Aerodynamics and Fluid Mechanics Commons^™

Reduced Order Models Of Hydrodynamically Interacting Flapping Wings, Jose Pabon

Dissertations

Fish schools exhibit a collective behavior and self-organization that is mediated by hydrodynamic interactions between individual fish. However, the long-time evolution of hydrodynamically interacting collectives is challenging to investigate due to the persistent influence of long-lived vortical structures, and the high-resolution requirements of direct numerical simulation at large Reynolds numbers. Reduced-order models have therefore played an important role in theoretical investigations of collectives of swimming bodies. The main results detailed herein are several new reduced-order models of swimmers that self-propel by flapping, i.e., by executing a prescribed periodic rigid body motion. The models are extensions of a discrete-time dynamical system …

Analyzing The Impact Of Passive Techniques On Aircraft Wing Hysteresis: An Experimental And Numerical Study, Brendan Worton

Masters Theses

This study investigates the effects of passive flow control techniques on aerodynamic hysteresis primarily in NACA 2412 (cambered) and 0012 (symmetric) wings. Computational Fluid Dynamics (CFD) was used to design and evaluate three passive techniques, including outward-facing dimples, leading-edge tubercles, and rectangular vortex generators, prior to experimental validation. These techniques demonstrated improvements in aerodynamic performance in CFD simulations and were therefore selected for wind tunnel testing to analyze their aerodynamic performance and influence on hysteresis behavior. A custom, cost-effective experimental setup was designed and developed to facilitate efficient angle-of-attack control and data acquisition. It incorporates a three-axis force sensor, stepper …

Bio-Inspired Electroactive Polymer (Eap) Sensors For Surface And Canal Flow Sensing In Dynamic Environments, Nazanin Minaian

UNLV Theses, Dissertations, Professional Papers, and Capstones

Nature can often create some of the most efficient and elegant solutions to complex problems, and engineering stands to benefit greatly from these time-tested designs. One of the more sophisticated examples of this is the lateral line system in fish: a distributed network of superficial and canal neuromasts that enables aquatic species to detect fluid disturbances with remarkable precision. This dissertation leverages that biological framework to explore the potential of electroactive polymers (EAPs), aiming not just to replicate structure, but to emulate function.Two classes of EAPs form the basis of this work: electroactive plasticized polymer gels (EPPGs) and ionic polymer-metal …

Design Of A Fan-Based Test Stand For Evaluating Multicopter Handling In Turbulent Flow, Salim Roig

Doctoral Dissertations and Master's Theses

With the innovation of eVTOL rotorcraft the need to analyze how turbulence-induced disturbances from orthogonal flow affect various rotorcraft configurations outside of simulations have grown significantly. To investigate the behavior of this type of flow and how it interacts with various rotorcraft configurations, a turbulent inducing test stand was designed and constructed. The test stand will have two walls of computer fans arranged in an L-shape frame, creating wind gusts that simulate the non-linear turbulent wind experienced by eVTOL. This also aids the Eagle Flight Research Center (EFRC) in their efforts to better understand how disturbances affect the handling qualities …

Development And Application Of Novel Apparatus For Ocean Spray In Turbulent Atmospheres, Alicyn S. Koldewyn

All Graduate Reports and Creative Projects, Fall 2023 to Present

Ocean spray droplets can have significant effects including reducing surface heating from the sun, degrading air quality, and intensifying tropical cyclones. However, quantifying these effects has been challenging due to the multiscale, chaotic nature of wave breaking and turbulent flow. This research presents the development of a novel apparatus designed to combine bubble column droplet generation with synthetic jet actuators for turbulence generation. The purpose is to demonstrate reliable bubble formation and droplet generation, air turbulence effect on droplet dynamics, and quantitative measurement and analysis of these effects. The primary goals of the apparatus include optical accessibility for high-resolution imaging, …

Shock Induced Droplet Aerobreakup For Newtonian And Non-Newtonian Fluids, James Leung

LSU Doctoral Dissertations

This research investigates shock-induced aerodynamic breakup (aerobreakup) of fluids with different stress-strain behaviors. The central hypothesis is that shear stress from highspeed gas flow manifests differently depending on a fluid’s strain response, influencing droplet breakup morphology, fragment size distribution, and drag-induced acceleration. To test this, experiments and simulations were performed on μm–mm sized droplets of Newtonian (water) and shear-thinning fluids (nanofluids or xanthan gum). Two experimental setups were used: an open-ended shock tube and a closed conventional shock tube. In the openended setup, a normal shock impacts a stationary droplet held by an acoustic levitator. Droplet breakup and gas dynamics …

Implementing A 5-Dimensional Tabulated Conditional Moment Closure Model With Scalar Dissipation Rate For Scramjet Combustion, Alp Tuztas, Scott Montgomery Martin, Carlos A. Velez

