Open Access. Powered by Scholars. Published by Universities.®

Aerodynamics and Fluid Mechanics Commons

Open Access. Powered by Scholars. Published by Universities.®

927 Full-Text Articles 1,276 Authors 784,390 Downloads 80 Institutions

All Articles in Aerodynamics and Fluid Mechanics

Faceted Search

927 full-text articles. Page 7 of 40.

Complicating Factors In Hydraulic Jumps: The Effects Of Earth's Rotation, Muveno Pascoal Elias Mucaza 2021 The University of Western Ontario

Complicating Factors In Hydraulic Jumps: The Effects Of Earth's Rotation, Muveno Pascoal Elias Mucaza

Electronic Thesis and Dissertation Repository

Hydraulic jumps at the interface of stratified rotating fluids are studied. The flow is de- fined with continuous density and velocity profiles, with the velocity in each layer changing (upstream shear). The study is conducted in jumps defined by an imposed velocity transition, and jumps developing over a topography.

The numerical simulations conducted showed the qualitative structure of the flow changing in the cross-width direction, as well as the size and amount of turbulence of the jumps. Mixing in these jumps was shown to increase towards the side of the domain where the jumps were larger and more turbulent. The …


Blade Optimization For Ground Level Low Speed Wind Turbines, Ryan Foster 2021 Kennesaw State University

Blade Optimization For Ground Level Low Speed Wind Turbines, Ryan Foster

Symposium of Student Scholars

Low speed wind turbines can provide inexpensive and clean energy in areas where large scale wind power generation is impractical. The purpose of this research is to explore factors that affect the efficiency of low speed wind turbine blades. The factors that were tested include angle of attack, angle of twist, chord length, average thickness, span, and taper ratio. The goal is to determine a combination of these variables to enable maximum power extraction from a low wind speed source. These blade parameters are optimized for the Southeastern region of the United States. NOAA weather data at ground level are …


Lifting Flow Over A Cylinder As A Lift System, Kyle Mello 2021 Kennesaw State University

Lifting Flow Over A Cylinder As A Lift System, Kyle Mello

Symposium of Student Scholars

The goal of this project is to conceptually design a lift system consisting of rotating cylinders that may improve certain flight characteristics when compared to conventional wings for a typical two passenger airplane. The functions of flaps, ailerons, lift to weight ratio and structural responses are considered. The cylindrical model is developed within CFD simulation software such that it generates the same lift produced by the wings of a Cessna 172 wings at cruising speed. Incompressible flow theoretical solutions are initially shown to compare favorably with the computational predictions for elementary cylindrical designs.

The rotating cylinder aircraft generates the same …


Modeling And Design Optimization For Membrane Filters, YiXuan Sun 2021 New Jersey Institute of Technology

Modeling And Design Optimization For Membrane Filters, Yixuan Sun

Dissertations

Membrane filtration is widely used in many applications, ranging from industrial processes to everyday living activities. With growing interest from both industrial and academic sectors in understanding the various types of filtration processes in use, and in improving filter performance, the past few decades have seen significant research activity in this area. Experimental studies can be very valuable, but are expensive and time-consuming, therefore theoretical studies offer potential as a cost-effective and predictive way to improve on current filter designs. In this work, mathematical models, derived from first principles and simplified using asymptotic analysis, are proposed for: (1) pleated membrane …


Modeling Dewetting, Demixing, And Thermal Effects In Nanoscale Metal Films, Ryan Howard Allaire 2021 New Jersey Institute of Technology

Modeling Dewetting, Demixing, And Thermal Effects In Nanoscale Metal Films, Ryan Howard Allaire

Dissertations

Thin film dynamics, particularly on the nanoscale, is a topic of extensive interest. The process by which thin liquids evolve is far from trivial and can lead to dewetting and drop formation. Understanding this process involves not only resolving the fluid mechanical aspects of the problem, but also requires the coupling of other physical processes, including liquid-solid interactions, thermal transport, and dependence of material parameters on temperature and material composition. The focus of this dissertation is on the mathematical modeling and simulation of nanoscale liquid metal films, which are deposited on thermally conductive substrates, liquefied by laser heating, and subsequently …


The Influence Of Trailing Edge Shape And Kinematics On Bio-Inspired Pitching Panels, Justin Thomas King 2021 Syracuse University

