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Articles 1 - 14 of 14

Full-Text Articles in Aerodynamics and Fluid Mechanics

Influence Of The Sst K-Ω Stress-Limiter Coefficient On Transonic Shock Buffet Prediction For The Oat15a Supercritical Airfoil, Melinawo Vowotor Jan 2026

Influence Of The Sst K-Ω Stress-Limiter Coefficient On Transonic Shock Buffet Prediction For The Oat15a Supercritical Airfoil, Melinawo Vowotor

College of Graduate Studies: Theses & Dissertations

Transonic shock buffet predictions using the Shear Stress Transport (SST) k–ω turbulence model are known to be sensitive to the stress-limiter coefficient a₁, yet no systematic investigation of this sensitivity exists. This thesis presents a parametric study of a₁ for two-dimensional URANS simulation of shock buffet on the OAT15A supercritical airfoil at M = 0.73 and Re = 3 × 10⁶. Eleven a₁ values (0.25–0.37) are examined at α = 3.5°, and a matrix of five a₁ values across five angles of attack (3.0°–3.9°) maps the interaction with incidence. The results reveal that a₁ acts as a bifurcation parameter: a …


Bio-Inspired Airfoil Design Based On The Aerodynamic Analysis Of A Bird Feather Microstructure, Jack C. Ihm Jan 2025

Bio-Inspired Airfoil Design Based On The Aerodynamic Analysis Of A Bird Feather Microstructure, Jack C. Ihm

College of Graduate Studies: Theses & Dissertations

This study investigates the aerodynamic effects of a bio-inspired airfoil design based on the microstructure of a secondary feather from a female wood duck. The research hypothesized that incorporating barbs and barbules into an airfoil design would modify boundary layer behavior by introducing localized flow disturbances. To test this, a bio-inspired airfoil was developed by integrating the microstructure into a NACA 0012 airfoil and analyzed using computational fluid dynamics (CFD) simulations at angles of attack of 0°, 5°, 10°, and 15°. The results showed that the bio-inspired airfoil influenced boundary layer behavior, producing localized flow disturbances near x/c = 0.7 …


Hybrid Rans-Les Analysis Of Turbulent Flame Under Near Blow-Off Condition In A Multi-Stage Swirl Combustor, Brandon O'Brien Jan 2025

Hybrid Rans-Les Analysis Of Turbulent Flame Under Near Blow-Off Condition In A Multi-Stage Swirl Combustor, Brandon O'Brien

College of Graduate Studies: Theses & Dissertations

Advances in computational resources are making computational fluid dynamics (CFD) increasingly accessible for a variety of engineering applications. However, certain complex problems, such as simulating detailed flame kinetics, remain computationally prohibitive for many users. Developing cost-effective methods to simulate these challenges would greatly benefit applications involving flame dynamics, such as turbine engines or industrial burners. This study investigates the effect of main stage swirler intensity on near lean blow-off characteristics in a multi-staged swirl combustor using Ansys Fluent. The hybrid RANS-LES turbulence model, Stress Blended Eddy Simulation (SBES) coupled with Flamelet Generated Manifold (FGM) combustion model was selected to model …


Aerodynamic Design And Analysis Of A Modified 2006 Mazda Miata, William N. Recher Apr 2024

Aerodynamic Design And Analysis Of A Modified 2006 Mazda Miata, William N. Recher

Honors College Theses

Aerodynamic forces developed by automobiles have destabilizing effects at high speed. These forces tend to skew toward a vehicle’s rear which can present safety concerns, especially for rear-wheel-drive automobiles like the Mazda Miata. To address oversteer and high-speed instability, a vehicle’s design can be tailored to bring about aerodynamic balance and improve traction. LiDAR was used to bring the physical automobile into the digital space. Then, a splitter and diffuser were added to reduce the magnitude of the destabilizing forces. Next, the size and shape of the rear-wing required to balance the vehicle was calculated using a combination of parameters …


Aerothermodynamic Analysis Of A Linear Aerospike Fueled With Liquid Methane Using Cfd, Aidan Rowell Jan 2024

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 …


Implementation Of Cavity Vortex Generators To Mitigate Stall And Ice Accretion On The Naca 0012, Eric Pernell Jan 2024

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 …


Computational Analysis Of A Naca 0012 Straight Wing At Various Reynolds Numbers Approaching Stall, John E. Crowe Iii Jan 2024

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 …


Experimentatal And Numerical Investigation Of Turbojet Engine Performance, Emissions, And Noise/Vibrations Using Jet-A And F24 Fuel, John W. Mcafee Jr Jan 2024