Discovery Day - Daytona Beach

The growing interest in Scramjets for achieving sustained hypersonic flight has given rise to numerous computational models to obtain solutions as close as possible to experimental data, assisting with making the design process of modern Scramjet’s with different propellants and cavity designs less costly. However, Scramjet engines pose significant challenges for computational modelling due to the need of accounting for large- and small-scale turbulences but also solving turbulence chemistry interactions in compressible flow regimes. A promising approach has been through using high-fidelity turbulence-combustion models which greatly assist with capturing detailed chemistry, account for small scale turbulence and the complex flow …

Self-Regulated Thermal Management With Shape-Memory Alloy Torsional Tubes, Paula Sanjuan Espejo

Doctoral Dissertations and Master's Theses

The need for dynamic thermal management that adapts to varying system needs and requirements is a growing topic of interest in different engineering disciplines, most prominently aerospace and electronics. This demand for improved thermal management systems comes from the general increase of system efficiencies leading to an increase in component energy density. Shape-memory alloy actuators, which respond with a mechanical shape recovery to variations in temperature, can be used as self-regulated thermal management actuators that are able to respond to environmental thermal changes autonomously. In this dissertation, modeling and experimental analysis of a two-way shape-memory effect trained SMA torsional tube …

An Engineering Solution For Fan Aeroacoustics Measurements Correction In A Non-Anechoic Testing Environment, Saad-Eldin Taha, Mohamed Y.Zakaria, Mohamed Abdelgaied, M.M. Bassuoni Prof. Dr.

Journal of Engineering Research

Abstract- Nowadays, acoustic signatures of daily used applications are to be minimized. The study of noise generated through aerodynamic interaction with moving bodies has passed through different phases since the early 50s, and this leads to the evolvement of many analytical, empirical and computational techniques in order to be able to estimate the emitted noise. Concerning fan blades, until now the researches are still going for a reliable method for noise estimation during the early phases of design which help in the development of blades with a lower aeroacoustic signature, the Brooks, Pope and Marcolini (BPM) model was chosen to …

The Spectral Response Of Time-Resolved Piv In A Turbulent Boundary Layer, Peter Manovski, Wagih Abu Rowin, Henry Ng, Paul Gulotta, Matteo Giacobello, Charitha De Silva, Nicholas Hutchins, Ivan Marusic

Student Publications

This study presents the application of time-resolved particle image velocimetry (TR-PIV) to measure the mean and fluctuating velocity components in a turbulent boundary layer (TBL) over an axisymmetric body of revolution. A narrow wall-normal strip of the flow was captured using a synchronised high-speed laser and camera at a recording frequency of up to 80 kHz. The resulting streamwise and wall-normal velocity TR-PIV data were validated against hot-wire anemometry measurements and direct numerical simulations (DNS) of a flat plate under matched flow conditions. The mean flow results showed good agreement between all methods, while the expected attenuation due to the …

Thermally Perfect Augmentation Of A Supersonic Inlet Design Tool That Uses Method Of Characteristics, Mario V. Guardado

Master's Theses

This work is the first in a series to augment a supersonic air inlet design tool based in Python 3 to incorporate new models that increase the range of applicability of the tool. This effort focuses on improving the thermodynamics model by incorporating a thermally perfect gas model. This tool utilizes method of characteristics to solve the governing equations for an inviscid, irrotational, isentropic, steady, supersonic flow field. Multiple test cases are used to assess the accuracy of all new models. A comparison is made between the original code’s test case for a supersonic inlet at low temperatures to verify …

Data Driven Analysis Of Samara Seed Kinematics And Dynamics, Shashwat Sparsh

Master's Theses

Samara Seeds are a class of fruit most famously belonging to the Acer species and are characterized by their single-bladed geometry and their auto-rotation response during descent. This steady-state auto-rotation response is the subject of aerodynamic analysis which aim to quantify the performance. The period prior to the beginning of steady-state auto-rotation is classified as the transition regime and has not been the subject of intense scrutiny.

This thesis employs a data-driven approach to analyzing the kinematic and dynamic response of these seeds during both the transition and auto-rotation stages of flight to quantify the performance with respect to the …

Enhancement Of A Python Integral Boundary Layer Method, Jeffrey T. Azuma

Master's Theses

This thesis presents a series of additions to a Python based integral boundary layer software library known as PyBL. This library provides the user the means to calculate boundary layer properties using different models for boundary layer behavior. The additions feature the integration of a set of new laminar and turbulent integral boundary layer models originally developed for and currently found in the program XFOIL. These models were modified to fit the ODE solver method at the foundation of PyBL. A new method for PyBL that stitches a laminar and turbulent solution together has been developed to improve the ability …

An Inquiry Into The Physics Of Mixing And Floc Filtration, Andrew P. Pennock

Dissertations

Flocculation and clarification are two essential processes to deliver safe water at a reasonable cost to consumers. There are two major thrusts to the research presented in this dissertation. The first is to better characterize the physics and mixing parameters used for the design of hydraulic flocculators in the context of drinking water treatment plants. The second major thrust is to investigate floc filtration as a mechanism for the removal of primary particles during floc blanket clarification.

