Aerodynamics and Fluid Mechanics Commons^™

Computational Analysis Of A Naca 0012 Straight Wing At Various Reynolds Numbers Approaching Stall, John E. Crowe Iii

College of Graduate Studies: Theses & Dissertations

As the capabilities and power of computational resources improve with each passing year, the implementation of simulation in the field of aerospace engineering also increases due to its increased efficiency, as it allows for reducing both time and resources. In this study, a computational method is created and tested for determining and visualizing the effect of increasing flow velocity on a NACA 0012 3D wing as it approaches and reaches stall. For this study, the flow over a NACA 0012 3D wing is simulated using a Reynolds-averaged Navier Stokes simulation at angles of attack of 6, 8, 10, 12, and …

Implementation Of Cavity Vortex Generators To Mitigate Stall And Ice Accretion On The Naca 0012, Eric Pernell

College of Graduate Studies: Theses & Dissertations

With the growing environmental concerns of international aviation carbon emissions are driven by the ever-increasing commercial aviation traffic. This study aims to increase the aerodynamic efficiency of the NACA 0012, by implementing cavity vortex generators with the intent to increase the effective stall angle without a substantial increase of drag. This study is performed with Reynolds Averaged Navier-Stokes (RANS) at a low Reynolds of 5.0E+04 with varying cavity depths along the leading edge. The depths study is placed at 10 percent cord at depths of 3, 5, and 10 percent cord. All cavity vortex generators effectively increased the stall angle …

Aeroelastic Phenomena Of Fixed-Wing Aircraft In Transonic And Supersonic Flows Using A Tightly-Coupled Computational Approach, John C. Havenar

College of Graduate Studies: Theses & Dissertations

Aeroelastic phenomena encountered during flight have considerable effects on the aerodynamic characteristics of fixed-wing aircraft. Transonic aeroelastic phenomena are often characterized by unique flow features which have complex ramifications for aircraft in transonic flight. Computational study of high-speed aeroelastic phenomena requires a fully-coupled aeroelastic algorithm. A series of wing designs are studied with a computational finite volume method solver accompanied by a finite element method solver for the calculation of structural deformation. The computational model for the flow field is validated with experimental data. Modeled flight conditions include transonic flows with bordering subsonic and supersonic cases included for completeness. The …

Fluid Flow And Thermal Performance Investigation Of Twisted Elliptical Tubes For Use In High Prandtl Number Systems, Connor F. Donlan

Theses and Dissertations

The development of clean energy systems is paramount to reducing mankind's climate impact. These clean energy systems include solar, wind, and nuclear power where nuclear power shows a reduced lifetime carbon dioxide footprint per kilowatt hour compared to other sources [102]. Advanced nuclear reactors, fusion energy systems, and concentrated solar power designers are looking at using molten salt heat transfer fluids and improved heat exchanger design to increase power production and efficiency of clean energy systems. The improving heat transfer within the main heat transfer components within advanced nuclear reactors will enable increased efficiencies and power production.

Heat transfer improvements …

Simulation Of Reacting Supersonic Flow In A Cavity Flameholder, Mohamed Benjelloun Touimi

Electronic Theses and Dissertations

Scramjet engines, or Supersonic Combustion Ramjets, are pivotal for achieving and maintaining hypersonic flight speeds. These engines leverage the high-speed airflow to compress and mix air and fuel for combustion. A significant challenge in Scramjet engine design is ensuring stable and efficient combustion within this high-speed environment. Cavity flameholders are crucial components that stabilize the combustion process by creating a subsonic region where the fuel-air mixture can ignite and sustain combustion. This research simulates this supersonic flow within the combustion chamber to accurately model and analyze the combustion dynamics. Various turbulence models, including RANS, and DES, are evaluated for their …

Aerothermodynamic Analysis Of A Linear Aerospike Fueled With Liquid Methane Using Cfd, Aidan Rowell

Honors College Theses

Renewed interest in manned spaceflight, mostly spurred by the advancement of commercial spacecraft, has led to growing interest in improving the efficiency of rocket engines. Aerospike nozzles have the potential to provide this boost in efficiency to spacecraft and thus lower costs and increase payload capacity. This type of nozzle is what is known as altitude adjusting and can significantly increase efficiency. When paired with propellants such as methane/oxygen, which can be manufactured in-situ on some planetary bodies and has a higher density than traditional propellants like liquid hydrogen/liquid oxygen, even more efficiency gain can be achieved. To understand the …

Experimentatal And Numerical Investigation Of Turbojet Engine Performance, Emissions, And Noise/Vibrations Using Jet-A And F24 Fuel, John W. Mcafee Jr