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 …


Aeroelastic Phenomena Of Fixed-Wing Aircraft In Transonic And Supersonic Flows Using A Tightly-Coupled Computational Approach, John C. Havenar Jan 2024

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 …


Mitigation Of Aeroacoustic Noise Of A Fixed Wing Using Passive Flow Control, Cameron L. Perry Jan 2023

Mitigation Of Aeroacoustic Noise Of A Fixed Wing Using Passive Flow Control, Cameron L. Perry

College of Graduate Studies: Theses & Dissertations

As the world becomes more environmentally conscious, noise pollution is of increasing concern. In this study, shallow dimples are applied to a NACA 0012 airfoil at multiple angles of attack (AoA) with the intent of reducing aeroacoustic noise emissions. Both Reynolds Averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES) models are used for aerodynamic and aeroacoustic investigations, respectively, at a fixed Reynolds number of 4.8 x 105. Altering the dimple depth to diameter ratio (d/D) from 2.5% to 15% is first investigated, with a d/D of 5% or lower resulting in the least aerodynamic impact. The transition from …


Computational Comparison Of Dual Bell, Expansion-Deflection, And Aerospike Nozzles, Manuel R. Abadie Ardon Apr 2022

Computational Comparison Of Dual Bell, Expansion-Deflection, And Aerospike Nozzles, Manuel R. Abadie Ardon

Honors College Theses

In the search for a Single-Stage-to-Orbit rocket, Altitude Compensating Nozzles concepts (ACNs) have been proposed since the 1950s, but research has stalled despite the modern analysis tools available. These nozzle concepts offer optimum performance at two or more altitude settings. This research chose three of these concepts, these being the Dual Bell, Expansion-Deflection, and Aerospike, which were designed and analyzed at various pressure ratios (NPR=10,15,30,36,30,45) using Computational Fluid Dynamics (CFD) software FLUENT. Simulations generated pressure distributions along the nozzle wall, which allowed to calculate data values such as thrust coefficients. Nozzle efficiency is calculated from this data and used to …


Comparative Analysis Of Winglet Efficiency On Supercritical Versus Traditionally Cambered Airfoils, Evan Cathers Jan 2022

Comparative Analysis Of Winglet Efficiency On Supercritical Versus Traditionally Cambered Airfoils, Evan Cathers

College of Graduate Studies: Theses & Dissertations

This study serves to define the performance of several industry-recognized and exploratory wing tip devices on aircraft wings utilizing contemporary supercritical airfoil geometry. For comparison, the same examination is performed on a wing comprised of traditionally cambered airfoils, the platform upon which winglets were initially developed. The supercritical wing design is based on that of the Airbus A320, while the conventional airfoil is based upon the Boeing 737-800 platform. Tip devices selected for analysis include blended, raked, split scimitar, fence, and spiroid winglets, as well as tip sails, characterized by the spreading of a bird’s primary flight feathers. Methodology for …


Cfd And Heat Transfer Analysis Of Rocket Cooling Techniques On An Aerospike Nozzle, Geoffrey Sullivan Jan 2022

Cfd And Heat Transfer Analysis Of Rocket Cooling Techniques On An Aerospike Nozzle, Geoffrey Sullivan

College of Graduate Studies: Theses & Dissertations

In recent years the development of rocket engines has been mainly focused on improving the engine cycle and creating new fuels. Rocket nozzle design has not been changed since the late 1960s. Recent needs for reliable and reusable rockets, as well as advancements in additive manufacturing, have brought new interest into the aerospike nozzle concept. This nozzle is a type of altitude adjusting nozzle that is up to 90% more efficient than bell nozzles at low altitudes and spends up to 30% less fuel. Since the nozzle body is submerged in the hot exhaust gasses it is difficult to keep …


The Effect Of Fuel Injector Spacing, Angle, And Blowing Ratio On The Fuel Air Mixing Performance Of A Scramjet Engine, Jonathan R. Copeland May 2021

The Effect Of Fuel Injector Spacing, Angle, And Blowing Ratio On The Fuel Air Mixing Performance Of A Scramjet Engine, Jonathan R. Copeland

Honors College Theses

In the operation of a Scramjet engine, which operates at hypersonic velocities, one of the most important factors is mixing the fuel and air before the high velocity air stream through the engine blows the mixture out of the engine before it could burn. Because of the importance of rapidly mixing fuel and air within a Scramjet engine, there are multiple design elements used to increase mixing. One of which is called a flame holder cavity, which is usually located behind fuel injectors, and designed with an open (length to depth ratio is less than 10) geometry to promote recirculation …