Mechanical Engineering Commons^™

Study Of Onshore And Offshore Upwind And Downwind Wind Turbine Configurations: Performance Differences And Aerodynamic Characteristics, Ahmed Ismail

Mechanical Engineering Theses

The aerodynamic performance and loading behavior of large- scale wind turbines depend heavily on atmospheric inflow conditions and rotor orientation. While upwind turbines remain the most common design in the industry, recent progress in materials, aeroelastic modeling, and control systems has sparked renewed interest in downwind configurations. This study aims to assess how ABL characteristics and rotor orientation affect the aerodynamic performance of a utility- scale wind turbine. A CFD framework was built in ANSYS Fluent to model the NREL 5 MW Reference Wind Turbine. Transient simulations employed the SST k–ε turbulence model under various inflow conditions: uniform, onshore, and …

Aquaculture Ecosystem Modeling Aeration Efficiency Optimization Using Cfd, Gabriela Reyes Gomez

Electronic Theses and Dissertations

The Harbor Branch Oceanographic Institute (HBOI) is developing the Intelligent and Resource Efficient Pond Aquaculture (IREPA) project, which aims to improve aquaculture management through the integration of predictive models and automated technologies. This approach seeks to transition traditional practices toward data-driven systems capable of supporting informed decision-making for aeration management.

This study investigates the effectiveness of different aerator configurations on hydrodynamic circulation and dissolved oxygen (DO) distribution in aquaculture ponds using computational fluid dynamics (CFD). A model was developed in ANSYS Fluent, where the aerator was represented using a power-based formulation and implemented as a moving wall boundary condition. Dissolved …

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 …

Cavitation-Aware Design Of Hydrofoil Sections For Marine Propeller Blade Development, Samuel G. Bacon

Mechanical & Aerospace Engineering Theses & Dissertations

Cavitation is a major design constraint for marine propeller blade sections because it can reduce hydrodynamic performance, increase vibration and noise, and contribute to surface damage. This thesis develops and applies an exploratory computational framework for cavitation-aware hydrofoil-section design relevant to marine propeller blade development. The framework combines section-level CFD validation, CST-based geometry parameterization, pressure-based pre-screening, matched-load comparison, and focused predicted inception envelope or cavitation-bucket analysis.

The CFD methodology was validated against published YS-920 hydrofoil water-tunnel data using selected fully wetted, near-inception, and cavitating reference cases. The validation results showed that the adopted framework reproduced the key experimental trends needed …

Patient‐Specific Computational Flow Simulation Reveals Adverse Hemodynamic Factors Associated With Occlusion Of Directional Branches After Fenestrated‐Branched Endovascular Aneurysm Repair, Kenneth Tran, Jesse Chait, Emmanuel Tenorio, Weiguang Yang, Alison Marsden, Bernardo Mendes, Jason T. Lee, Gustavo S. Oderich

Mechanical Engineering Faculty Publications

Background: Fenestrated and branched endovascular aneurysm repair can be complicated by branch vessel occlusion in the absence of structural stenosis. We hypothesized that computational flow simulation could identify adverse hemodynamic features associated with postfenestrated and branched endovascular aneurysm repair branch occlusion.

Methods: Patients undergoing 4-vessel fenestrated and branched endovascular aneurysm repair for Extent II to IV thoracoabdominal aortic aneurysms were retrospectively reviewed. Branches that occluded without identifiable kinking or stenosis on computed tomography were included, along with an equal cohort of anatomy-matched patent controls. Patient-specific pulsatile rigid-wall simulations were performed using SimVascular with individualized geometries and boundary conditions. Abnormal time-averaged …

Investigation Of Drag Force And Downforce On Two Racing Motorcycles In Slipstream Conditions, Muhamad Hanifudin, Gaguk Jatisukamto, Mahros Darsin, Muh. Nurkoyim Kustanto, Azmi Saleh, Suprihadi Prasetyono, Catur Suko Sarwono

Journal of Mechanical Engineering Science and Technology (JMEST)

The performance of modern racing motorcycles is greatly influenced by their aerodynamics. Slipstreaming occurs during a race when a rider closely follows another, especially on a straight track. The effect can reduce aerodynamic drag and increase the overall speed of the rider behind. This study investigates the aerodynamic effects of slipstreaming on a racing motorcycle using computational fluid dynamics. This study also considers its effect on both drag force and downforce, which affects motorcycle stability. A 3D CAD model of a racing motorcycle and a rider in a crouching position was used as the object of research. CFD simulations were …

