Aerodynamics and Fluid Mechanics Commons^™

Lip Thrust Apparatus, Ian M. Wilson, Alvin K. Cheong

Mechanical Engineering

This document contains the background information, defined scope of work, preliminary design philosophy, conceptual design development, and final design choices along with its corresponding manufacturing and design verification plans. It also includes the preliminary testing and prototyping necessary in bringing our verification prototype to its final configuration for delivery. Finally, it includes the entire manufacturing process followed in creating the final project and the extensive testing performed to ensure it meets the defined engineering specifications. The aerodynamic phenomenon being analyzed and demonstrated in our final deliverable can be seen in a scenario where when a propeller is enclosed in a …

The Effect Of Passive And Active Boundary-Layer Fences On Delta Wing Performance At Low Reynolds Number, Anna C. Demoret

Theses and Dissertations

The effect of passive and active boundary-layer fences (BLFs) on performance is evaluated on a NACA 0012 delta wing (c_root = 14in, c_tip = 2.8in, Λ = 45°, b = 23.5in) at a Reynolds number (Re) of 5.0 x 10⁵ based on the root chord. The performance improvements of a passive BLF are replicated and improved upon using an active flow control (AFC) fluidic fence created by a wall-normal steady-blowing jet from a slot. The application of a passive BLF at a spanwise location of 70% z/b resulted in an 8.7% increase in C_Lmax compared to …

Characterization Of Inertial Particles In The Turbulent Wake Of A Porous Disk, Kristin Nichole Travis

Dissertations and Theses

This study presents the findings of a wind tunnel experiment investigating the behaviour of micrometric inertial particles in the turbulent wake of a stationary porous disk. Various concentrations [Φ_v ∈ (2.95 x 10^-6 - 1.22 x 10^-5)] of polydisperse water droplets (diameter 13-41 µm) are compared to sub-inertial tracer particles. Hot-wire anemometry, phase Doppler interferometry and particle image velocimetry were implemented in the near and far wake regions to study the complex dynamics of the particles. Turbulence statistics and particle size distributions are presented and used to explore the particle wake interaction.

High Order Explicit Semi-Lagrangian Method For The Solution Of Lagrangian Transport And Stochastic Differential Equations, Hareshram Natarajan

CGU Theses & Dissertations

A semi-Lagrangian method is developed for the solution of Lagrangian transport equations and stochastic differential equations that is consistent with Discontinuous Spectral Element Method (DSEM) approximations of Eulerian conservation laws. The method extends the favorable properties of DSEM that include its high-order accuracy, its local and boundary fitted properties and its high performance on parallel platforms for the concurrent semi-Lagrangian and Eulerian solution of a class of time-dependent problems that can be described by coupled Eulerian-Lagrangian formulations. Such formulations include the probabilistic models used for the simulation of chemically reacting turbulent flows or particle-laden flows. Motivated by the high-fidelity simulation …

Design Of Banner Tow Mechanism For Bush Plane, Kyle Ciarrone, Ivan Martin, Rishabh Gadi, Tyler Brandt

Williams Honors College, Honors Research Projects

The 2019-2020 AIAA DBF objective was to design, build, and test a banner-towing bush plane that carries wooden passengers and luggage. Senior members on the team undertook the creation of the banner tow mechanism subsystem as their senior design project on behalf of the design team due to the challenge of its mechanical design and the aerodynamic considerations regarding its placement and enclosure aboard the aircraft. The competition as well as access to campus resources were canceled due to COVID-19, so full testing and integration of the mechanism was not achieved. However, the engineering design process was experienced from the …

Study Of Non-Ideal Effects On Shock Wave Propagation, Cory Kinney

Electronic Theses and Dissertations, 2020-2023

Shock tube experiments provide insightful data on combustion, emissions, and ablation characterization for a wide variety of defense and energy sector research topics. Accurate characterization of shock tube facilities is essential to verifying the accuracy of research data. Non-ideal effects, such as boundary layer growth, introduce uncertainty into pressure and temperature conditions, the primary independent variables of interest for shock tube research results. The effect of boundary layer growth on shock tube experiments was investigated by conducting simulations for University of Central Florida's two geometrically different shock tube using StanShock, a quasi-one-dimensional, reacting, compressible flow solver. The characteristic quantities considered …

A Study Into Validating A Coupled Method Of Characteristics And Direct Simulation Monte Carlo Method Against Empirical Data, Andrew Brown

