Engineering Commons^™

Effect Of Surface Fluid Entrapment In A Laminar Flat Plate Boundary Layer, Abigail Hays

Mechanical Engineering Research Theses and Dissertations

For streamlined objects in laminar flow, the drag is dominated by friction drag. To counteract this, the boundary condition of the object can be changed to introduce an apparent slip on the surface. A number of approaches have been proposed for introducing surface slip to reduce drag and viscous resistance in fluid flows. This work investigates a novel approach to providing slip via fluid entrapment in a perforated domain embedded in the surface. The fluid entrapment system uses a cavity underneath the domain to allow entrapment of fluid of the same type, or supply air to the surface perforations in …

Microparticle Propulsion For In Vivo Navigation, Louis Rogowski

Mechanical Engineering Research Theses and Dissertations

Microscale propulsion impacts a diverse array of fields, with simplistic microrobots allowing for novel innovations in microscale surgery and drug delivery. Propulsion at the microscale is constrained by physics, with time-reversal and geometric symmetries limiting available propulsion mechanisms. However, certain fluid environments and surface coatings allow for the propulsion of microparticles through externally applied magnetic fields. Presented here is a detailed analysis of microparticles propelling using spontaneous symmetry breaking, flagella surface coatings, and multi-modal actuation mechanisms. Spontaneous symmetry breaking in nonlinearly viscoelastic fluids is presented for the first time in literature, with two equal and opposite propulsion states existing along …

Homogenization Of Composite And Cellular Materials Incorporating Microstructure And Surface Energy Effects, Ahmad Gad

Mechanical Engineering Research Theses and Dissertations

In the last few decades, the popularity of composite and cellular materials has rapidly increased through their widespread applications in multiple engineering fields including aerospace, automotive, civil and biomedical. However, to a large extent, the success of their practical applications depends on our ability to predict their mechanical behavior by using high-fidelity mechanics models.

Micromechanical modeling of composite and cellular materials is a challenging task due to the heterogeneous nature of such materials and the interactions among various constituent phases at the microscopic level, which result in non-homogeneous deformation, strain and stress fields. Therefore, it is necessary to develop simple …

Critical Point Identification In 3d Velocity Fields, Mohammadreza Zharfa

Mechanical Engineering Research Theses and Dissertations

Classification of flow fields involving strong vortices such as those from bluff body wakes and animal locomotion can provide important insight to their hydrodynamic behavior. Previous work has successfully classified 2D flow fields based on critical points of the velocity field and the structure of an associated weighted graph using the critical points as vertices. The present work focuses on extension of this approach to 3D flows. To this end, we have used the Gauss-Bonnet theorem to find critical points and their indices in the 3D velocity vector field, which functions similarly to the Poincare-Bendixon theorem in 2D flow fields. …

Graphene-Based Water Desalination Using Atomistic Simulations, Thanh Chinh Nguyen

Mechanical Engineering Research Theses and Dissertations

My research focused on investigating saltwater transport through nanoporous graphene membranes using molecular dynamics (MD) simulations. Particularly, in this dissertation, we focused on pressure-driven flows of salt water through uncharged and charged nanoporous graphene membranes for water desalination applications. In the first study, desalination performance of uncharged single-layer nanoporous graphene membranes was observed based on volumetric flow rate, required pressure drop, and salt rejection efficiency. A functional relationship between the volumetric flow rate, pressure drop, pore diameter, and the dynamic viscosity of saltwater was also examined. In further studies, transport of salt ions through positively and negatively charged single-layer nanoporous …

Molecular Dynamics Studies On Nanoscale Confined Liquids, Alper Celebi

Mechanical Engineering Research Theses and Dissertations

Liquid transport in nanochannels have been attracting great interests, especially for last two decades, owing to its potential applicability in various fields including biochemistry, medical science and engineering. For exploring and generating new ideas in the field of nanofluidics, molecular simulation techniques have become an ideal way due to the experimental challenges impeding the field of nanofluidics in fabrication and measurements.

In this dissertation, we perform molecular dynamics simulations to investigate liquid transport behavior in nanoscale channels. The expanse of this dissertation concerns several fundamental topics in nanoscale liquid transport phenomena such as liquid properties in nanoscale confinements, interfacial flows …