Aerodynamics and Fluid Mechanics Commons^™

Characterization, Design, And Optimization Of Dual-Purpose Wind Turbines And Frost Protection Fans, Ethan Narad

Master's Theses

This thesis report outlines the creation of a MATLAB tool to design reversible machines that can function as both wind turbines and as agricultural frost protection fans. Frost protection fans are used to prevent crop loss during radiative freeze events during which a temperature inversion is present. Such a dual-purpose machine fundamentally has the constraint that it must use symmetric airfoils, so a suite of tools for automatically designing an optimized wind turbine blade with symmetric airfoils using the Blade Element Momentum (BEM) theory approach is presented. The BEM code is then re-derived and adapted for use with a frost …

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 …

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 …

Computational Investigation Of Perforated Plate Film Cooling Utilizing Conjugate Heat Transfer, Jonathan Sippel

Doctoral Dissertations and Master's Theses

The accuracy of modern state-of-practice computational fluid dynamics approaches in predicting the cooling effectiveness of a perforated plate film-cooling arrangement is evaluated in ANSYS Fluent. A numerical investigation is performed using the Reynolds Averaged Navier Stokes equations and compared to NASA Glenn’s available Turbulent Heat Flux 4 experimental measurements collected as a part of the Transformational Tools and Technologies Project. A multiphysics approach to model heat conduction through the solid geometry is shown to offer significant improvements in wall temperature and film effectiveness prediction accuracy over the standard adiabatic wall approach. Additionally, localized gradient-based grid adaption is analyzed using the …

Bicycle Wheel Aerodynamics Predictions Using Cfd: Efficiency Using Blade Element Method, Drew Vigne

Honors Undergraduate Theses

The cycling industry has long relied on expensive wind tunnel testing when designing aerodynamic products, particularly in the context of wheels which account for 10 to 15 percent of a cyclist's total aerodynamic drag. With the recent advent of Computational Fluid Dynamics (CFD), the industry now has an economical tool to supplement the wheel design process; however, the complex nature of rotating spoked wheels requires high resolution meshes to model at acceptable fidelity. This research investigates an alternative CFD method that lowers the computational cost of modeling aerodynamic bicycle wheels by modeling spokes using Blade Element Method (BEM). Two CFD …

Next-Generation Re-Entry Aerothermodynamic Modeling Of Space Debris Using Machine Learning, Nicholas Sia

Graduate Theses, Dissertations, and Problem Reports (ETD)

The number of resident space objects re-entering the atmosphere is expected to rise with increased space activity over recent years and future projections. Predicting the survival and impact location of the medium to large sized re-entering objects becomes important as they can cause on ground casualties and damage to property. Uncertainties associated with the re-entry process makes necessary a probabilistic approach, which can be computationally expensive when using high-fidelity numerical methods for estimating aerothermodynamic properties. To date, object-oriented analysis is the dominant tool used for atmospheric re-entry modeling and simulation, where aerothermodynamic coefficients are used to determine the risk a …

Identification Of Wind-Induced Hazard Zones Impacting Uas Bridge Inspection, Jack J. Green, John Mott

International Journal of Aviation, Aeronautics, and Aerospace

Unmanned Aerial Systems (UAS) continue to grow in both popularity and utility within the national airspace system. The use of commercial UAS for civil inspection, specifically that of bridge structures, is becoming commonplace among practitioners and academics alike. The development of an integrated bridge-inspection hazard model provides a way for UAS operators to prepare for and respond to changing environmental conditions that could otherwise prevent a successful UAS flight. The interaction of wind-induced airflow with bridge surfaces creates an aerodynamic wake that can result in hazardous conditions for a UAS platform operating in close proximity. An analysis of this airflow …

Comparative Study On Performance Accuracy Of Three Probe And Five Probe Flow Analysers For Wind Tunnel Testing, Akhila Rupesh Ms, J V Muruga Lal Jeyan Dr

International Journal of Aviation, Aeronautics, and Aerospace

In the field of inviscid fluid flow studies, the theoretical concept has to be developed even more. In order to make it possible, it is very important to supplement the concepts with strong experimental results. While performing experimentation, various accepts of design can be determined with factors influencing the and also required modification can be recommended in a more systematic and economic manner. Also, the aim objective of the experiment is to extend the underlying theory and to produce new designs with improvements that can be great support to the advancement in technology. In experimental analysis, wind tunnels are used …

Field Testing The Effects Of Low Reynolds Number On The Power Performance Of The Cal Poly Wind Power Research Center Small Wind Turbine, John B. Cunningham

Master's Theses

This thesis report investigates the effects of low Reynolds number on the power performance of a 3.74 m diameter horizontal axis wind turbine. The small wind turbine was field tested at the Cal Poly Wind Power Research Center to acquire its coefficient of performance, C­_p, vs. tip speed ratio, λ, characteristics. A description of both the wind turbine and test setup are provided. Data filtration and processing techniques were developed to ensure a valid method to analyze and characterize wind power measurements taken in a highly variable environment. The test results demonstrated a significant drop in the …

Numerical Analysis Of A Circulation Control Wing, Luke W. Bodkin

Master's Theses

The objective of this thesis was to develop an experimental method to research circulation control wings using numerical analysis. Specifically, it is of interest to perform 3D wind tunnel testing on a circulation control wing in the Cal Poly Low Speed Wind Tunnel (CPLSWT). A circulation control wing was designed and analyzed to determine the feasibility of this testing.

