Computational Engineering Commons^™

Experimental-Motion-Driven Cfd Investigation Of Slosh Dynamics In Propellant Tanks Of Spacecraft And Launch Vehicles, Priyanshu Savaliya

Doctoral Dissertations and Master's Theses

Liquid sloshing in partially filled propellant tanks can generate transient forces and moments that affect spacecraft and launch vehicle stability, guidance, and control. This research develops a one-way experimental-to-Computational Fluid Dynamics (CFD) integration framework to investigate free-surface slosh behavior under realistic excitation conditions.

The overarching goal of this thesis is to develop and evaluate a one-way experimental-motion-driven computational framework for predicting liquid slosh response in a partially filled cylindrical tank. Rather than relying on idealized sinusoidal inputs, this work uses experimentally measured actuator-feedback motion as the prescribed excitation for high-fidelity CFD. The central objective is to establish the experimental and …

Numerical Study Of Nutrient Mixing In Trabecular Bone In Microgravity, Disuse And Normogravity, Sagar Gharti

Doctoral Dissertations and Master's Theses

Mechanical loading is known to regulate bone remodeling by driving interstitial fluid flow which stimulates cells and drives nutrient transport within the trabecular network. In microgravity, the absence of mechanical stimulation or loading suppresses convective flow processes, causing diffusion-driven nutrient mixing and renewal, and accelerated bone loss. This thesis investigates how oscillation frequency and trabecular bone density jointly control nutrient mixing and wall shear stress within trabecular cavities.

A computational fluid dynamics (CFD) framework is developed in STAR-CCM+ using a soft-cap oscillation model that mimics cyclic compression. Three idealized trabecular morphologies are simulated across different frequencies to represent microgravity or …

Exploration Of Physics-Informed Grid Generation Technique For Wall-Modeled Les Using Eagle3d, Dominic Schneider

Doctoral Dissertations and Master's Theses

Wall-Modeled Large Eddy Simulation (WMLES) is an area of interest due to its ability to lower computational costs of LES. Even with the application of wall models, LES still proves to have practicality issues when it comes to use in industry, due to the expertise, time, and computational resources required. A novel technique for generating a lean, physics based WMLES grid is described.

The technique utilizes a RANS solution to extract turbulence information, user-specified values related to resolution of turbulent energy levels, acoustics waves, and shock waves, to generate a point cloud for producing a lean WMLES grid with in-house …

Assessing The Impact Of Femur Morphological Variations On Pediatric Hip Joint Biomechanics Using Statistical Shape Modeling, Tamara Chambers

Doctoral Dissertations and Master's Theses

This dissertation aimed to (1) quantify morphological variations in the pediatric hip joint and (2) evaluate the sensitivity of an infant musculoskeletal model (MSM) to these variations, considering hip joint center estimation errors. A shape statistical model (SSM) of decedent infant femurs from the Ortolani collection was created using ShapeWorks, capturing key morphological features, such as variations in the femoral neck-shaft and anteversion angles. Seven synthetic femurs were generated from the SSM to create SSM-informed MSMs, which were systematically evaluated through kinematics and kinetics analyses in OpenSim. Incorporating the SSM led to slight changes in the pediatric MSMs’ kinematics but …

Development Of On-The-Fly Quasi-Steady State Approximation For Chemical Kinetics In Cfd, Abhinav Balamurugan

Doctoral Dissertations and Master's Theses

This study analyzes the feasibility of On-The-Fly Quasi-Steady-State Approximation (OTF-QSSA) application for solving chemical kinetics within Computational Fluid Dynamics (CFD) simulations, aiming to reduce the computational demand of detailed mechanisms. An algorithm that dynamically identifies and designates Quasi-Steady-State (QSS) species at specific grid locations and instances during the simulation was developed. With this information, our method pseudo-delays the advancement of concentrations for these QSS species—effectively setting their rate of concentration change to zero for a set number iteration before updating using the detailed mechanism and thereby omitting the computationally intensive processes typically required for their calculation during those skipped iteration. …

Deep Cnn-Based Automated Optical Inspection For Aerospace Components, Shashi Bhushan Jha