The Influence Of Trailing Edge Shape And Kinematics On Bio-Inspired Pitching Panels, Justin Thomas King

Dissertations - ALL

Recently, some engineers have turned to the study of swimming and flying animals to provide insight into the design of vehicles that move through air or water. For certain animals swimming in water, thrust is generated primarily by either a caudal fin or fluke located at the posterior end of the swimmer. It has been argued extensively in the existing research literature that biological propulsors of high aspect ration that also display forked, or lunate, planforms are representative of optimized propulsor geometries with respect to propulsive performance. However, recent experimental and computational work on purely pitching panels has demonstrated that …


Active Control Of Coherent Structures In An Axisymmetric Jet, Michael Marques Goncalves 2021 Embry-Riddle Aeronautical University

Active Control Of Coherent Structures In An Axisymmetric Jet, Michael Marques Goncalves

Doctoral Dissertations and Master's Theses

The primary objective of this work is to develop high-fidelity simulation model for jet noise control predictions and quantify the sound reduction when an external source frequency mode excitation is imposed on the jet flow. Whereas passive approaches using mixing devices, such as chevrons, have been shown to reduce low-frequency noise in jet engines, such approaches incur a performance penalty since they result in a reduced thrust. To avoid a performance penalty in reducing jet noise, the current work investigates a open-loop active noise control (ANC) system that utilizes a unsteady microjet actuator on the nozzle lip in the downstream …


Background Flow Influence On Impulsive Jet-Driven Micro Droplet Dispersal, Vaishak Thiruvenkitam 2021 Embry-Riddle Aeronautical University

Background Flow Influence On Impulsive Jet-Driven Micro Droplet Dispersal, Vaishak Thiruvenkitam

Doctoral Dissertations and Master's Theses

Accurately predicting the airborne spread of infectious diseases is crucial in controlling the COVID­19 pandemic today. Studies have shown the spread of expiratory droplets depends on ambient thermodynamic conditions and flow properties of the jet emitted by the activity. However, the droplet spread in conditions of background flow is not yet comprehensively understood. This study uses the Eulerian­-Lagrangian model with k−ω turbulence modelling to simulate spread of particles and study the factors affecting it in a closed environment with a background flow. Respiratory activities are modeled as a non-­isothermal jet of air with droplets suspended in them in a predetermined …


Integral Boundary Layer Methods In Python, Malachi Joseph Edland 2021 California Polytechnic State University, San Luis Obispo

Integral Boundary Layer Methods In Python, Malachi Joseph Edland

Master's Theses

This thesis presents a modern approach to two Integral Boundary Layer methods implemented in the Python programming language. This work is based on two 2D boundary layer methods: Thwaites' method for laminar boundary layer flows and Head's method for turbulent boundary layer flows. Several novel enhancements improve the quality and usability of the results. These improvements include: a common ordinary differential equation (ODE) integration framework that generalizes computational implementations of Integral Boundary Layer methods; the use of a dense output Runge-Kutta ODE solver that allows for querying of simulation results at any point with accuracy to the same order as …


Fully Coupled Internal Radiative Heat Transfer For The 3d Material Response Of Heat Shield, Raghava S. C. Davuluri, Rui Fu, Kaveh A. Tagavi, Alexandre Martin 2021 University of Kentucky

Fully Coupled Internal Radiative Heat Transfer For The 3d Material Response Of Heat Shield, Raghava S. C. Davuluri, Rui Fu, Kaveh A. Tagavi, Alexandre Martin

Mechanical Engineering Faculty Publications

The radiative transfer equation (RTE) is strongly coupled to the material response code KATS. A P-1 approximation model of RTE is used to account for radiation heat transfer within the material. First, the verification of the RTE model is performed by comparing the numerical and analytical solutions. Next, the coupling scheme is validated by comparing the temperature profiles of pure conduction and conduction coupled with radiative emission. The validation study is conducted on Marschall et al. cases (radiant heating, arc-jet heating, and space shuttle entry), 3D Block, 2D IsoQ sample, and Stardust Return Capsule. The validation results agree well for …


An Analysis Of Capillary Flow In Finite Length Interior Corners, Samuel Shaw Mohler 2021 Portland State University

An Analysis Of Capillary Flow In Finite Length Interior Corners, Samuel Shaw Mohler