Finite Volume Incompressible Lattice Boltzmann Framework For Non-Newtonian Flow Simulations In Complex Geometries, Akshay Dongre, John Ryan Murdock, Song Lin Yang

Michigan Tech Publications

Arterial diseases are a leading cause of morbidity worldwide, necessitating the development of robust simulation tools to understand their progression mechanisms. In this study, we present a finite volume solver based on the incompressible lattice Boltzmann method (iLBM) to model complex cardiovascular flows. Standard LBM suffers from compressibility errors and is constrained to uniform Cartesian meshes, limiting its applicability to realistic vascular geometries. To address these issues, we developed an incompressible LBM scheme that recovers the incompressible Navier–Stokes equations (NSEs) and integrated it into a finite volume (FV) framework to handle unstructured meshes while retaining the simplicity of the LBM …

Uncertainty Quantification Of Turbulent Premixed Flames, David L. Brown

Honors Theses

This thesis presents an uncertainty quantification (UQ) study of turbulent premixed flames, focusing on the impact of uncertainties in operating conditions on the normalized consumption speed. Namely, temperature, pressure, and equivalence ratio are the operating conditions that are under study. Due to significant computational demands associated with direct MC methods for UQ, surrogate modeling techniques including Polynomial Chaos Expansion (PCE), Stochastic Collocation (SC), and Gaussian Process (GP) are evaluated based on efficiency and accuracy. Through this study, PCE is identified as the optimal surrogate model due to its accuracy and significantly reduced computational costs. PCE is subsequently applied to investigate …

A Comparison And Investigation Of 2d Axisymmetric And 3d Models For The Wave Augmented Varicose Explosions Atomizer, Caleb Miller

Senior Honors Theses

Atomization of non-Newtonian, high-viscosity fluids is a challenging task with many applications. One method of atomizing these types of flows is the Wave Augmented Varicose Explosions (WAVE) atomizer. Using this framework, the study establishes an analysis methodology, investigates the relationship between 2D axisymmetric (2DA) and 3D models, and provides analysis of geometric, non-geometric, and non-dimensional parameter influences on the atomizer characterization in 2DA models. The study found that 2DA models can provide viable predictions of certain 3D model characteristics, established several mathematical models for parameter relationships among 2DA models, and identified certain metrics as inadequate predictors of atomizer characteristics in …

Advancing Solar Farm Resilience: Cfd-Driven Wind Load Optimization, Aly Mousaad Aly

Faculty Publications

This study investigates wind load design methods for ground-mounted solar panels and arrays by comparing Computational Fluid Dynamics (CFD) simulations with design standards. A case study of a solar farm impacted by Hurricane Maria examines the effects of elevation height, tilt angle, and variations in the American Society of Civil Engineers (ASCE) standards on wind loads and structural failure. Turbulence models, including Reynolds Stress Model, k–ε Model, and Large Eddy Simulation (LES), are used to analyze wind pressures, lift, drag, and peak pressures. Results show Phase 1 experienced higher wind loads than Phase 2 due to design differences. A cost-benefit …

Hemodynamics Of Slip Surfaces For Thrombosis Control In Implanted Cardiovascular Devices, Kieun Choi, Weiguang Yang, On Shun Pak, Jongmin Seo

Mechanical Engineering Faculty Publications

Percutaneous medical devices are preferred for the treatment of cardiovascular diseases due to their minimal intervention compared to surgery. However, complications such as thrombosis remain significant challenges. This study aims to investigate the hemodynamic effects of slip surfaces on pacemaker leads and coronary stents using computational fluid dynamics under physiological conditions. Two computational models were developed: a venous anatomical model with a pacemaker lead and a coronary artery model with a stent. Slip boundary conditions were applied to these devices, and we quantitatively analyzed critical hemodynamic parameters, including wall shear stress (WSS) and residence time (RT), which are associated with …

Identifying The Effect Of Architecture Morphology On Wind Fields And Pm2.5 Dispersion At The Urban Block Scale Via A Combined Scheme, Bin Guo, Lu Li, Xiaowei Zhu, Zheng Wang, Miaoyi Chen, Lin Pei, Tengyue Guo