Doctoral Dissertations and Master's Theses

ABSTRACT

The defect detection problem is of outmost importance in high-tech industries such as aerospace manufacturing and is widely employed using automated industrial quality control systems. In the aerospace manufacturing industry, composite materials are extensively applied as structural components in civilian and military aircraft. To ensure the quality of the product and high reliability, manual inspection and traditional automatic optical inspection have been employed to identify the defects throughout production and maintenance. These inspection techniques have several limitations such as tedious, time- consuming, inconsistent, subjective, labor intensive, expensive, etc. To make the operation effective and efficient, modern automated optical inspection …

Resilience Model For Teams Of Autonomous Unmanned Aerial Vehicles (Uav) Executing Surveillance Missions, Robert Koeneke

Doctoral Dissertations and Master's Theses

Teams of low-cost Unmanned Aerial Vehicles (UAVs) have gained acceptance as an alternative for cooperatively searching and surveilling terrains. These UAVs are assembled with low-reliability components, so unit failures are possible. Losing UAVs to failures decreases the team's coverage efficiency and impacts communication, given that UAVs are also communication nodes. Such is the case of a Flying Ad Hoc Network (FANET), where the failure of a communication node may isolate segments of the network covering several nodes. The main goal of this study is to develop a resilience model that would allow us to analyze the effects of individual UAV …

Extracting A Body Of Knowledge As A First Step Towards Defining A United Software Engineering Curriculum Guideline, Anton Kiselev

Doctoral Dissertations and Master's Theses

In general, the computing field is a rapidly changing environment, and as such, software engineering education must be able to adjust quickly to new needs. Industry adapts to technologies as fast as it can, but the critical issue is a need for recent graduates with the necessary expertise and knowledge of new trends, technologies, and practical experience. The industries that employ graduates of computing degree programs aim to hire those who are familiar with the latest technical traits, tools, and methodologies to meet these needs, and the software engineering curriculum needs to respond quickly to these needs. Still, unfortunately, software …

Numerical Simulation Of A Cryogenic Spray, Neel Kishorkumar Shah

Doctoral Dissertations and Master's Theses

Cryogenic sprays have many applications in modern engineering. Cooling of electronic equipment subject to high heat flows, surgical ablation of gastrointestinal mucosae or orbital maneuvering are a few examples of their versatility. However, the atomization of a cryogenic liquid is a complex process. During such an event, aerodynamic effects associated with secondary atomization are further affected by thermodynamic flashing. A better understanding of the characteristics of cryogenic sprays is then necessary to allow for improved design and optimization in applications. The overarching objective of this study is to document such characteristics. The numerical simulation was performed over cryogenic nitrogen spray …

Coupled Fluid-Structure Interaction Modeling Of A Parafoil, Brandon Burnett

Doctoral Dissertations and Master's Theses

In the summer of 2014, Performance Designs, Inc. contacted Embry-Riddle Aeronautical University’s Eagle Flight Research Center to lead an investigation on square parachute design and optimization using modern computational methods to reduce costs in experimental testing. This thesis investigates the foundation for using an implicit fluid-structure interaction computational model to tackle the challenges of modeling a highly-flexible, porous fabric for design optimization of a parafoil parachute’s transient performance. Canopy deformations of a single-cell square parafoil using a fluid-structure interaction (FSI) model with nonlinear material modeling is compared to an experimental setup of matching geometry. The results of this thesis yielded …

Separation Bubbles And Vortex Formation In Cavity Flows, Kartheek Ravulapati

Doctoral Dissertations and Master's Theses

This research is a computational fluid dynamic study of the formation of vortices and separation bubbles in a square cavity as well as in a cylindrical cavity. Whereas there has been previous research work on the problem of a free stream over different types of cavities, like open and closed cavities or lid driven cavities, this research on an inlet induced flow inside a square cavity lead to unusual and interesting basic fluid dynamical phenomena. The flow in a square cavity and in a cylindrical cavity is simulated over a range of Reynolds numbers and the appearance of separation bubbles …

Computing Radiation Exchange, Jonathan L. Nutzati Fontaine

Doctoral Dissertations and Master's Theses

A computational tool to simulate thermal radiation between surfaces is developed. The output is verified against cases for which the analytical solutions are available. The tool can be used as a stand-alone program, or as an interactive module for CFD. In such an application the module would augment other heat transfer boundary conditions. The tool is demonstrated by post-processing surface temperature field data from a supersonic CFD calculation. The result is a net thermal radiation surface data field - the black body radiative effluxes as functions of temperature, less the integrated influxes multiplied by their geometric view factors from other …