College of Graduate Studies: Theses & Dissertations

Drastic improvement in cost effectiveness of high-power computing resources has generated a great interest numerical simulation to reduce the overhead cost of engine manufacturing, maintenance, and environmental concerns of engine testing. To accomplish this goal, this research presents the differences between military F24 fuel and commercial aviation fuel Jet-A from a thermochemical and engine performance perspective. This experimental data was used to create and validate a numerical model of the engine used in the experiments fueled with both Jet-A and F24 fuels. The experimental data was collected using a research based single stage turbojet engine outfitted with many sensors for …

Comprehensive Review And Development Of A High-Pressure Hydraulic Impedance Tube For Vibroacoustic Attenuator Characterization, Matthew D. Beals

Dissertations, Master's Theses and Master's Reports

This research establishes a versatile test bench for characterizing hydraulic vibroacoustic attenuators. The primary evaluation metric is the transfer matrix, determined experimentally, with an emphasis on key properties such as transmission loss. To ensure accuracy and broad applicability, the methodology is based on industry-standard techniques for determining the transfer matrix. A comprehensive literature review consolidates existing approaches for hydraulic attenuator characterization. The test bench features a hydraulic impedance tube equipped with eight dynamic pressure transducer (DPT) taps strategically positioned before and after the sample interface. This setup accommodates arbitrary samples terminated with standard hydraulic fittings. Using ASTM E2611, the transfer …

Analysis Of Variations In Flow-Independent Liquid Jet-In-Crossflow Injections, Michael Scott

Honors Undergraduate Theses

Liquid fuel injection is a critical mechanism for the deliverance of liquid fuel in contemporary aircraft propulsion combustion systems due to its outsized influence in providing optimal combustion conditions and improving overall aircraft efficiency and performance. Despite this, these liquid jet in crossflow (LJIC) systems are highly variable due to conditions in the jet and the surrounding airflow, leading to variability in performance behavior and inconsistency in fuel mixing and combustion efficiency. This has prompted the introduction of solid pintile obstructions of novel designs to provide a more flow-independent fuel injection scheme and decrease variability of the jet properties against …

Dynamics Of A 3-D Inlet/Isolator Measured With Fast Pressure-Sensitive Paint, Andrew N. Bustard, Mark E. Noftz, Mitsugu Hasegawa, Hirotaka Sakaue, Joseph S. Jewell, Nicholas J. Bisek, Thomas J. Juliano

Publications

Fast pressure-sensitive paint (PSP) was applied to an inlet/isolator designed using the Osculating Internal Waverider Inlet with Parallel Streamlines (OIWPS) method. The dorsal isolator surface pressure was measured using anodized-aluminum PSP through transparent cast acrylic that makes up the ventral portion of the isolator. Temperature-sensitive paint was utilized to correct for the PSP’s temperature sensitivity. The model was tested under Mach 5.7 flow at Re = 8.5 ×106 /m and 10.2 ×106 /m in the AFOSR–Notre Dame Large Mach-6 Quiet Tunnel (ANDLM6QT) under conventional noise conditions. Flow phenomena, such as shocks originating in the inlet and flow separation at the …

Forced Displacement Technique For Measuring Blunt Body Aerodynamics In A Magnetic Suspension Wind Tunnel, Mark Schoenenberger, David Cox, Colin Britcher, Caleb Hull

Mechanical & Aerospace Engineering Faculty Publications

The Old Dominion University/NASA Langley 6-Inch Magnetic Suspension Wind Tunnel has developed the ability to levitate blunt bodies which can oscillate freely about the yaw axis. This allows for the measurement of static and dynamic stability coefficients without sting interference. The magnetic suspension controller introduces other translational forces which affect the vehicle dynamics complicating data reduction. Exciting model oscillations in a reliable way has also been a challenge. A new test method has been developed that produces capsule oscillations from forced oscillatory translational motion at the resonant yaw oscillatory frequency of the capsule. After oscillations are excited, the translational forcing …

Depressurization Characteristics Of Steam-Based Reciprocating Vacuum Pump, Hongling Deng

Dissertations

This dissertation introduces a novel vacuum technology that leverages low-pressure saturated steam and cooling-controlled condensation, offering an efficient way to utilize low-grade thermal energy sources like waste heat, steam, or solar energy. At the heart of this technology is a unique duo-chamber vacuum pump system, featuring a reciprocating piston and a heat-conductive wall, designed to generate a vacuum through steam-condensation and cooling processes.

