Aerodynamics and Fluid Mechanics Commons^™

Modeling Of Supersonic Wave And Shock Propagation Using The Lattice Boltzmann Method, Timothy P. Schroeder

Beyond: Undergraduate Research Journal

The lattice Boltzmann method (LBM) has emerged as a mesoscopic alternative to traditional Navier-Stokes solvers for modeling fluid dynamics offering advantages in computational efficiency, parallelization, and handling of complex boundaries. Despite these strengths, accurately reproducing compressible, shock-driven phenomena remains challenging. This study investigates the performance of LBM in simulating the Sod shock tube problem, a classical benchmark for compressible flow-using both single and double distribution function formulations across one- and two-dimensional lattice stencils. A MATLAB-based solver was developed to model the flow under isothermal conditions and compared to the analytical solution using the L2 norm error. The one-dimensional models achieved …

Extending The Essentially Entropic Lattice Boltzmann Method To Three-Dimensional Turbulent Flows, Michael Derderian

Discovery Day - Daytona Beach

The Entropic Lattice Boltzmann Method (EELBM) has demonstrated strong numerical stability and accuracy for two-dimensional simulations, particularly at higher resolutions where the entropic formulation introduces only minimal stabilizing turbulent viscosity and eventually converges to the Lattice Bhatnagar–Gross–Krook (LBGK) formulation. This built-in stabilization can be interpreted as an implicit large-eddy simulation (LES) model, allowing EELBM to capture complex turbulent behavior without requiring explicit subgrid-scale closures. While these advantages have been thoroughly validated in 2D, understanding how the entropic constraint regulates dissipation in three dimensions is essential for assessing EELBM’s suitability for practical, turbulence-dominated applications. This work focuses on the development and …

Application Of Navier Stokes In Cfd, Hayden Kerkhoff, Gavin Palmer, Garret Seckinger

Discovery Day - Daytona Beach

This project investigates the use of 2-Dimensional Computational Fluid Dynamics (CFD) to analyze aerodynamic behavior, then compare data with the numerical solution of the Navier–Stokes equations run by MATLAB. By leveraging open‑source and possible industry CFD platforms—including OpenFOAM and commercial solvers such as ANSYS Fluent and Inventor Professional—the study evaluates how computational methods simulate, optimize, and predict key aerodynamic quantities such as lift, drag, stall angle, and Reynolds number.   The project focuses on modeling an airflow over specific parameters, such as different angles of attacks and ISA Atmospheric Conditions. Parametric variations in density, angle of attack, chord length, and temperature …

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 …

Turbulent Plenum Jet-Crossflow Validation Via Subgrid Scale Model Variation And Upstream Forcing Under Dynamic Hybrid Rans-Les, Cole W. Mccallum

Mechanical Engineering Undergraduate Honors Theses

In modern gas turbine design, film cooling has become ubiquitous as a method for limiting heat transfer between high temperature gases post-combustion and the surface of downstream blades. This paper validates the use of various computational fluid dynamics techniques in recreating an experiment measuring adiabatic effectiveness over a surface downstream of a compound-angle N2 plenum jet incident on a turbulent-air boundary layer [1]. To do this, both RANS and Dynamic Hybrid RANS-LES (DHRL) methods are implemented and compared to previous research [2]. The latter method is then modified through implementation of a different subgrid scale (SGS) model and through addition …

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 …

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 …

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 …

Enhancing Gas Cyclone Performance With Exit Diffusers, Omar Mohamed Mourad Dwidar, Yasser El-Shaer, Khairy Elsayed, Seyyed Hossein Hosseini, Goodarz Ahmadi

Journal of Engineering Research

This study evaluates seven cyclone designs to enhance pressure drop and collection efficiency (CE), using the conventional cyclone as a baseline. While the conventional design is efficient in particle collection, it experiences significant energy losses due to high values of pressure drops. This study introduces exit diffusers with various configurations—A, B, C, D, E, and F—to improve cyclone performance. Computational Fluid Dynamics (CFD) simulations were used to analyse the pressure drop, tangential velocity, and static pressure at different levels of each cyclone. The findings reveal that cyclone D achieves a 41.1% reduction in pressure drop but at the cost …

Direct Numerical Simulation Of Pulsating Flow In Curved Pipes: Insights Into Aortic Dissection In Humans, Gokul Anugrah Gopakumar

Theses and Dissertations--Mechanical and Aerospace Engineering

This dissertation investigates the hemodynamics of pulsating blood flow in curved vessels through direct numerical simulations (DNS), with the overarching aim of uncovering fluid dynamic mechanisms linked to the onset and progression of aortic dissection in humans. The work is structured in two parts: (i) fundamental studies in idealized geometries and (ii) preliminary investigations in patient-specific anatomies. In the first part, curved pipe models representing the aortic arch are used to isolate the effects of pulsation frequency, amplitude ratio, and curvature ratio on transitional and turbulent flow dynamics. The simulations reveal that curvature-driven centrifugal forces shift the peak velocity toward …