Electronic Theses and Dissertations, 2020-2023

The following will outline the methodology and results of validating a coupled Method of Characteristics (MOC) and Direct Simulation Monte Carlo (DSMC) method. This research focused specifically on modeling plume impingement, induced by Reaction Control System (RCS) thrusters that flew on the National Aeronautics and Space Administration's (NASA's) space shuttle Discovery. For each simulation, the continuum portion of the RCS thruster was simulated using MOC for solving hyperbolic Partial Differential Equations (PDEs) and computed with the NASA code, Reacting and Multi-phase Program (RAMP). The solution was then implemented as a starting condition into the NASA DSMC code, Direct Simulation and …

Active Fault-Tolerance Of The Unmanned Aerial Vehicle Automatic Control Systems, Vuong Anh Trung, Nguyen Van Thinh, Nguyen Duc Thanh, Nguyen Quang Vinh, Tran Thuan Hoang

International Journal of Aviation, Aeronautics, and Aerospace

This paper presents an introductory overview of principles of the three-layer hierarchy of active fault-tolerance, providing, determination of the fault type with as many details as enough to get recoverable fault reason and failure toleration by flexible redundancy using; the conception of active fault-tolerant control in abnormal modes is described. Developed models and methods of a systematic approach to fault tolerance in the direction of the effective use of the signal, parametric and structural redundancies and selection of parrying tools. Performed experimental researches of the unmanned aerial vehicle (UAV) automatic control systems (ACS).

Design And Visual Servo Control Of A Mechanical Gripper For Autonomous Strawberry Harvesting, Jonah Mapes

Electronic Theses and Dissertations, 2020-2023

With rising labor costs and high consumer demand, economic conditions are becoming increasingly favorable for mechanization in the strawberry industry. However, virtually all strawberry crops are still picked by hand because the harvesting process is very challenging to automate, and strawberries are susceptible to bruising. For these reasons, the development of a harvester which can avoid damaging the fruit is of interest. Conventional designs for robotic grippers are less than ideal, as precise positioning or force feedback capabilities are required to reduce the risk of bruising. As an alternative, a novel "camera-in-hand" gripper design is presented which effectively avoids bruising …

A Cfd Study Investigating Drag Reduction For Different Offset And Inline Distance For Two Trucks Platooning, Wael Mokhtar, Kyle Dinger, Shardul Kachare, Mdrazib Hossain, Colin Britcher

Mechanical & Aerospace Engineering Faculty Publications

The automotive industry invests huge resources to improve fuel consumption of commercial vehicles by improving their aerodynamic efficiency. Recently, numerous studies investigating the effect of platooning on aerodynamic drag of semi-trucks have been performed by researchers indicating a positive impact. For the present study, a three-dimensional computational study was performed to investigate the effect of varying offset and linear distance during platooning on the total drag of two semi-trucks. The study was conducted on a full-scale model using Reynold’s Averaged Navier-Strokes governing equations for a moving ground simulation using the STAR-CCM+ computational package. Furthermore, for turbulence, the standard k- …

The Use Of Polyvinyldene Fluoride (Pvdf) Films For Pressure Measurement, Patrick Smith

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Toward Adjoint-Based Aeroacoustic Optimization For Propeller And Rotorcraft Applications, Ramiz Ö. Içke, Oktay Baysal, Andy Moy, Leonard V. Lopes, Beckett Zhou, Boris Diskin

Mechanical & Aerospace Engineering Faculty Publications

The goal of the present project is to build a multidisciplinary, rapid, robust, and accurate computational tool to optimize wing-mounted propeller designs. The full Farassat’s formulation F1A for aeroacoustic analysis is implemented in the open-source software SU2. This extension enables the prediction of far-field noise generated by moving sources. The formulation is verified, for a stationary and rotating sphere in a wind tunnel and for a tiltrotor in forward flight, by comparing the acoustic predictions of SU2 with the predictions computed by NASA’s aeroacoustics code ANOPP2. The algorithmic differentiation capability of SU2 provides discretely consistent, adjoint-based sensitivity analysis for this …

Evaluation Of Convective Heat Transfer Numerical Methods On Rough Surfaces From Additive Manufacturing, Jose Urcia

Electronic Theses and Dissertations, 2020-2023

The high versatility of additive manufacturing has led to an increase in use in a number of different fields. Surface roughness then comes as a natural consequence of additive manufacturing which interferes with a smooth wall assumption such as those found in gas turbine blades. The Discrete Element Roughness Method (DERM) has been used to improve convective heat transfer predictions on surface roughness. This work aims to validate the core momentum and heat transfer correlation of DERM through an evaluation of Computational fluid dynamics (CFD)-based solution of the flow around individual roughness elements with the goal of improving the correlations. …

Flame Stabilization Of A Premixed Jet In Vitiated Coflow, Tyler Owens

Theses and Dissertations--Mechanical and Aerospace Engineering

Premixed staged combustion in gas turbine engines can reduce emissions by lowering peak flame temperatures but can also lead to different stability characteristics when compared to traditional combustors. High pressure ratio and subsequently high temperatures can lead to conditions suitable for both autoignition and premixed flame propagation in an environment where spatial fuel/air variations are present.