Dissertations and Theses

We analyze the mathematical robustness of slow massively parallel interior corner flows in low gravity environments. An interior corner provides a preferential orientation in low gravity environments. This is a luxury usually only found on earth. It also provides a passive pumping mechanism due to geometry of a conduit. The driving force for this flow is a pressure difference due to local surface curvature gradients. An alternative reasoning is that due to the geometrical constraints the interior corner surface energy is unbounded below. This results in the liquid wicking into corners indefinitely. Interior corner flow's main quantity of interest is …


Extracting Microplastic From Anhydrous Beach Sediment Utilizing Relative Terminal Velocities, Grace Robertson, Jackson Schuler 2021 Embry-Riddle Aeronautical University

Extracting Microplastic From Anhydrous Beach Sediment Utilizing Relative Terminal Velocities, Grace Robertson, Jackson Schuler

Student Works

The primary intent of this research was to investigate and develop a method to extract microplastics from anhydrous beach sediment. Microplastic is found abundantly in coastal sea environments, including aqueous bottom sediment, and beach sediment (Sagawa, Kawaai, & Hinata, 2018). The scope of the microplastic extraction method in this case is limited to strictly the anhydrous beach sediment. The Venturi Effect and Burnoulli’s Principle have been utilized in the design of a nozzle with airflow that has been injected with a sediment and microplastic heterogenous mixture. A nozzle was designed to operate at the specific terminal velocity of sediment such …


Fixed Bottom Wind Turbine Wave-Wake Interaction, Ondrej Fercak 2021 Portland State University

Fixed Bottom Wind Turbine Wave-Wake Interaction, Ondrej Fercak

Dissertations and Theses

The interest and benefits of offshore wind energy has also brought along legitimate design challenges for engineers. Most notably, the complex interaction between wind and turbine is further complicated by the addition of dynamic ocean waves. This dynamic coupling between wind, wave, and turbine is not fully understood. Even small improvements in wind turbine performance are welcome, so characterizing a fundamental dynamic in offshore energy is necessary to optimize design. Experimentation and simulation have been used to characterize inflow and turbine wakes and separately, wind-wave interactions. But only simulations have just begun to look at the wind, wave, and turbine …


Design And Flight-Path Simulation Of A Dynamic-Soaring Uav, Gladston Joseph 2021 Embry-Riddle Aeronautical University

Design And Flight-Path Simulation Of A Dynamic-Soaring Uav, Gladston Joseph

Doctoral Dissertations and Master's Theses

We address the development of a dynamic-soaring capable unmanned aerial vehicle (UAV) optimized for long-duration flight with no on-board power consumption. The UAV’s aerodynamic properties are captured with the integration of variable fidelity aerodynamic analyses. In addition to this, a 6 degree-of-freedom flight simulation environment is designed to include the effects of atmospheric wind conditions. A simple flight control system aids in the development of the dynamic soaring maneuver. A modular design paradigm is adopted for the aircraft dynamics model, which makes it conducive to use the same environment to simulate other aircraft models. Multiple wind-shear models are synthesized to …


Analysis Of A Non-Equilibrium Vortex Pair As Aircraft Trailing Vortices, Manuel Ayala 2021 Old Dominion University

Analysis Of A Non-Equilibrium Vortex Pair As Aircraft Trailing Vortices, Manuel Ayala

Mechanical & Aerospace Engineering Theses & Dissertations

Shortly after the roll-up evolution of the vortex sheet behind the wings of an aircraft, a coherent counter-rotating vortex pair emerges. Presence of this vortex pair in the downstream of an aircraft, creates unsafe conditions for other aircraft, especially near airport runways. Fundamental knowledge of the physics that govern the formation, duration and dissipation of aircraft wake vortices is desirable in order to improve aircraft operational safety. This study uses non-equilibrium pressure theory to develop an accurate model describing the physical behavior of the vortex pair created by an aircraft in the early to mid-field vortex regime. An isolated aircraft …


Fluid-Structure Interaction Of Nrel 5-Mw Wind Turbine, Mohamed Sayed Elkady Abd-Elhay 2021 The American University in Cairo AUC

Fluid-Structure Interaction Of Nrel 5-Mw Wind Turbine, Mohamed Sayed Elkady Abd-Elhay