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 …

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. …

Two-Phase Flow Simulations With Plic-Vof Method And Dynamic Mesh Refinement, Vimalan Adaikalanathan

Mechanical and Aerospace Engineering Dissertations - Archive

Two-phase flows are critical in a variety of engineering applications that span multiple length scales. These applications encompass macroscopic phenomena, such as dam breakage and wave-structure interactions, as well as microscopic events, including droplet impacts and boiling, and mixed-scale issues like spray dynamics. Accurate representation of evolving interfaces is essential for numerical simulations of these problems, and the Volume of Fluid (VOF) method combined with the Piecewise Linear Interface Calculation (PLIC) approach is employed to fulfill this requirement. To tackle the computational challenges associated with high-resolution meshes in deforming two-phase flows, Adaptive Mesh Refinement (AMR) is utilized to enhance mesh …

Steady And Transient Study Of Conjugate Heat Transfer In Regenerative Cooled Nozzle, Khaled Bensayah, Khadidja Kamri

Emirates Journal for Engineering Research

The Heat transfer is one of the most serious challenges that exist in a supersonic nozzle flow. The combustion chamber wall and the nozzle are exposed to high-temperature gases during combustion and gas expansion, which can eventually lead to structural failure. This paper reports a computational study of steady and transient conjugate heat transfer in regenerative water cooled nozzle. Numerical computation solved Reynolds-averaged equations based on RSM-Omega turbulence model coupling with solid-phase heat conduction equation and with coolant-phase. The effect of four inlet cooled approach length 0 inch, 6 inch, 12 inch and 18 inch are studied and validated against …

Impact Of Spallation And Internal Radiation On Fibrous Ablative Materials, Raghava Sai Chaitanya Davuluri

Theses and Dissertations--Mechanical and Aerospace Engineering

Space vehicles are equipped with Thermal Protection Systems (TPS) that encounter high heat rates and protect the payload while entering a planetary atmosphere. For most missions that interest NASA, ablative materials are used as TPS. These materials undergo several mass and energy transfer mechanisms to absorb intense heat. The size and construction of the TPS are based on the composition of the planetary atmosphere and the impact of various ablative mechanisms on the flow field and the material. Therefore, it is essential to quantify the rates of different ablative phenomena to model TPS accurately. In this work, the impact of …

Design And Development Of Active Flow Effectors, Konstantinos Kanistras

Summer Community of Scholars (RCEU and HCR) Project Proposals

No abstract provided.

Design And Development Of An Online Wind Tunnel, Konstantinos Kanistras

Summer Community of Scholars (RCEU and HCR) Project Proposals

No abstract provided.

Numerical And Scaling Study On Application Of Inkjet Technology To Automotive Coating, Masoud Arabghahestani Dr.

Theses and Dissertations--Mechanical and Aerospace Engineering

A thorough literature review identified lack of precision control over quality of droplets generated by the currently available industrial sprayers and a growing need for higher quality droplets in the coating industry. Particularly, lack of knowledge and understanding in continuous inkjets (CIJ) and drop-on-demand (DOD) technologies is identified as significant. Motivated by these needs, this dissertation is dedicated to computational fluid dynamics (CFD) and scaling studies to improve existing inkjet technologies and develop new designs of efficient coating with single and/or multiple piezoelectric sensors to produce on-demand droplets. This dissertation study aims at developing a new DOD type coating technology, …

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 …

Fluid-Structure Interaction Of Nrel 5-Mw Wind Turbine, Mohamed Sayed Elkady Abd-Elhay

Theses and Dissertations

Wind energy is considered one of the major sources of renewable energy. Nowadays, wind turbine blades could exceed 100 m to maximize the generated power and minimize produced energy cost. Due to the enormous size of the wind turbines, the blades are subjected to failure by aerodynamics loads or instability issues. Also, the gravitational and centrifugal loads affect the wind turbine design because of the huge mass of the blades. Accordingly, wind turbine simulation became efficient in blade design to reduce the cost of its manufacturing. The fluid-structure interaction (FSI) is considered an effective way to study the turbine's behavior …

The Development And Validation Of Sinatra: A Three-Dimensional Direct Simulation Monte Carlo (Dsmc) Code Written In Object-Oriented C++ And Performed On Cartesian Grids, David Matthew Galvez

Master's Theses

The field of Computational Fluid Dynamics (CFD) primarily involves the approximation of the Navier-Stokes equations. However, these equations are only valid when the flow is considered continuous such that molecular interactions are abundant and predictable. The Knudsen number, $Kn$, which is defined as the ratio of the flow's mean free path, $\lambda$, to some characteristic length, $L$, quantifies the continuity of any flow, and when this parameter is large enough, alternative methods must be employed to simulate gases. The Direct Simulation Monte Carlo (DSMC) method is one which simulates rarefied gas flows by directly simulating the particles that compose the …

Multiphase Flow Modeling For Design And Optimization Of A Novel Down-Flow Bubble Column, Mutharasu Lalitha Chockalingam