Mechanical and Materials Engineering Faculty Publications and Presentations

This study explores the potential of architecture morphology to mitigate PM2.5 pollution through enhanced urban ventilation. Despite the recognized influence of building designs on wind and air pollution distribution at the urban block scale, specific mechanisms remain poorly understood. To address this gap, we have developed an integrative approach combining in-situ observations, Geographic Information System (GIS), Remote Sensing (RS), Computational Fluid Dynamics (CFD), and statistical modeling. Here, CFD simulates the flow field and PM2.5 dispersion, using in-situ observations for turbulence model selection. GIS quantify architecture morphology parameters to establish accurate CFD boundary conditions, ensuring simulations reflect real-world conditions and precise …

Numerical Investigation Of Pressurized Oxy-Combustion, Lei Li

Graduate Theses, Dissertations, and Problem Reports (ETD)

Pressurized oxy-combustion (POC) is emerging as a promising and transformative technology for carbon capture, utilization, and storage, offering advantages of low cost, low emissions, and high efficiency. POC operates by burning pulverized coal at elevated pressures in a recycled flue gas environment, typically rich in O₂ and CO₂. This study presents a comprehensive numerical investigation into the fundamental behaviors of lab-scale POC reactors, using both two-dimensional (2D) Reynolds-Averaged Navier-Stokes (RANS) simulations and three-dimensional (3D) Large-Eddy Simulations (LES) with the commercial computational fluidized dynamics (CFD) software package ANSYS Fluent.

The primary focus of this work is to understand flame stabilization and …

Multiphysics Modeling And Experimental Validation Of High-Strength Steel In Laser Powder Bed Fusion Process, M. Rangapuram, S. Babalola, J. W. Newkirk, L. N. Bartlett, F. W. Liou, K. Chandrashekhara, Stephen R. Cluff

Materials Science and Engineering Faculty Research & Creative Works

Laser powder bed fusion (LPBF) is a subset of the additive manufacturing process in which a laser beam selectively joins the metal powder into a desired part in a sequential layer process. Owing to its complex nature of rapid heating and cooling of the melt pool, there is a need to understand the melt pool behavior and its effects on the final manufactured part. a densely packed powder bed is highly desirable for fabricating a superior part using the LPBF process. in this work, discrete element model was used to generate powder beds with realistic powder properties and various factors …

Sediment Transport On Rippled Beds, Octavio Guevara, L. Guan, J. S. Salinas, ‪Nadim Zgheib, S. Balachandar

Mechanical Engineering Faculty Publications

We conduct an Euler-Lagrange, direct numerical simulation of a turbulent channel flow at a shear Reynolds number of Reτ=180 over an erodible particle bed. The particle bed consists of approximately 1.3 × 10⁶ monodisperse particles, resulting in a bed thickness of around 12–13 particles. The particle density and size are chosen to achieve a ratio of 4 for the Shields stress to the critical Shields stress necessary for incipient motion such that particle transport occurs primarily as bedload. The simulation is run long enough for ripples to form. We track the temporal evolution of the particle flux and excess …

Multiphysics Simulation Of Biochar Adsorption Rates, Joseph Salerno

Graduate Theses & Non-Theses

An accepted carbon capture and sequestration (CCS) method to remove carbon dioxide from the atmosphere is via adsorption onto biochar. While the characteristics of the char are important and greatly impact the adsorption of CO2 molecules, the conditions in which the adsorption occurs are equally critical. Factors such as char particle size and quantity, environmental temperature and pressure, as well as outside driving mechanisms such as vibration frequency, driving force, and flow rates play an impactful role on how the char adsorbs CO2 particles. These factors and their effects will be studied in multiphysics simulations performed using methods that work …

Investigation On The Effects Of Biofouling On The Boundary Layer, Adam N. Bacon

LSU New Orleans Theses and Dissertations

This study is an investigation of the effect of biofouling on the boundary layer of a flat plate and a NACA 4-digit series foil. Three identical hydrofoils made of resin were placed in the Gulf of Mexico at Grand Isle, Louisiana, and observed and analyzed by marine biologists at the University of New Orleans for their species composition. The resulting biofouling that grew was primarily made up of barnacles and bryozoans. The foils were submerged in an open channel flume at zero incidence and subjected to a series of experiments whose arc-length Reynolds numbers ranged from approximately 13000 to 32000. …

Experimental And Numerical Investigation Of Air-Cooled Heat Sinks, Ethan Weems

Mechanical Engineering Undergraduate Honors Theses

Lightweight and affordable cooling capabilities are critical as the physical scale of electronics continues to decrease. Air-cooled heat sinks that dissipate heat from electronic components to the surrounding air are excellent candidates to fill this role. While plate-fin and pin-fin heat sinks have been implemented extensively for electronic cooling, recent advances in additive manufacturing enable the fabrication of more complex structures. In this undergraduate Honors thesis, a means by which to generate novel heat sink geometries is presented. To that end, an experimental characterization facility is developed to evaluate existing traditional heat sinks. The heat transfer performance of the heat …

