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Computational fluid dynamics

2016

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Articles 1 - 8 of 8

Full-Text Articles in Mechanical Engineering

Hydrodynamics Of Swimming Microorganisms In Complex Fluids, Gaojin Li Dec 2016

Hydrodynamics Of Swimming Microorganisms In Complex Fluids, Gaojin Li

Open Access Dissertations

Swimming motion of microorganisms, such as spermatozoa, plankton, algae and bacteria, etc., ubiquitously occurs in nature. It affects many biological processes, including reproduction, infection and the marine life ecosystem. The hydrodynamic effects are important in microorganism swimming, their nutrient uptake, fertilization, collective motions and formation of colonies. In nature, microorganisms have evolved to use various fascinating ways for locomotion and transport. Different designs are also developed for the locomotion of artificial nano- and microswimmers. In this study, we use several different computational models to investigate the behavior of microswimmers.

Microorganisms typically swim in the low Reynolds number regime, where inertia ...


Computational Fluid Dynamic Analysis Of Microbubble Drag Reduction Systems At High Reynolds Number, John D. Goolcharan Jul 2016

Computational Fluid Dynamic Analysis Of Microbubble Drag Reduction Systems At High Reynolds Number, John D. Goolcharan

FIU Electronic Theses and Dissertations

Microbubble drag reduction (MBDR) is an effective method to improve the efficiency of fluid systems. MBDR is a field that has been extensively studied in the past, and experimental values of up to 80% to 90% drag reduction have been obtained. The effectiveness and simplicity of MBDR makes it a viable method for real world applications, particularly in naval applications where it can reduce the drag between the surface of ships and the surrounding water. A two dimensional single phase model was created in ANSYS Fluent to effectively model the behavior of bubble laden flow over a flat plate. This ...


Implementations Of Fourier Methods In Cfd To Analyze Distortion Transfer And Generation Through A Transonic Fan, Marshall Warren Peterson Jun 2016

Implementations Of Fourier Methods In Cfd To Analyze Distortion Transfer And Generation Through A Transonic Fan, Marshall Warren Peterson

Theses and Dissertations

Inlet flow distortion is a non-uniform total pressure, total temperature, or swirl (flow angularity) condition at an aircraft engine inlet. Inlet distortion is a critical consideration in modern fan and compressor design. This is especially true as the industry continues to increase the efficiency and operating range of air breathing gas turbine engines. The focus of this paper is to evaluate the Computational Fluid Dynamics (CFD) Harmonic Balance (HB) solver in STAR-CCM+ as a reduced order method for capturing inlet distortion as well as the associated distortion transfer and generation. New methods for quantitatively describing and analyzing distortion transfer and ...


A Reduced Order Model For Efficient Physiological Flow Analysis In Aneurysms By Proper Orthogonal Decomposition, Gary Han Chang, Yahya Modarres-Sadeghi May 2016

A Reduced Order Model For Efficient Physiological Flow Analysis In Aneurysms By Proper Orthogonal Decomposition, Gary Han Chang, Yahya Modarres-Sadeghi

UMass Center for Clinical and Translational Science Research Retreat

Simulating physiological flows using computational fluid dynamics (CFD) remains to be computationally expensive and difficult for clinical usage because of the physiological flow and geometrical complexity involved in patient specific situations. We use the reduced order modeling (ROM) of such systems with high nonlinearity and geometrical non-uniformity to replace the full, nonlinear model with a low-degrees of freedom ROM model. We construct ROM models by the proper orthogonal decomposition (POD) method to estimate the flow-induced wall shear stress (WSS) and pressure loading of a simplified abdominal aortic aneurysm and a bifurcation cerebral aneurysm. This method allows us to investigate a ...


An Integrated Experimental-Computational Investigation Of Connected Spaces As Natural Ventilation Typologies, Ulrike Passe, Baskar Ganapathysubramanian, Shan He, Kyle Vansice, Songzhe Xu May 2016

An Integrated Experimental-Computational Investigation Of Connected Spaces As Natural Ventilation Typologies, Ulrike Passe, Baskar Ganapathysubramanian, Shan He, Kyle Vansice, Songzhe Xu

Architecture Conference Proceedings and Presentations

This paper investigates the impact of spatial composition on the effectiveness of passive cooling by natural ventilation in a comparative study of the conical roofed Harran houses in Turkey and a passive solar home in the Midwest of the United States. While the projects are distinct and are situated in two extreme climate zones (hot and arid and continental humid) both projects have in common open variable configurations of multiple interconnected spaces. Computational fluid dynamics (CFD) simulations using OpenFoam were used to investigate the fundamental airflow characteristics and the resulting interior temperature and velocity profiles. The simulations were initialized as ...


Cfd Model For Ventilation In Broiler Holding Sheds, Christian Heymsfield May 2016

Cfd Model For Ventilation In Broiler Holding Sheds, Christian Heymsfield

Biological and Agricultural Engineering Undergraduate Honors Theses

Broiler production in Arkansas was valued at over $3.6 billion in 2013 (University of Arkansas Extension of Agriculture). Consequently, improvement in any phase of the production process can have significant economic impact and animal welfare implications. From the time poultry leave the farm and until they are slaughtered, they can be exposed to harsh environmental conditions, both in winter and in summer. After road transportation, birds are left to wait in holding sheds once they arrive at the processing plant, for periods of approximately 30 minutes to two hours. This project was interested in this holding shed waiting time ...


Improving Ventricular Catheter Design Through Computational Fluid Dynamics, Sofy Hefets Weisenberg May 2016

Improving Ventricular Catheter Design Through Computational Fluid Dynamics, Sofy Hefets Weisenberg

Masters Theses

Cerebrospinal fluid (CSF) shunts are fully implantable medical devices that are used to treat patients suffering from conditions characterized by elevated intracranial pressure, such as hydrocephalus. In cases of shunt failure or malfunction, patients are often required to endure one or more revision surgeries to replace all or part of the shunt. One of the primary causes of CSF shunt failure is obstruction of the ventricular catheter, a component of the shunt system implanted directly into the brain's ventricular system. This work aims to improve the design of ventricular catheters in order to reduce the incidence of catheter obstruction ...


Analysis Of High Fidelity Turbomachinery Cfd Using Proper Orthogonal Decomposition, Ronald Alex Spencer Mar 2016

Analysis Of High Fidelity Turbomachinery Cfd Using Proper Orthogonal Decomposition, Ronald Alex Spencer

Theses and Dissertations

Assessing the impact of inlet flow distortion in turbomachinery is desired early in the design cycle. This thesis introduces and validates the use of methods based on the Proper Orthogonal Decomposition (POD) to analyze clean and 1/rev static pressure distortion simulation results at design and near stall operating condition. The value of POD comes in its ability to efficiently extract both quantitative and qualitative information about dominant spatial flow structures as well as information about temporal fluctuations in flow properties. Observation of the modes allowed qualitative identification of shock waves as well as quantification of their location and range ...