LSU Doctoral Dissertations

The application of the Euler-Euler framework based Computational Fluid Dynamics (CFD) models for simulating the two-phase gas-liquid bubbly flow in down-flow bubble columns is discussed in detail. Emphasis is given towards the modelling and design optimization of a novel down-flow bubble column. The design features of this novel down-flow bubble column and its advantages over a conventional Plunging Jet down-flow bubble column are discussed briefly. Then, some of the present challenges in simulating a conventional Plunging Jet down-flow bubble column in the Euler-Euler framework is highlighted, and a sigmoid function based drag modification function is implemented to overcome those challenges. …

Uncertainty Quantification Of Turbulence Model Closure Coefficients On Openfoam And Fluent For Mildly Separated Flows, Ike Witte

McKelvey School of Engineering Graduate Student Theses & Dissertations

In this thesis, detailed uncertainty quantification studies focusing on the closure coefficients of eddy-viscosity turbulence models for several flows using two CFD solvers have been performed. Three eddy viscosity turbulence models considered are: the one-equation Spalart-Allmaras (SA) model, the two-equation Shear Stress Transport (SST) k-ω model, and the one-equation Wray-Agarwal (WA) model. OpenFOAM and ANSYS Fluent are used as flow solvers. Uncertainty quantification analyses are performed for subsonic flow over a flat plate, subsonic flow over a backward-facing step, and transonic flow past an axisymmetric bump. In the case of flat plate, coefficients of pressure, lift, drag, and skin friction …

Computational Fluid Dynamics Is Key To Better Flying Aircraft, Nihad E. Daidzic

Aviation Department Publications

No abstract provided.

On The Selection Of A Good Shape Parameter For Rbf Approximation And Its Application For Solving Pdes, Lei-Hsin Kuo

Dissertations

Meshless methods utilizing Radial Basis Functions~(RBFs) are a numerical method that require no mesh connections within the computational domain. They are useful for solving numerous real-world engineering problems. Over the past decades, after the 1970s, several RBFs have been developed and successfully applied to recover unknown functions and to solve Partial Differential Equations (PDEs).
However, some RBFs, such as Multiquadratic (MQ), Gaussian (GA), and Matern functions, contain a free variable, the shape parameter, c. Because c exerts a strong influence on the accuracy of numerical solutions, much effort has been devoted to developing methods for determining shape parameters which provide …

Computational Fluid Dynamics Study Of Balloon System Tethered To A Stratosail, Jayakanth Loganathan, Kian-Meng Lim, Heow Pueh Lee, Boo Cheong Khoo

2017 Academic High Altitude Conference

In this paper, we present a numerical study of a stratospheric balloon system tethered to a passive device, known as the Stratosail, for station-keeping operation. For scientific applications, stratospheric balloons that operate at altitudes between 15 and 20 km will need to maintain station over a fixed point above the earth for a prescribed period of time. This is a challenging problem due to the limitation of payloads and lack of an energy source. The present study uses computational fluid dynamics (CFD) simulations to analyze the drift velocity of such a balloon-Stratosail system under typical wind conditions in the stratosphere. …

Modeling Of Spallation Phenomenon In An Arc-Jet Environment, Raghava Sai Chaitanya Davuluri

Theses and Dissertations--Mechanical and Aerospace Engineering

Space vehicles, while entering the planetary atmosphere, experience high loads of heat. Ablative materials are commonly used for a thermal protection system, which undergo mass removal mechanisms to counter the heat rates. Spallation is one of the ablative processes, which is characterized by the ejection of solid particles from the material into the flow. Numerical codes that are used in designing the heat shields ignore this phenomenon. Hence, to evaluate the effectiveness of spallation phenomenon, a numerical model is developed to compute the dynamics and chemistry of the particles. The code is one-way coupled to a CFD code that models …

Inkjet Printing: Facing Challenges And Its New Applications In Coating Industry, Sadegh Poozesh

Theses and Dissertations--Mechanical and Aerospace Engineering

This study is devoted to some of the most important issues for advancing inkjet printing for possible application in the coating industry with a focus on piezoelectric droplet on demand (DOD) inkjet technology. Current problems, as embodied in liquid filament breakup along with satellite droplet formation and reduction in droplet sizes, are discussed and then potential solutions identified. For satellite droplets, it is shown that liquid filament break-up behavior can be predicted by using a combination of two pi-numbers, including the Weber number, We and the Ohnesorge number, Oh, or the Reynolds number, Re, and the Weber number, …

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 …

Experimental Investigation Of Mist Film Cooling And Feasibility Study Of Mist Transport In Gas Turbines, Reda M. Ragab

LSU New Orleans Theses and Dissertations

In the modern advanced gas turbines, the turbine inlet temperature may exceed 1500°C as a requirement to increase power output and thermal efficiency. Therefore, it is imperative that the blades and vanes are cooled so they can withstand these extreme temperatures. Film cooling is a cooling technique widely used in high-performance gas turbines. However, the film cooling effectiveness has almost reached plateau, resulting in a bottleneck for continuous improvement of gas turbines' efficiency.

In this study, an innovative cooling scheme, mist film cooling is investigated through experiments. A small amount of tiny water droplets with an average diameter about 10-15 …