This study relied on computational fluid dynamics (CFD) simulations as a method to predict the flow conditions that would be seen in a wind tunnel test. A CFD simulation was created of a wing model in a wind tunnel domain. Due …

Avia 201 Project 1 Windtunnel Lab Form Ver 1.20 20200323, Nihad E. Daidzic

Aviation Department Publications

To introduce aviation/aeronautics/aerospace students to wind tunnel(s) and methods used in experimental identification of various aerodynamic (and stability) coefficients of airfoils (2D), wings (3D) and scale models.

A Cfd Study Investigating Drag Reduction For Different Offset And Inline Distance For Two Trucks Platooning, Wael Mokhtar, Kyle Dinger, Shardul Kachare, Mdrazib Hossain, Colin Britcher

Mechanical & Aerospace Engineering Faculty Publications

The automotive industry invests huge resources to improve fuel consumption of commercial vehicles by improving their aerodynamic efficiency. Recently, numerous studies investigating the effect of platooning on aerodynamic drag of semi-trucks have been performed by researchers indicating a positive impact. For the present study, a three-dimensional computational study was performed to investigate the effect of varying offset and linear distance during platooning on the total drag of two semi-trucks. The study was conducted on a full-scale model using Reynold’s Averaged Navier-Strokes governing equations for a moving ground simulation using the STAR-CCM+ computational package. Furthermore, for turbulence, the standard k- …

Design, Construction And Testing Of A 3-Component Force Balance For Educational Wind Tunnels In Undergraduate Aerodynamics, Milan Tomin, Marco Scipioni, Benjamin Gatti

Journal of Aviation/Aerospace Education & Research

This article is focused on providing detailed instructions on how to build and use a force balance for educational wind tunnels. The article’s objective is to encourage undergraduate students in underfunded programs to engage in the field of aerodynamics. The discussed force balance represents an affordable device that only requires basic components like Arduino board, a servo motor, and acrylic and aluminum as construction materials. A simple data collection example is included at the end of the article showing that this simple force balance can collect meaningful data about lift, drag, and moment coefficient of a tested airfoil.

Experimental And Computational Evaluation Of Five Hole Five Probe Flow Analyzer For Subsonic Wind Calibration, Akhila Rupesh Ms, J V Muruga Lal Jeyan Dr

International Journal of Aviation, Aeronautics, and Aerospace

It is very essential to predict the flow and its related parameters to understand real life fluid flow. The real-life fluid problems are studied with wind tunnels which gives very efficient results in practice. But in the case of wind tunnel studies flow angularities plays crucial role. Flow angularity determination includes measurement of static pressure, dynamic pressure and inflow angles. Flow prediction even hold a very strong hand in design process. Designing and testing being the foundation of any process industry, flow measurements and its related parameters have to be well evaluated. In such cases, wind tunnels play important role …

Unsteady Aerodynamic Analysis Of Wind Harvesting Aircraft, Judd Mehr, Eduardo Alvarez, Andrew Ning

Faculty Publications

Airborne Wind Energy (AWE) technology aspires to provide increased options for wind energy harvesting. This includes increased feasibility for temporary and remote installations, as well as the ability to operate at wind speeds both lower and higher than traditional turbines. Additionally, the hope is to be able to produce these extensions of wind energy technology at a lower cost than conventional technologies. As AWE technology is still in its infancy, however, there is very little published information concerning the aerodynamic details of the technology. We have created a set of aerodynamic analysis tools which we apply to wind harvesting aircraft, …

Wind Tunnel Measurements And Data Analysis Tutorial, Nihad E. Daidzic

Aviation Department Publications

This tutorial gives details on processing of raw aerodynamic data measured directly in the wind tunnel on airfoils and wings. Also procedures and equations from the lab report are given and demonstrated how to compute geometric characteristics of wings/airfoils and air data. All numeric results are typically rounded to five significant digits.

