Computational Engineering Commons^™

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 …

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 …

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 …

Optimization Of The Cross-Section Of Generic Flexible Bridges, Manal Kamal Zaki, Mina M. Helmy, Mark M. Tawadros

Journal of Engineering Research

This paper investigates the behavior of flexible bridges prone to aerodynamic instabilities due to wind. Optimal cross-sections that reduce aerodynamic forces are recommended. This is achieved by studying a variety of bridge sections with different widths of upper and lower sloping edges in addition to studying the upper and lower cramps of the deck. The wind velocities are also parameterized. Computations are developed based on the powerful computational fluid dynamics (CFD) method known as FLUENT and embedded in ANSYS software. For parametric study, a design of experiments (DOE) is performed based on the response surface methodology (RSM) combined with the …

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 …

The Influence Of The Reference Area Of Aileron On The N2xx Aircraft Using Computational Fluid Dynamics, Siti Nur Rahmah, Gaguk Jatisukamto, Hary Sutjahjono

Journal of Mechanical Engineering Science and Technology (JMEST)

Aileron is a control surface that functions as a regulator of roll motion. The movements of the ailerons are opposite to the left and right sides. Previous studies have shown that graphs of hinge moment coefficient (Chm) values increases with increasing angle of attack. This study is to determine the aerodynamic characteristics of aileron by combining the surface area of the vane into the aileron by varying the aileron’s deflection. The calculation is performed using a numerical method in two dimensions (2D) commercial CFD simulation software. The results of the study concluded that the hinge moment coefficient for modified airfoil …

A Cfd Study On The Performance Of High Speed Planing Hulls, Mowgli J. Crosby

Masters Theses

Most high speed water craft are able to achieve high speeds through the use of a planing hull. Planing hulls use hydrodynamic forces to lift a portion of the vessel out of the water, reducing drag, and allowing for greater speeds. Determining the flow around such vessels is traditionally achieved using a scale model in a tow tank. The purpose of this study was to analyze the performance of a high speed planing hull determine the effects of several geometric features using computational fluid dynamics rather than traditional experimentation. The goal was to determine the best configuration to ensure the …

Evaluation And Enhancement Of Clean Energy Systems: Analytical, Computational And Experimental Study Of Solar And Nuclear Cycles, Nima Fathi

Mechanical Engineering ETDs

Clean (and specifically renewable) energy is steadily improving its global share. However, finite availability of fossil fuels and the growing effects of climate change make it an urgent priority to convince the industry and governments to incentivize investment in the renewable energy field and to make it more attractive by decreasing the capital cost. Until recently, uncertainties in funding limited renewable energy development, especially in the US. That limitation has been one of the barriers to progress. Another limitation of many renewable energy systems is the variability in their output, which makes them unsuitable for baseline power production. Therefore, fossil …

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

Aviation Department Publications

No abstract provided.

Mesh Generation Using A Correspondence Distance Field, Nicholas Szapiro

Masters Theses and Doctoral Dissertations

The central tool of this work is a correspondence distance field to discrete surface points embedded within a quadtree data structure. The theory, development, and implementation of the distance field tool are described, and two main applications to two-dimensional mesh generation are presented with extension to three-dimensional capabilities in mind. First is a method for surface-oriented mesh generation from a sufficiently dense set of discrete surface points without connectivity information. Contour levels of distance from the body are specified and correspondences oriented normally to the contours are created. Regions of merging fronts inside and between objects are detected in the …

An Adaptive Hybrid Mesh Generation Method For Complex Geometries, Cameron Thomas Druyor

Masters Theses and Doctoral Dissertations

An adaptive hybrid mesh generation method is described to automatically provide spatial discretizations suitable for computational fluid dynamics or other 2D solver applications. This method employs a hierarchical grid generation technique to create a background mesh, an extrusion-type method for inserting boundary layers, and an unstructured triangulation to stitch between the boundary layers and background mesh. This method provides appropriate mesh resolution based on geometry segments from a file, and has the capability of adapting the background mesh based on a spacing field generated from solution data or some other arbitrary source. By combining multiple approaches to the grid generation …

