Aerospace Engineering Commons^™

Structural Optimization And Reliability Assessment Of Heterogeneous 3d Ic Packages And Analysis Of Rheological Properties Of Particle Based Thermal Interface Materials, Mehzabeen Binte Kabir

Mechanical and Aerospace Engineering Theses - Archive

As computing and communication devices are converging with improved functionally, denser, and finer pitch which creates complexity of circuit interconnections for 2-D devices becomes a limitation for overall performance and drives up power dissipation [1]. Thus the ordinary 2-D structures of IC packages cannot address those demands where 3-D through-silicon via (TSV) is the key to 3-D IC integration and stacking of chips, is emerging now as a powerful tool to converge the needs of integrated circuit (IC) packages. In 3D TSV the chips are stacked on top of another so heat trapped in a small region which is difficult …

Sensitivity And Estimation Of Aerodynamic, Propulsion, And Inertial Parameters For Rudderless Aircraft Using Simulation, Jaden W. Thurgood

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A technique known as system identification is often used in aircraft design and testing to understand and validate the mathematical parameters that describe the aircrafts stability and handling characteristics. System identification can be thought of as the inverse of simulation. In the world of system identification, we have a physical system that we seek to understand in more detail by monitoring the system with an array of sensors. In short, we conduct tests of an aircraft while recording the inputs and response outputs. Then we take the input and output data and run it through an algorithm that seeks to …

Air Navigation And Covid-19: Atm Efficiency In Pandemic Crisis, Fabio Lourenco Carneiro Barbosa

Graduate Student Works

The coronavirus crisis effects on aviation in 2020 are currently well-documented. Nonetheless, the widely registered low traffic due to the crisis does not necessarily lead to increased air navigation efficiency. Thus, the present work, developed to fulfill the program outcomes for the Master of Science in Aeronautics, Air Traffic Management (ATM) specialization, aimed to investigate what was the impact of the COVID-19 crisis on air navigation efficiency in Brazil. This research question was addressed through a quantitative, nonexperimental, observational approach with two parallel branches, designed to answer two sub-questions. For the first, regarding what was the impact of the crisis …

Spatial Coherence Of Low-Frequency Unsteadiness Associated With A Normal Shock Wave, Matthew Cox, Phillip M. Ligrani, Kyle Goethals

PRC-Affiliated Research

The present data illustrate a unique analysis approach to explore the physics of shock-wave-flow interactions, based upon correlation and spectral analysis of digitized shadowgraph visualization time-sequence data. As such, demonstration is provided of the use of high resolution, flow visualization data for quantitative correlation and spectral analysis. A shadowgraph system is employed to visualize time-varying, shock wave flow features within the test section of one leg of the transonic/supersonic wind tunnel (which is also referred to as the SS/TS/WT or SuperSonic/TranSonic/WindTunnel), located within the Propulsion Research Center of the University of Alabama in Huntsville. Of interest is a flow field …

Spatial Coherence Of Low-Frequency Unsteadiness Associated With A Normal Shock Wave, Matthew Cox, Phillip M. Ligrani, Kyle Goethals

PRC-Affiliated Research

The present data illustrate a unique analysis approach to explore the physics of shock-wave-flow interactions, based upon correlation and spectral analysis of digitized shadowgraph visualization time-sequence data. As such, demonstration is provided of the use of high resolution, flow visualization data for quantitative correlation and spectral analysis. A shadowgraph system is employed to visualize time-varying, shock wave flow features within the test section of one leg of the transonic/supersonic wind tunnel (which is also referred to as the SS/TS/WT or SuperSonic/TranSonic/WindTunnel), located within the Propulsion Research Center of the University of Alabama in Huntsville. Of interest is a flow field …

On The Computational Efficiency Of Les And Hybrid Rans-Les Models In Building Aerodynamics, Aly Mousaad Aly, Faiaz Khaled

Faculty Publications

Large-eddy simulation (LES) has proven to offer superior accuracy in regards to predicting surface pressures compared to the Reynolds-averaged Navier Stokes (RANS) models. However, the primary impediment is the high computational cost associated with LES. The authors attempt to investigate the computational cost and accuracy by employing different sub-grid scale (SGS) models in LES and hybrid RANS-LES models. One of the prerequisites of accurate pressure estimations is to ensure a horizontally homogeneous empty computational domain. This study aims to compare the computational competence qualitatively and quantitatively using an empty domain in regards to the ability to maintain horizontal homogeneity. The …