Developing General Purpose Apps To Automate Image Analysis Of Wave-Augmented-Varicose-Explosion Atomization And Other Multi-Phase Interfacial Flows, Ethan Newkirk

Senior Honors Theses

Atomization involves disrupting a flow of contiguous liquid into small droplets ranging from one submicron to several hundred microns (micrometers) in diameter through the processes of exerting sufficient forces that disrupt the retaining surface tensions of the liquid. Understanding this phenomenon requires high-speed imaging from physical models or rigorous multiphase computational fluid dynamics models. We produce a MATLAB application that utilizes various methods of image analysis to quickly analyze and store mathematical data from detailed image analyses. We present a user with numerous tools and capabilities that provide results that deviate from 1.8% to 8.9% of the original image sequence …

Performance Effects Of Dissociated Hydrogen In Nuclear Thermal Propulsion Engines, Richard Adam Gorrell

UNLV Theses, Dissertations, Professional Papers, and Capstones

Nuclear thermal propulsion (NTP) research considers hydrogen dissociation as negligible to design and analysis of propulsion engines. This study reintroduces chemically reacting flow to NTP engine analysis for investigation of the dissociation effect on engine performance. A first-principles approach observes the basic chemical mechanism and reaction within the high-speed, high-temperature NTP flow to baseline expected atomic hydrogen levels and validate equilibrium. A surface reaction study looks into hydrogen absorption through dissociation and its effect on the boundary layer, and bulk flow. For total performance, the resulting dissociated flow is analyzed through nozzle expansion and performance metrics calculated.

All historic reactor …

Aerodynamic Design And Analysis Of A Modified 2006 Mazda Miata, William N. Recher

Honors College Theses

Aerodynamic forces developed by automobiles have destabilizing effects at high speed. These forces tend to skew toward a vehicle’s rear which can present safety concerns, especially for rear-wheel-drive automobiles like the Mazda Miata. To address oversteer and high-speed instability, a vehicle’s design can be tailored to bring about aerodynamic balance and improve traction. LiDAR was used to bring the physical automobile into the digital space. Then, a splitter and diffuser were added to reduce the magnitude of the destabilizing forces. Next, the size and shape of the rear-wing required to balance the vehicle was calculated using a combination of parameters …

Numerical Simulation And Optimization Of Fin Configurations For Enhanced Heat Sink Performance In Aluminum And Copper Materials, Rimpy Singh

Mechanical and Aerospace Engineering Theses - Archive

The constant evolution of data centers and high-power electronic systems has raised critical challenges in heat dissipation and thermal management. Single-phase immersion cooling, where electronic components are submerged in a thermally conductive but non-electrically conductive liquid (dielectric liquid), offers improved heat dissipation capabilities and emerges as a promising alternative to traditional air-cooling methods, which often fail to meet the thermal demands of densely packed, high-power systems. This study investigates and compares the thermal performance of aluminum and copper heat sinks with fin thicknesses of 0.33 mm and 0.54 mm, respectively, using finite element analysis based on computational fluid dynamics (CFD) …

Rans-Dns Simulations For Uncertainty Quantification In Dns Data Of Turbulent Mixing Layer, Mohamed Abuhegazy

Mechanical Engineering ETDs

Mixing layer flow is one of the canonical free shear flows in fluid dynamics. Such a flow is formed when two fluid streams move along one another with different velocities. Investigation of this flow development has been an active topic of research for many decades not only due to a wide range of environmental and technological applications where this flow may be observed, but also because of large discrepancies in the results obtained experimentally and numerically regardless this flow simple geometry. In this dissertation, the quality and uncertainty of extracted turbulent statistics of mixing layer flow are analyzed by applying …

Heat And Mass Transfer Modeling Of High-Temperature Moving-Bed Thermochemical Reactors, David Korba

Theses and Dissertations

With the global deployment of renewable energy generation at record rates, clean energy is steadily becoming competitive with its fossil-fuel counterparts. However, further expansion is limited by the inherent intermittency of renewable energy sources (solar, wind, wave, etc.), which typically do not match with daily and seasonal variations of global (and local) energy demand. Thermochemical energy storage (TCES) has demonstrated strong potential in being a technological pathway to provide on-demand process heat and handle the intrinsic variations in renewable energy generation and energy demand. TCES works on the premise of excess renewable heat driving an endothermic reduction reaction, in which …