Generation And Optimization Of Spacing Fields, Max David Collao

Masters Theses and Doctoral Dissertations

Meshes are used to discretize space for computational fluid dynamics (CFD) simulations. Mesh adaptation through refinement and smoothing can improve the accuracy of the CFD solution. In order to perform adaptive refinement or smoothing a spacing field is needed to define the desired edge sized in mesh. The objectives of this research are to generate spacing fields from existing CFD solutions and optimize this spacing information for efficient use by programs to perform adaptive refinement or smoothing. All work was done on 2D meshes with the intention of gaining knowledge and experience for later application to 3D meshes. The program …

Comparison Of Two Methods For Two Dimensional Unstructured Mesh Adaptation With Elliptic Smoothing, Matthew David O'Connell

Masters Theses and Doctoral Dissertations

A new mesh adaptation method for unstructured grids is presented. The technique uses virtual control volumes that are iteratively manipulated to conform the mesh to match either a Riemannianmetric tensor field or an equal distribution of scalar weights. Forcing functions similar to those used for structured grids are employed such that the resulting meshes can be compared with those generated using the new adaptation method. Several test cases using analytic functions to drive the mesh adaptation are also presented and compared with the new method. Mesh adaptation results driven by computed flow field information are also compared to those adapted …

Unstructured Grid Technologies For Hydrodynamic Applications With Bodies In Relative Motion And Mesh Deformation, Lei Ji

Masters Theses and Doctoral Dissertations

Unstructured grid technologies for hydrodynamic applications with bodies in relative motion and mesh deformation are presented. A parallel universal mesh deformation scheme is developed to manage deforming surface and volume grids for both aerodynamic and hydrodynamic applications. The approach is universal and independent of grid type. Also, it requires minimal inter-processor communication and is thus perfectly suitable to a parallel platform. The original scheme of Allen (2006) has difficulty deforming volume grids in regions near concave geometry features and for abrupt grid resolution changes. Several modifications are proposed to overcome these problems. Grid quality can be improved significantly by adding …

Winslow Elliptic Smoothing Equations Extended To Apply To General Regions Of An Unstructured Mesh, James Steven Masters

Masters Theses and Doctoral Dissertations

In any engineering endeavor, it is important to have the ability to efficiently and intelligently break up a region of interest in order to explore and investigate the interesting and dynamic aspects of the system enclosed in the region. In the field of fluid mechanics - and, in particular, computational fluid dynamics - this region breakup (known as discretization) has traditionally been done using structured meshes but, because of their flexibility with capturing real-world geometry, unstructured meshes are being increasingly utilized. Not surprisingly, techniques that have traditionally been reserved for structured meshes are migrating to the world of unstructured meshing …

Virtualization Of Physical Experiments Using Real-Time Data Generation From A Computational Fluid Dynamics Code, Kaustubh A. Dharwadkar

Mechanical & Aerospace Engineering Theses & Dissertations

This work presents a methodology for mapping physical experiments into real-time, web-based virtual experiments. The four broad elements included in the physical-to-virtual experiment transformation methodology are: (a) computer solution of conservation equations of mass and momentum to generate velocity and pressure (virtual) data that serve as the foundation for recreating the physical phenomenon in the virtual domain; (b) use of virtual pressure and velocity sensing devices to generate signals or readings from computed virtual data that can be observed and read on a computer screen; (c) use of visualization software such as Macromedia FLASH to create a highly interactive environment …

A Computational Method For Flow Separation Detection And Control For Axial Compressor Airfoils, Chang Jun Meang

Master's Theses - Daytona Beach

Conducting full annulus experiments on multistage compressors is costly and time consuming due to the complexity of the experimental processes. To reduce complexity, Computational Fluid Dynamics (CFD) methods are applied to turbomachinery and other applications in recent analysis of such cases. CFD methods are widely used within the aerospace industry and are increasingly demonstrating their reliability. For axial compressors, it is known that highly staggered compressor stators will increase the aerodynamic loading on the stator, which directly relates to the compressor stall and efficiency. In this work, compressor stators stagger angle is increased 4 ° to induce separation on the …