Aerodynamics and Fluid Mechanics Commons^™

Many-Objective Hybrid Optimization Under Uncertainty With Applications, Sohail Reddy

FIU Electronic Theses and Dissertations

A novel method for solving many-objective optimization problems under uncertainty was developed. It is well known that no single optimization algorithm performs best for all problems. Therefore, the developed method, a many-objective hybrid optimizer (MOHO), uses five constitutive algorithms and actively switches between them throughout the optimization process allowing for robust optimization. MOHO monitors the progress made by each of the five algorithms and allows the best performing algorithm more attempts at finding the optimum. This removes the need for user input for selecting algorithm as the best performing algorithm is automatically selected thereby increasing the probability of converging to …

A Constructal Approach To The Design Of Inflected Airplane Wings, Shanae Powell

FIU Electronic Theses and Dissertations

Aeroelastic instabilities such as flutter can be accurately captured by state-of-the-art aeroelastic analysis methods and tools. However, these tools and methods fall short in exposing the reasons behind the occurrence of such instabilities. In this research, the constructal law is used to discover the main cause of the variation in the flutter speed and stress distribution for inflected aircraft wings when compared to its uninflected counterpart. This law considers the design as a physics phenomenon and uses an evolutionary flow principle to explain and predict the occurrence of energy flow configurations (i.e. the flow of stresses throughout the structure).

For …

Numerical Simulation Of Flushing Deposits In Pipelines, Joseph S. Coverston

FIU Electronic Theses and Dissertations

The purpose of this research is to reduce the amount of waste generated in Department of Energy nuclear cleanup efforts currently underway. Due to the highly radioactive nature of the waste, any fluid that contacts the waste must then be treated and processed as waste. To minimize the fluids contaminated during flushing, this research aims to provide a basis for the flushing of High Level Waste (HLW) pipelines. Edgar Plastic Kaolin (EPK) with solid particles of a nominal diameter of 1 micron was used as a simulacrum for HLW. An Eulerian-Eulerian simulation built in StarCCM+ software, with a k-ω turbulence …

Investigating Scale Effects On Analytical Methods Of Predicting Peak Wind Loads On Buildings, Mohammadtaghi Moravej

FIU Electronic Theses and Dissertations

Large-scale testing of low-rise buildings or components of tall buildings is essential as it provides more representative information about the realistic wind effects than the typical small scale studies, but as the model size increases, relatively less large-scale turbulence in the upcoming flow can be generated. This results in a turbulence power spectrum lacking low-frequency turbulence content. This deficiency is known to have significant effects on the estimated peak wind loads.

To overcome these limitations, the method of Partial Turbulence Simulation (PTS) has been developed recently in the FIU Wall of Wind lab to analytically compensate for the effects of …

Investigation Of Low Reynolds Number Flow And Heat Transfer Of Louvered Surfaces, Pradeep R. Shinde

FIU Electronic Theses and Dissertations

This study focuses on the investigation of flow behavior at low Reynolds numbers by the experimental and numerical performance testing of micro-channel heat exchangers. An experimental study of the heat transfers and pressure drop of compact heat exchangers with louvered fins and flat tubes was conducted within a low air-side Reynolds number range of 20 < Re_Lp < 225. Using an existing low-speed wind tunnel, 26 sample heat exchangers of corrugated louver fin type, were tested. New correlations for Colburn j and Fanning friction f factor have been developed in terms of non-dimensional parameters. Within the investigated parameter ranges, it seems that both the j and f factors are better represented by two correlations in two flow regimes (one for Re_Lp = 20 – 80 and one for Re_Lp = 80 – 200) than a single regime correlation in the power-law format. The results support the conclusion that airflow and heat transfer at very low Reynolds numbers behaves differently from that …

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 …

Multi-Objective Analysis And Optimization Of Integrated Cooling In Micro-Electronics With Hot Spots, Sohail R. Reddy

FIU Electronic Theses and Dissertations

With the demand of computing power from electronic chips on a constant rise, innovative methods are needed for effective and efficient thermal management. Forced convection cooling through an array of micro pin-fins acts not only as a heat sink, but also allows for the electrical interconnection between stacked layers of integrated circuits. This work performs a multi-objective optimization of three shapes of pin-fins to maximize the efficiency of this cooling system. An inverse design approach that allows for the design of cooling configurations without prior knowledge of thermal mapping was proposed and validated. The optimization study showed that pin-fin configurations …