Improving The Impingement Cold Plate Thermal Design Using Numerical And Analytical Approach, Reuben Joshua Madhuker

Mechanical and Aerospace Engineering Theses - Archive

Conventional cooling methods for an IC chip uses heat spreader to transfer heat from the chip end of the spreader to the opposite end of the spreader which then uses air or water to remove heat and thereby maintaining the overall temperature. Unfortunately, the heat spreader itself has constraints such as conduction resistance which adds the heat spreader inefficiency. But if we increase the area exposed to the cooling end then this can be improved. This is done by introducing channels at that end. These channels act as fins which give a better shot at cooling the system temperature. These …

On The Computational Efficiency Of Les And Hybrid Rans-Les Models In Building Aerodynamics, Faiaz Khaled, Aly Mousaad Aly

Faculty Publications

No abstract provided.

Characterizing High Entropy Alloys For Hypersonic Applications, Katherine Pettus

Mechanical Engineering Undergraduate Honors Theses

In this paper, the properties of a new and broad class of materials, high entropy alloys (HEAs), were investigated and evaluated for hypersonic applications. The plan was to identify candidate hypersonic HEAs and model the high-temperature strength using new advanced material models that account for asymmetry and anisotropy characterized with available test data. After accessing a local database of HEAs and their material properties in collaboration with Dr. Gorsse et al., it was realized the knowledge of HEAs is currently very broad but lacks depth. While hundreds of HEAs have been created and tested, none so far have both sufficient …

Improving The Performance Of An Ead Aircraft By Use Of A Retractable Electrode System, Michael Alexander Fredricks

Mechanical Engineering Undergraduate Honors Theses

Electroaerodynamic (EAD) propulsion is a growing area of research for small, low powered aircraft. Recent tests of EAD aircraft have demonstrated low performance in unpowered, gliding flight. The purpose of this paper is to investigate the effect of a retractable electrode system on the flight performance of an EAD aircraft. An analysis of electrode drag contribution on the MIT ionic wind plane’s performance predicts a maximum lift to drag ratio of 22, with the addition of a retractable electrode system, for a similarly sized and modeled EAD aircraft. An experiment is developed using a prototype aircraft, launcher, and retraction system …

Analysis On Fuel Options For Scramjet Engines With The Study To Lower The Starting Mach Number, Sumantra Luitel, Gagan Dangi

Honors Theses

The main objectives of this report were to perform analysis of an ideal scramjet engine, to assess the influence of fuel on endurance factor, and the possibility of lowering the starting Mach Number of the scramjet. In the first part, an ideal cycle parametric analysis was conducted on three different fuels i.e. Liquid Hydrogen (LH2), Jet Propellant 7 (JP-7), and Rocket Propellant (RP-1), taking into account their availability, physical properties, current uses, and potential uses. The detailed analysis is done largely relying on a 9 step Parametric Cycle Analysis technique to study how fuel properties influence the variation of seven …

2021 Spring Graduate Recognition Program, Propulsion Research Center, Robert Frederick

PRC Graduate Recognition

This program includes the graduate recognition program for spring 2021. Includes photographs, upcoming events, recent publications, and student profiles.

Foundations For The Coupled Inflow And Structural Dynamics Of Multi-Rotor Helicopters, Ethan Genter

McKelvey School of Engineering Graduate Student Theses & Dissertations

In this work, the Peters-Seidel finite-state model is expanded to calculate the coupled inflow and rotor dynamics of tandem rotor configurations. This establishes the foundation for a more complete multi-rotor, dynamic inflow model with finite-state methods. The derivation presented in this work is for the general case of two rotors in the same plane, overlapping and separated to varying degrees. It is the purpose of this work to study the unique and interesting dynamics and characteristics of various tandem systems heretofore not studied in a dynamic system. Moreover, it is the goal of this work to investigate how these systems …

Plasma Aerodynamics: Experimental Quantification Of The Lift Force Generated On An Airfoil Using Plasma Actuation To Estimate Power Requirements In Small Uav Applications, Getachew Ashenafi

UNLV Theses, Dissertations, Professional Papers, and Capstones

This research addressed the amount of electric power required to induce specific changes in lift force using a NACA 2127 airfoil with a chord length of ~28 mm, connected to a micro load cell, in a wind tunnel of 103 square centimeter cross-section. A DBD plasma actuator supplied by a ZVS driven high voltage pulsed DC circuit, operating at a frequency of 17.4 kHz, was utilized for voltages of up to 5000 V. Two configurations of electrode gapping were compared to determine the efficient use of power. The configuration with a gap of ~1 mm between the upstream and downstream …