Theses and Dissertations

Wind energy is considered one of the major sources of renewable energy. Nowadays, wind turbine blades could exceed 100 m to maximize the generated power and minimize produced energy cost. Due to the enormous size of the wind turbines, the blades are subjected to failure by aerodynamics loads or instability issues. Also, the gravitational and centrifugal loads affect the wind turbine design because of the huge mass of the blades. Accordingly, wind turbine simulation became efficient in blade design to reduce the cost of its manufacturing. The fluid-structure interaction (FSI) is considered an effective way to study the turbine's behavior …


Bibliometric Analysis On Artificial Compressibility Method Based Cfd Simulations, Bhavna Hemraj Joshi Miss, Chandrakant R. Sonawane Dr, Priyambada bada Praharaj Mrs, Anand Kumar Pandey Dr 2021 Symbiosis Institute of Technology, Symbiosis International Deemed University, India

Bibliometric Analysis On Artificial Compressibility Method Based Cfd Simulations, Bhavna Hemraj Joshi Miss, Chandrakant R. Sonawane Dr, Priyambada Bada Praharaj Mrs, Anand Kumar Pandey Dr

Library Philosophy and Practice (e-journal)

This bibliometric analysis in this paper aims to study the quantitative progress done in the artificial compressibility (AC) method-based CFD simulation and analyze its potential in solving incompressible flow simulations in computational fluid dynamics smoothly. The sector of CFD is enhancing more and more maturely due to advancements in computing architecture, numerical methods, and simulation tools. There have been various attempts to solve the pressure-velocity coupling issue in the Navier-Stokes equation. The artificial compressibility method (ACM), as opposed to pressure-correction methods, solves the incompressible equation in a non-segregated manner. With the introduction of the ACM, the system of the equation …


A Flat Plate Skin Friction Correlation Including Transition, Jaret M. Wedow 2021 California Polytechnic State University, San Luis Obispo

A Flat Plate Skin Friction Correlation Including Transition, Jaret M. Wedow

Master's Theses

Many existing boundary layer models treat transition as a rapid switch from laminar to turbulent flow, with correlations defining properties in each respective region. Natural transition, however, is not always a very spanwise uniform process, with the onset of transition varying somewhat between different streamwise paths of fluid flow. Thus, a spanwise average of natural transition can result in a more gradual, extended transition region than many existing models predict. Modern applications, such as aircraft wings and fuselages, are extremely streamlined and smooth, allowing for natural transition to occur rather than flow tripping to turbulent near the leading edge. Under …


Perfromance Improvement Of High Bypass Turbofan Engine Through Optimization Of High-Pressure Compressor Blade – A Case Study, Vlad Mandzyuk 2021 Kennesaw State University

Perfromance Improvement Of High Bypass Turbofan Engine Through Optimization Of High-Pressure Compressor Blade – A Case Study, Vlad Mandzyuk

Symposium of Student Scholars

This research determines the relation between the High-Pressure Compressor (HPC) blade characteristics, compressor pressure ratio, and lift-to-drag ratio of a high bypass turbofan engine. Alterations in the HPC blades airfoil, span, chord, taper ratio, twist, aspect ratio, sweep, and angle of incidence are performed and their effect on the engine’s performance is observed. The metrics used to compare engine performance include thrust, specific thrust, exit velocity, fuel/air ratio, power, and efficiency. Parametric cycle analysis and computational fluid dynamics are performed to compare and validate findings. The goal of this study is to optimize the design of HPC to maximize the …


Numerical Simulation Of Flow Past An Airfoil With Ice Accretion On Leading Edge, Boyu Wang 2021 Washington University in St. Louis

Numerical Simulation Of Flow Past An Airfoil With Ice Accretion On Leading Edge, Boyu Wang

McKelvey School of Engineering Theses & Dissertations

The focus of this research is on aerodynamic simulation of flow past NACA 23012 airfoil with clean surface and with ice accretion on its leading edge by using the commercial CFD solver ANSYS Fluent. Reynolds-Averaged Navier-Stokes (RANS) computations are performed using Spalart-Allmaras (SA) and Wray-Agarwal (WA) turbulence models. ANSYS mesh package ICEM is used to model the geometry and generate the mesh. The computations are performed at 0, 2, 4, 6, 8, 10, and 12 degrees angle of attack which are compared with experimental data. For the case of ice accretion at the leading edge, the physical geometry becomes more …


Digital Commons powered by bepress