An experimental facility which issues a premixed jet into a coflowing vitiated mixture was studied to examine the stability behavior, resulting in a lifted flame. The effective ignition delay observed flame was much greater than homogeneous ignition delay calculations for the same conditions. It …

Development Of Universal Solver For High Enthalpy Flows Through Ablative Materials, Umran Duzel

Theses and Dissertations--Mechanical and Aerospace Engineering

Atmospheric entry occurs at very high speeds which produces high temperature around the vehicle. Entry vehicles are thus equipped with Thermal Protection Systems which are usually made of ablative materials. This dissertation presents a new solver that models the atmospheric entry environment and the thermal protection systems. In this approach, both the external flow and the porous heat shield are solved using the same computational domain. The new solver uses the Volume Averaged Navier-Stokes Equations adapted for hypersonic non-equilibrium flow, and is thus valid for both domains. The code is verified using analytical problems, set of benchmarks and also a …

Rocket Motor Nozzle, Corey Hillegass

Williams Honors College, Honors Research Projects

For this honors research and senior design project, the authors will research, analyze, and manufacture a rocket motor nozzle for the Akronauts rocket design team. This research and design project will improve how the rocket design team will decide and manufacture nozzles going forward. The impact of this improvement allows the rocket design team to take steps toward being self-sustaining by manufacturing student designed parts as opposed to commercially bought parts. This will not only be successful in increasing student impact on future designs, but also provides a technical challenge for the authors and will present as an impressive feat …

Experimentation And Simulation Of Pulsed Eddy Current Thermography Of Subsurface Aircraft Corrosive Defects, Johnathan Hernandez

Electronic Theses and Dissertations, 2020-2023

During the life cycle of aircraft, external structures are under constant attack from environmental degradation in the form of corrosion. Corrosive defects consist of multiple types of surface and subsurface damage that are often undetectable due to surface coatings or insulation leading to loss in structural integrity. Non-destructive techniques for corrosion detection typically require the removal of paint. Detection of corrosion under insulation (CUI) is highly valuable for cost and time effectiveness. Although techniques have been developed for detection of CUI, not many of these satisfy the criteria for portability and hangar operation. To address this, multiple techniques were investigated …

Efforts In Numerical Modeling Of Undulating Propulsion, George Loubimov

Electronic Theses and Dissertations, 2020-2023

Naval propulsion is a critical component for every vessel, and it is the subject of this thesis, specifically bio-inspired propulsion. Numerical modeling is used as a tool to understand the relationship between mechanical undulation and the hydrodynamic response. Through three stages, the research presented here examines and refines tools for understanding fundamentals of undulating propulsion. Those three objectives are: to verify and validate the proposed numerical models against existing experiments, establishing a baseline of fidelity; to examine the causal linkage between fluid-boundary interactions and undulating propulsion; and to create a moment based method for characterizing generalized undulating propulsive mechanisms. First, …

Supersonic Propulsion: Inlet Shock Wave/Boundary Layer Interaction In A Diffuser, Lucas Fulop, Ian Henry, Jordan Ruffner, Anthony Mcmullen

Williams Honors College, Honors Research Projects

Using a finite-volume approach and ANSYS/FLUENT, supersonic flow over a 2-D ramp of varying angles is modeled. The computational results from this model will be used to further explore the design of supersonic diffusers used on military aircraft. Using grid capturing features and inflation layers, shockwave and boundary layer interactions will be observed as well as wave-associated pressure changes in supersonic turbulent flow. The Spalart-Allmaras single-equation model of turbulent flow will be used in all simulations to more accurately represent the phenomena that occur in such high-speed environments. The size of upstream zones and recirculation zones will be obtained through …

Thermal / Structural Analysis Of The Hb 650 Thermal Shield, Gerald J. Smith

Graduate Research Theses & Dissertations

Fermilab’s PIP-II project’s superconducting linear accelerator (Linac) will drive the next generation of particle accelerators through a revolution in beam intensity. Key to beam intensification are the high efficiencies of niobium-tin superconducting radiofrequency (SRF) cavities operating at cryogenic temperatures near 5 Kelvin. A multifaceted approach is employed to achieve and maintain the extreme temperature. Vacuum provides the first barrier to thermal convection. Physical thermal intercept zones further isolate the exterior shell vacuum vessel at 300 Kelvin from the supercooled beamline. The first thermal intercept lies just inside the exterior vacuum vessel forming the 40 Kelvin zone. This 40K thermal shield …