Initial Stage Of Fluid-Structure Interaction Of A Celestial Icosahedron Shaped Vacuum Lighter Than Air Vehicle, Dustin P. Graves

Theses and Dissertations

The analysis of a celestial icosahedron geometry is considered as a potential design for a Vacuum Lighter than Air Vehicle (VLTAV). The goal of the analysis is ultimately to understand the initial fluid-structure interaction of the VLTAV and the surrounding airflow. Up to this point, previous research analyzed the celestial icosahedron VLTAV in relation to withstanding a symmetric sea-level pressure applied to the membrane of the structure. This scenario simulates an internal vacuum being applied in the worst-case atmospheric environmental condition. The next step in analysis is to determine the aerodynamic effects of the geometry. The experimental setup for obtaining …

Sweep And Taper Analysis Of Surfboard Fins Using Computational Fluid Dynamics, Brandon James Baldovin

Master's Theses

The research presented here provides a basis for understanding the hydrodynamics of surfboard fin geometries. While there have been select studies on fins there has been little correlation to the shape of the fin and its corresponding hydrodynamic performance. This research analyzes how changing the planform shape of a surfboard fin effects its performance and flow field. This was done by isolating the taper and sweep distribution of a baseline geometry and varying each parameter individually whilst maintaining a constant span and surface area. The baseline surfboard fin was used as a template in Matlab to generate a set of …

A Higher-Order Method Implemented In An Unstructured Panel Code To Model Linearized Supersonic Flows, Jake Daniel Davis

Master's Theses

Since their conception in the 1960s, panel codes have remained a critical tool in the design and development of air vehicles. With continued advancement in computational technologies, today's codes are able to solve flow fields around arbitrary bodies more quickly and with higher fidelity than those that preceded them. Panel codes prove most useful during the conceptual design phase of an air vehicle, allowing engineers to iterate designs, and generate full solutions of the flow field around a vehicle in a matter of seconds to minutes instead of hours to days using traditional CFD methods. There have been relatively few …

Wake Vortex Pair Formation As An Analog For Dust Devil And Tornado Genesis, Robert L. Ash

Mechanical & Aerospace Engineering Faculty Publications

In 1966, meteorologist R.S. Scorer attempted to explain how large-scale oceanic tropical depressions become hurricanes or typhoons. His model was based on the idea that when these large-scale tropical depression structures begin to rotate, mostly due to Coriolis effects, an annular outer portion of that structure changes suddenly to a potential vortex segment, with the same outer radial limit as the low-pressure structure, but with an inner radius that conserves the overall system angular momentum and kinetic energy. By analogy with the "jump" instability describing sudden buckling of a vertical column, this paper shows that his conjecture merits additional consideration. …

Comparison Of Flow Field In The Proximity Of A Single Planar & Wrap-Around Fin, Nayhel Sharma, Palak Saini, Hrishabh Chaudhary, Gurteg Nagi, Rakesh Kumar Dr.

International Journal of Aviation, Aeronautics, and Aerospace

Abstract

This paper analyses the results of the computational analysis between a single planar and a wrap-around fin mounted on a semi-cylindrical body. A free-stream Computational Fluid Dynamics (CFD) model was simulated for both cases in the Mach 0.4-3.0M range at 0°Angle of attack, in which, the behavior of flow around the fin was investigated using a turbulence model of higher order discretization. The post-processing shows all the possible views of the flow dynamics around the fins, as well as the missile body. The aerodynamic drag and the rolling moment characteristics of the planar and the wrap-around fin have been …

Investigating The Effect Of An Upstream Spheroid On Tandem Hydrofoils, Joel Tynan Guerra

Master's Theses

This thesis documents a series of three dimensional unsteady Reynolds Averaged Navier-Stokes CFD simulations used to investigate the influence of an upstream prolate spheroid body on tandem pitching hydrofoils. The model is validated by performing separate CFD simulations on the body and pitching hydrofoils and comparing results to existing experimental data. The simulations were run for a range of Strouhal numbers (0.2-0.5) and phase differences (0-π). Results were compared to identical simulations without an upstream body to determine how the body affects thrust generation and the unsteady flow field.

The combined time-averaged thrust increases with Strouhal number, and is highest …

Bi-Stability In The Wakes Of Platooning Ahmed Bodies, Daniel M. Stalters

Master's Theses

Autonomous heavy vehicles will enable the promise of decreased energy consumption through the ability to platoon in closer formation than is currently safe or legal. It is therefore increasingly important to understand the complex and dynamic wake interactions between vehicles operating in close proximity for aerodynamic gains. In recent years, a growing body of research has documented a bi-stable, shifting wake generated behind the Ahmed reference bluff body. At the same time, studies of platooning Ahmed bodies have focused on changes to the body forces and moments at different following distances or lateral offsets, typically based around time-averaged measurements or …

Parametric Study Of Aerodynamic Performance Of An Airfoil With Active Circulation Control Using Leading Edge Embedded Cross-Flow Fan, M.A. Qayyum Mazumder