Carbon/Carbon Composites For Next Generation Microvascular Solar Thermal Receivers, Matt Zuzelski

Boise State University Theses and Dissertations

Concentrating solar power (CSP) is a method of renewable solar power generation where the sun’s radiant energy is collected by a receiver and converted into thermal energy. This thermal energy is then passed into a heat transfer fluid and either sent to thermal storage, or a steam power plant. One path to better CSP systems is improving the operational envelope of the receiver and heat transfer fluid (HTF) system by utilizing more resilient absorbing materials, different path architectures, and HTFs with higher allowable temperatures.

A new carbon/carbon composite is being developed with the potential to function as the absorbing material …

Considering The Influence Of Coronary Motion On Artery‑Specific Biomechanics Using Fluid–Structure Interaction Simulation, Nicholas A. T. Fogell, Miten Patel, Pan Yang, Roosje M. Ruis, David B. Garcia, Jarka Naser, Fotios Savvopoulos, Clint Davies Taylor, Anouk L. Post, Ryan M. Pedrigi, Ranil De Silva, Rob Krams

Department of Mechanical and Materials Engineering: Faculty Publications

The endothelium in the coronary arteries is subject to wall shear stress and vessel wall strain, which influences the biology of the arterial wall. This study presents vessel-specific fluid–structure interaction (FSI) models of three coronary arteries, using directly measured experimental geometries and boundary conditions. FSI models are used to provide a more physiologically complete representation of vessel biomechanics, and have been extended to include coronary bending to investigate its effect on shear and strain. FSI both without- and with-bending resulted in significant changes in all computed shear stress metrics compared to CFD (p = 0.0001). Inclusion of bending within …

Neural Network Flow Optimization Using An Oscillating Cylinder, Meihua Zhang, Zhongquan Charlie Zheng, Yangliu Liu, Xiaoyu Jiang

Mechanical and Aerospace Engineering Student Publications and Presentations

Flow behaviors of a downstream object can be affected significantly by an upstream object in close proximity. Combined with the neural network algorithms, this concept is used for flow control in this study to optimize the aerodynamic performance of a downstream object. Flow with an oscillating cylinder placed upstream is systematically studied because there are multiple control parameters that influence the flow dynamics around the downstream object. These control parameters are used as the input factors of a back-propagation neural network, and then a revised genetic algorithm is applied to find the optimal set of control parameters. In the current …

Jet Noise Reduction: A Fresh Start, Christopher K. Tam, Fang Q. Hu

Mathematics & Statistics Faculty Publications

Attempts to reduce jet noise began some 70 years ago. In the literature, there have been many publications written on this topic. By now, it is common knowledge that jet noise consists of a number of components. They possess different spectral and radiation characteristics and are generated by different mechanisms. It appears then that one may aim at the suppression of the noise of a single component instead of trying to reduce jet noise overall. The objective of the present project is to reduce large turbulence structures noise. It is the most dominant noise component radiating in the downstream direction. …

Effects Of Direct Water Injection On The Nitrogen Oxide Emission Characteristics Of Marine Diesel Engines, Mahmoud Abdelnaser Saadeldin, M. M. Elgoharya, Maged Abdelnaby, Mohamed R. Shouman

Journal of Marine Science and Technology–Taiwan

This study examines the issue of diesel emissions from vehicles and vessels and their impact on environmental degradation with a focus on nitrogen oxide (NOx) emissions and their contribution to air pollution-related deaths worldwide. The novelty of this work is the use of computational fluid dynamics simulations to investigate the effectiveness of water addition for reducing NOx emissions. This study considers two methods of water addition, i.e., injection of water and air into a combustion chamber and mixing of water with fuel before injection. Adding water to air systems at 10% and 20% ratios reduces NOx emissions by 5% and …

Development Of Alternative Air Filtration Materials And Methods Of Analysis, Ivan Philip Beckman

Theses and Dissertations

Clean air is a global health concern. Each year more than seven million people across the globe perish from breathing poor quality air. Development of high efficiency particulate air (HEPA) filters demonstrate an effort to mitigate dangerous aerosol hazards at the point of production. The nuclear power industry installs HEPA filters as a final line of containment of hazardous particles. Advancement air filtration technology is paramount to achieving global clean air. An exploration of analytical, experimental, computational, and machine learning models is presented in this dissertation to advance the science of air filtration technology. This dissertation studies, develops, and analyzes …