The intensity of mixing in environmental and chemical engineering applications is often characterized by the Camp and Stein velocity gradient. This parameter has …

Computational Fluid Dynamics Analysis Of A Turbine Blade, Luis Luna, Fabiha Samiha

Publications and Research

In Aerospace engineering, the use of computer-aided design (CAD) software, such as SolidWorks, is crucial when designing and validating high-performance parts. SolidWorks provides a valuable tool for simulating computational fluid dynamics (CFD), allowing engineers to analyze and visualize how parts behave under real-world aerodynamic conditions.

One such part is a turbine blade, an airfoil-shaped component inside a jet engine that compresses and redirects airflow to generate thrust. This study aims to perform aerodynamic testing of a single turbine blade design while evaluating SolidWorks' ability to simulate external flow conditions. By visualizing velocity profiles, pressure distribution, and vortex formation, the simulation …

Ultrafast Laser Surface Structuring For Wettability Control On Copper, Akshay Arvind Nagvenkar

All Theses

Wettability is a crucial surface property influencing various phenomena, including heat transfer, cell adhesion, and corrosion. Engineering devices can achieve superior performance by precisely manipulating surface wettability. As a result, extensive research has focused on developing surfaces that exhibit either extreme water attraction (superhydrophilic) or strong water repellency (superhydrophobic). Tailoring surface wettability paves the way for numerous applications, such as drag reduction in marine vessels, controlled drug delivery, efficient water collection, advanced liquid transport systems, oil-water separation, anti-corrosion coatings, friction reduction, and self-cleaning materials. Ultrafast laser surface structuring is a promising approach for engineering multifunctional surfaces, effectively modifying material properties …

Characteristics Of Patterned Surface Dielectric Barrier Discharge Devices For Ionic Wind Propulsion, Ethan J. Graef

Mechanical Engineering Undergraduate Honors Theses

Electroaerodynamic (EAD) or ionic wind propulsion is a growing area of research for small noiseless low speed aircraft. Previous flight demonstrations and experimentation have revealed that traditional methods of EAD propulsion utilizing corona discharge incur a large drag penalty due to their collector and emitter geometries. Recent publications detail flexible and geometrically conformable surface dielectric barrier discharge devices (SDBD) that could increase thrust and decrease drag as an ion source for an EAD propulsion system. This thesis explores the effects of different electrode sizes and geometries on total SDBD power consumption. SDBDs of a hexagonal, triangular, and square electrode geometry …

Micro Wind Turbine - Modelling And Testing, Mohammad Uzair Bhati

All Theses

The global energy demand continues to rise as people consume more electricity to power their personal electronics, electric vehicles, and consumer products such as outdoor tools. To generate renewable energy, large scale solar and wind farms continue to receive the most commercial attention. However, portable wind energy turbines have the potential to generate sufficient power for cell phones and other electronic devices. There are two types of wind turbines, horizontal and vertical axis each having their pros and cons. Vertical-axis wind turbines are the main focus of this thesis, with a reduction in their form factor or size and portable …

Team Safe Skies: Project Talon Interceptor, Cole Carlson, Peter Dinh, Sebastian Gomez, Alex Widner

Senior Design Project For Engineers

This report aims to lay out our design process for the missile interceptor aircraft. Our Talon Interceptor is an inexpensive, scaled-down, autonomous F-16 for mass production. The aircraft can ascend quickly for mission requirements while avoiding detection with its internal weapons bay. Multiple decisions have been made to ensure the initial and maintenance costs are reasonable without compromising the missions. TOPSIS reviews have been used to measure significant components unbiasedly and objectively. Our aircraft meets all the AIAA requirements while coming in under budget.

G.W.A.I.H.I.R. Guided Wing Aircraft For Intelligent Hybrid Insertion And Recovery, Abdirahman Ahmed Shirwa, Zach Richards, Derek Harwood, Alex Duncan

Senior Design Project For Engineers

The paper outlines the conceptual and preliminary design of a hybrid vertical takeoff and landing (VTOL) heavy lift unmanned aerial vehicle (UAV) for autonomous cargo transport missions. The primary design objective was to create an aircraft capable of carrying a 15 kg payload over a range of 33 km, achieving a top cruise speed of 45 km/h and maintaining an endurance capacity of at least 90 minutes.

A comprehensive literature review informed key design decision, including airfoil selection, structural material, propulsion system configuration, and control. Key requirements were established early in the design process, such as payload capacity, energy efficiency, …