Doctoral Dissertations and Master's Theses

A concept of a cross-flow fan (CFF) embedded near the leading edge of an airfoil to actively control the boundary layer for lift and thrust enhancement has been proposed. The design places a cross-flow fan near the leading edge of an airfoil and flow is drawn in from the pressure side of the airfoil, energized and expelled out to the suction side near the leading edge. This CFF system simulates the active boundary layer control by blowing commercial computational fluid dynamics (CFD) code ANSYS Fluent is employed to perform 2-D calculations based on various parameters of the CFF and compared …

Design And Performance Estimation Of A Low-Reynolds Number Unmanned Aircraft System, Sean Lauderdale King

LSU Master's Theses

The purpose of this thesis is to conceptually design a fixed-wing unmanned aircraft systems (UAS) with a higher flight-time and top stable speed than comparable systems. The vehicle adheres to specifications derived from the client, the market, and the Federal Aviation Administration (FAA). To broadly meet these requirements, the vehicle must fly for a minimum of three hours, return to the original flight path quickly if perturbed, and must be hand-launched. The vehicle designed must also have a large potential center of gravity movement to allow for customization of the planform and client customization.

An iterative design process was used …

A Computational Fluid Dynamics Study On The Aerodynamic Performance Of Ram-Air Parachutes, Angelo A. Fonseca Pazmiño

Doctoral Dissertations and Master's Theses

The modeling of a ram-air parachute presents challenges in the prediction of the inflight geometry, as there is a strong interaction between the flow field and parachute structure. This thesis presents the development of a CAD design and CFD methodology to the simulation of ram-air parachutes in steady-state conditions. Starting from a 2D rib drawing, methods were developed to approximate the 3D geometry and efficiently model the parachute as a rigid and impermeable body. The use of distortions was implemented on a 2D, pseudo-2D, and 3D model to enhance their behavior during a real flight. The SST turbulence model was …

Validation Of Cfd Simulations For Hypersonic Flow Over A Yawed Cone, Julian Cecil

McKelvey School of Engineering Graduate Student Theses & Dissertations

This study aims to numerically simulate the wind tunnel results for hypersonic flow over a circular cone of semi-apex angle of 10 degrees yawed from 0° to 20° using the commercial computational fluid dynamics software ANSYS Fluent. The ANSYS workbench is used to create the 10° semi-apex circular cone with a shock aligned structured mesh of 3.05 million cells surrounding the cone. Simulation boundary conditions for pressure and temperature in the far field correspond to Tracy’s wind tunnel experiment at Cal Tech. The six simulations cases are conducted for yaw angles of 0, 8, 12, 16, 20 and 24 degrees. …

Aerodynamic Design And Analysis Of A Large-Scale Stall-Regulated H-Type Vertical Axis Wind Turbine For An Offshire Floating Installation, Brian Peter Hand

PhDs

Wind energy has witnessed a consistent expansion over the past decade, especially with the move to offshore installation. There is an increasing need to further exploit superior offshore wind resources, which is pushing multi-megawatt wind turbines into deeper water locations where the current popular horizontal axis wind turbine configuration is not entirely suitable. In particular, there has been a renewed interest in the vertical axis wind turbine (VAWT) configuration due to its inherent design attributes for an offshore floating application and also its potential to provide a significant reduction in the system cost of energy. However, challenges still remain as …

Design Of Shape-Conforming Nosecone For Optimal Fluid Flow From Transonic To Supersonic Range, Anna Tombazzi

Williams Honors College, Honors Research Projects

Modern flight vehicles, such as rockets, missiles, and airplanes, experience a force caused by forebody wave drag during the flight. This drag force is induced when the frontal point of each vehicle breaks the pressure wave during flight. Efforts to reduce this wave drag force to improve flight efficiency include modifying the nosecone profile of the flight vehicles to lower the drag force.

This project revolved around creating a design to make the transformation of nosecone shapes from a ¾ Parabolic profile to a ½ Power Series profile possible, mid-flight. Using a novel nosecone assembly, shape memory alloys (SMAs) and …

Aerodynamic And Performance Analysis Of A Morphing Helicopter Rotor System, Vinay Gopal Krishnan

Doctoral Dissertations and Master's Theses

The purpose of this study was to investigate the effect of rotor morphing, specifically variable rotor speed and variable blade twist, on various parameters such as the distribution of angle of attack, lift, power, thrust and/or other metrics describing the performance of a helicopter rotor. A MATLAB based blade element theory model was developed and executed for different flight conditions. The model was validated against the flight test data of a UH-60. Effects on power, lift to drag ratio and rotor drag from variations in blade twist, rotor speed, rotor radius and blade chord was analyzed. Morphing cases were applied …