practical Limits To Heavy Truck Drag Reduction, Drew Landman, Richard Wood, Whitney Seay, John Bledsoe
Understanding Practical Limits To Heavy Truck Drag Reduction, Drew Landman, Richard Wood, Whitney Seay, John Bledsoe
Mechanical & Aerospace Engineering Faculty Publications
A heavy truck wind tunnel test program is currently underway at the Langley Full Scale Tunnel (LFST). Seven passive drag reducing device configurations have been evaluated on a heavy truck model with the objective of understanding the practical limits to drag reduction achievable on a modern tractor trailer through add-on devices. The configurations tested include side skirts of varying length, a full gap seal, and tapered rear panels. All configurations were evaluated over a nominal 15 degree yaw sweep to establish wind averaged drag coefficients over a broad speed range using SAE J1252. The tests were conducted by first quantifying …