Sonic Boom Loudness Reduction Through Localized Supersonic Aircraft Equivalent-Area Changes, Troy A. Abraham

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The NASA University Leadership Initiative (ULI) titled “Adaptive Aerostructures for Revolutionary Civil Supersonic Transportation” looks to study the feasibility of distributed structural adaptivity on a supersonic aircraft for maintaining acceptable en-route sonic boom loudness during overland flight. The ULI includes a team of industry and university partners that are working together to develop and implement the systems necessary to accomplish this goal.

The Utah State University Aerolab is a member of this ULI team and has been tasked with developing and using low-fidelity supersonic aerodynamic and sonic boom predictions tools to rapidly study the effects of localized geometry changes on …

Computational Fluid Dynamics Benchmark Validation Experiment Of Plenum-To-Plenum Flow Through Vertical Heated Parallel Channels, Austin W. Parker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The next generation of nuclear power plants will have higher efficiency and improved safety, among other benefits; one attractive option is the high temperature gas reactor. An ability to predict the physics that occur within the reactor under normal conditions and accident scenarios is necessary before it receives regulatory licensing for use. The flow through a high temperature gas reactor involves complex interactions of heat transfer, fluids, and solids.

One method for simulating complex fluid dynamics is called Computational Fluid Dynamics. These simulations have already been used to predict the complex fluid flows found in high temperature gas reactors. Predicting …

Air Traffic Controllers’ Occupational Stress And Performance In The Future Air Traffic Management, Hui Wang

Doctoral Dissertations and Master's Theses

As demand for unmanned aerial vehicle (UAV) operations increases, it is vital to understand its effects on air traffic controllers and the safety of the national airspace system. This study’s primary purpose is to determine how UAVs that operate in controlled airspace would influence air traffic controllers’ occupational stress and performance. In a within-subject experimental research design, 24 participants sampled from a university’s undergraduate Air Traffic Management (ATM) program completed three different air traffic control (ATC) scenarios on an en route ATC simulation system. The degree of UAV automation and control were varied in each scenario. The participants’ stress levels, …

Computational Investigation Of Perforated Plate Film Cooling Utilizing Conjugate Heat Transfer, Jonathan Sippel

Doctoral Dissertations and Master's Theses

The accuracy of modern state-of-practice computational fluid dynamics approaches in predicting the cooling effectiveness of a perforated plate film-cooling arrangement is evaluated in ANSYS Fluent. A numerical investigation is performed using the Reynolds Averaged Navier Stokes equations and compared to NASA Glenn’s available Turbulent Heat Flux 4 experimental measurements collected as a part of the Transformational Tools and Technologies Project. A multiphysics approach to model heat conduction through the solid geometry is shown to offer significant improvements in wall temperature and film effectiveness prediction accuracy over the standard adiabatic wall approach. Additionally, localized gradient-based grid adaption is analyzed using the …

Analysis Of Ship Airwakes Using Modal Decomposition, Nicholas Zhu

Doctoral Dissertations and Master's Theses

The three-dimensional, unsteady, and turbulent airwake produced by a scaled model of a generic Navy ship (Simple Frigate Shape No. 2) was investigated in a low-speed wind tunnel. Stereoscopic, time-resolved particle image velocimetry (TR-PIV) measurements were made at six different crosswise planes over the flight deck region of the ship model, with and without the effect of a simulated atmospheric boundary layer (ABL).

Spatiotemporal analyses of the TR-PIV measurements were performed using modal decomposition, and the modes were decomposed further based on the frequency contents of their time dynamics. This approach allowed an inspection of the individual scales of the …

Adaptive Control For Nonlinear, Time Varying Systems, John Zelina

Doctoral Dissertations and Master's Theses

It is common for aerospace systems to exhibit nonlinear, time varying dynamics. This thesis investigates the development of adaptive control laws to stabilize and control a class of nonlinear, time varying systems. Direct adaptive control architectures are implemented in order to compensate for time varying dynamics that could, for example, be caused by varying inertia resulting from fuel slosh or settling in a tank. The direct adaptive controller can also respond to external disturbances and unmodeled or nonlinear dynamics. Simulation results are presented for a prototype system that consists of two rotating tanks with time varying inertia due to the …