The core of this research lies in developing and validating mechanistic models for the steam-condensation depressurization process, a complex phenomenon involving phase change and transport mechanisms. Prior to this work, these mechanisms were not sufficiently modeled or …

Numerical Study Of Owls' Leading-Edge Serrations, Asif Shahriar Nafi, Nikolaos Beratlis, Elias Balaras, Roi Gurka

Physics and Engineering Science

Owls' silent flight is commonly attributed to their special wing morphology combined with wingbeat kinematics. One of these special morphological features is known as the leading-edge serrations: rigid miniature hook-like patterns found at the primaries of the wings' leading-edge. It has been hypothesized that leading-edge serrations function as a passive flow control mechanism, impacting the aerodynamic performance. To elucidate the flow physics associated with owls' leading-edge serrations, we investigate the flow-field characteristic around a barn owl wing with serrated leading-edge geometry positioned at 20° angle of attack for a Reynolds number of 40 000. We use direct numerical simulations, where …

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 …

Investigation And Control Of Görtler Vortices In High-Speed Flows, Omar Es-Sahli

Theses and Dissertations

High-amplitude freestream turbulence and surface roughness elements can excite a laminar boundary-layer flow sufficiently enough to cause streamwise-oriented vortices to develop. These vortices resemble elongated streaks having alternate spanwise variations of the streamwise velocity. Following the transient growth phase, the fully developed vortex structures downstream undergo an inviscid secondary instability mechanism and, ultimately, transition to turbulence. This mechanism becomes much more complicated in high-speed boundary layer flows due to compressibility and thermal effects, which become more significant for higher Mach numbers. In this research, we formulate and test an optimal control algorithm to suppress the growth rate of the aforementioned …

Development Of Load Measurement Technique For Arbitrary Shapes, Quintin J. Cockrell

Master's Theses

Obtaining aerodynamic forces and moments about all three orthogonal axes for arbitrary shapes at arbitrary orientations in a fast manner via a measurement technique specific to Cal Poly’s low-speed wind tunnel to continually obtain the forces and moments under quasi-steady conditions is explored. A Continuous Rotation Technique (CR) uses a 6-DOF load cell and stepper motor to rotate an object about an axis for a complete rotation. The forces and moments acting upon the object pass through the stepper motor and interface plates and recorded by the load cell as the object is rotated continuously a finite number of rotations. …

Husker Motorsports Active Drag Reduction System, Creighton Hughes, Evan Killian, Micah Busboom, Aj Johnson, Jude Steffen

Honors Program: Senior Projects (Public)

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 …

Parametric Optimization Of A Wing-Fuselage System Using A Vorticity-Based Panel Solver, Chino Cruz

Master's Theses

Aerodynamic topology optimization is a useful tool in the aerodynamic design pro-
cess, especially when looking for marginal gains within a design. One example is
a turboprop racer concept aircraft that is designed with the goal of breaking world
speed records. An optimization framework was developed with the intention of later
being applied to this design. In the early design stages, the optimization framework
must focus on quicker methods of drag estimation, such as a panel codes. The large
number of design variables in topology optimization can exponentially increase func-
tion evaluations and thus computational cost. A vorticity-based panel solver …

Numerical Investigations Of Sco2 Compressor Aerothermodynamics Using A Streamline Curvature Based Throughflow Method, Victor Quintanilla

UNLV Theses, Dissertations, Professional Papers, and Capstones

Supercritical carbon dioxide (sCO₂) has emerged as a promising working fluid for the Brayton power cycle, offering enhanced efficiency due to the high density and low viscosity of carbon dioxide (CO₂) near the critical point. A critical component of the sCO₂ Brayton cycle is the turbomachinery, namely the compressor, which significantly contributes to the efficiency enhancement in the sCO₂ Brayton cycle owing to reduced compression work requirements. Its primary function involves elevating the fluid's pressure, effectively priming it for the subsequent heat addition process from a thermal energy source. However, despite its advantages, challenges …

A Dynamic Scoring Methodology For Morphing Airfoil Designs With Application To A Stalling Scenario, Stone Wachs

UNLV Theses, Dissertations, Professional Papers, and Capstones

Shape Changing Airfoils (SCAs) are a developing technology with potential aircraft applications. Leading aerospace corporations are actively researching SCA capabilities. The necessity for this technology stems from the requirement of control surfaces for safe aircraft control. However, the process of testing and determining optimal SCA designs can be costly and time-consuming. While methodologies exist, they often require specific scenario examples and lack a standard approach. To address this issue, a standardized methodology is needed that can be applied to various applications and scenarios. This methodology consists of computational/experimentally produced data for airfoils, a subjective and strategic scoring equation, an algorithmic …