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Full-Text Articles in Mechanical Engineering

Multiscale Numerical Analysis Of Airflow In Ct-Based Subject Specific Breathing Human Lungs, Jiwoong Choi Dec 2011

Multiscale Numerical Analysis Of Airflow In Ct-Based Subject Specific Breathing Human Lungs, Jiwoong Choi

Theses and Dissertations

An imaging-based computational framework for simulation of airflow in subject specific breathing human lungs is established. The three-dimensional (3D) airways of up to 9 generations and lobes are segmented and reconstructed from computed tomography (CT) images. Beyond the CT-resolved 3D airways, a volume filling method is applied to generate the one-dimensional (1D) conducting airway tree that bridges the central airway with the lung parenchyma. Through 3D-1D airway coupling, a novel image-registration-based boundary condition (BC) is proposed to derive physiologically-consistent regional ventilation for the whole lung and provide flow-rate fractions needed for the 3D airway model via the 1D-tree connectivity and ...


Influence Of Supraglottal Geometry And Modeling Choices On The Flow-Induced Vibration Of A Computational Vocal Fold Model, Timothy E. Shurtz Nov 2011

Influence Of Supraglottal Geometry And Modeling Choices On The Flow-Induced Vibration Of A Computational Vocal Fold Model, Timothy E. Shurtz

Theses and Dissertations

Computational models of the flow-induced vibrations of the vocal folds are powerful tools that can be used in conjunction with physical experiments to better understand voice production. This thesis research has been performed to contribute to the understanding of vocal fold dynamics as well as several aspects of computational modeling of the vocal folds. In particular, the effects of supraglottal geometry have been analyzed using a computational model of the vocal folds and laryngeal airway. In addition, three important computational modeling parameters (contact line location, Poisson's ratio, and symmetry assumptions) have been systematically varied to determine their influence on ...


Thermal Comparison Between Ceiling Diffusers And Fabric Ductwork Diffusers For Green Buildings, Anthony Fontanini, Michael Olsen, Baskar Ganapathysubramanian Nov 2011

Thermal Comparison Between Ceiling Diffusers And Fabric Ductwork Diffusers For Green Buildings, Anthony Fontanini, Michael Olsen, Baskar Ganapathysubramanian

Mechanical Engineering Publications

Continuously increasing energy standards have driven the need for increasing the efficiency of buildings. Most enhancements to building efficiency have been a result of changes to the heating/cooling systems, improvements in construction materials, or building design code improvements. These approaches neglect the way in which air is dispersed into individual rooms or in a building – i.e., the ducting system. This opens up the possibility of significant energy savings by making ductwork systems lighter and better insulating while ensuring cost effectiveness.

The current study explores this idea by comparing the performance of conventional ductwork with recent advancements in fabric-based ...


California Polytechnic State University Wind Resource Assessment, Jason Allan Smith Sep 2011

California Polytechnic State University Wind Resource Assessment, Jason Allan Smith

Master's Theses and Project Reports

Wind resource assessment at California Polytechnic State University shows there is potential for wind power generation on Cal Poly land. A computational fluid dynamics model based on wind data collected from a campus maintained meteorological tower on Escuela Ranch approximately 5 miles northwest of campus suggests there are areas of Cal Poly land with an IEC Class III wind resource at a height of 80 meters above ground. In addition during the daytime when the campus uses the most energy there are large portions of land with annual average daytime wind speeds above 6.9m/s. These areas have been ...


Cavitation From A Butterfly Valve: Comparing 3d Simulations To 3d X-Ray Computed Tomography Flow Visualization, Graham Brett, Marc Riveland, Terrence C. Jensen, Theodore J. Heindel Jul 2011

Cavitation From A Butterfly Valve: Comparing 3d Simulations To 3d X-Ray Computed Tomography Flow Visualization, Graham Brett, Marc Riveland, Terrence C. Jensen, Theodore J. Heindel

Mechanical Engineering Conference Presentations, Papers, and Proceedings

Flow control valves may experience localized cavitation when the local static pressure drops to the liquid vapor pressure. Localized damage to the valve and surrounding area can occur when the vapor cavity collapses. Valve designs that reduce cavitation are based on empirical evidence and accumulated experience, but there are still considerable cavitation problems in industry. Valve designers may use computational fluid dynamics (CFD) to simulate cavitation in flow control valves, but model validation is challenging because there are limited data of local cavitation from the valve surface. Typically, the intensity of cavitation in a control valve is inferred from measurements ...


Fluid Dynamics Of Cell Printing, Ping He May 2011

Fluid Dynamics Of Cell Printing, Ping He

All Dissertations

Cell printing is an emerging technology that uses droplets to deliver cells to desired positions with resolution potentially comparable to the size of single cells. In particular, ink–jet based cell printing technique has been successfully used to build simple bio–constructs and has shown a promise in building complex bio–structures or even organs. Two important issues in ink–jet based cell printing are the moderate survival rate of delicate cells and the limited cell placement resolution. Resolving these issues is critical for the ink–jet based cell printing techniques to realize their full potential.
In this work, we ...


Multidimensional Modeling Of Condensing Two-Phase Ejector Flow, Michael F. Colarossi Jan 2011

Multidimensional Modeling Of Condensing Two-Phase Ejector Flow, Michael F. Colarossi

Masters Theses 1911 - February 2014

Condensing ejectors utilize the beneficial thermodynamics of condensation to produce an exiting static pressure that can be in excess of either entering static pressure. The phase change process is driven by both turbulent mixing and interphase heat transfer. Semi-empirical models can be used in conjunction with computational fluid dynamics (CFD) to gain some understanding of how condensing ejectors should be designed and operated.

The current work describes the construction of a multidimensional simulation capability built around an Eulerian pseudo-fluid approach. The transport equations for mass and momentum treat the two phases as a continuous mixture. The fluid is treated as ...


Multi-Objective Optimization Based Engineering Decision Tool, Adam Joe Shuttleworth Jan 2011

Multi-Objective Optimization Based Engineering Decision Tool, Adam Joe Shuttleworth

Graduate Theses and Dissertations

Prior to the acceptance of computer aided engineering (CAE) software in the product development process (PDP), product development was characterized by a design-test-redesign-test cycle. This activity was time consuming and resource intensive. As CAE software tools have been integrated into the PDP, the PDP can be characterized by a design-simulate-redesign-test cycle. The addition of CAE tools to the PDP has reduced the time to market and resource consumption.

In the last decade, CAE software has become easier to use and computer power has increased such that CAE software is more widely used in the PDP. In parallel, there has been ...