Aerodynamics and Fluid Mechanics Commons^™

Structural Dynamics Of Awt-27 Wind Turbine Blade, Amr Ismaiel

Future Engineering Journal

Wind energy is one of the world’s current leading renewable energy resources. One of the major aspects of studying wind turbines is the structural dynamics for the turbine structure including blades and support structure. In the current work, the blades of the Advanced Wind Turbine (AWT-27) are investigated in a dynamic approach. Different wind fields have been generated for the study to provide different Design Load Conditions (DLCs). Three laminar wind velocities of 5 m/s, 12 m/s, and 17 m/s were simulated. Turbulent wind flow fields have also been generated at the three standard classes A, B and C of …

Carbon Nanotube-Based Microscale Capacitive Flow Sensors, Nathaniel Holmes

Electronic Thesis and Dissertation Repository

Micro-scale flow sensors present several advantages over traditional flow sensing
methods, including minimal flow disruption, high spatial resolution, and low unit
cost. Many existing micro-scale thermal and piezo flow sensors struggle with temperature drift and require complicated fabrication processes. This thesis details
the development of a 60 μm by 60 μm by 50 μm drag-based capacitive flow sensor
constructed from vertically aligned carbon nanotube forests. The construction
of a thermal chemical vapour deposition system for sensor synthesis is also de-
tailed. Manual manipulation of the sensor with an atomic force microscope probe
was found to produce a full scale signal …

Effectiveness Of Air Pollution Mitigation Systems: Transport, Transformation, And Control Of Ozone In The Indoor Environment, Pradeep Ramasubramanian

Dissertations and Theses

Buildings are critical environments governing our collective exposure to air pollution and energy consumption. While there exist concerns regarding increases in building energy consumption due to indoor air interventions, improvements to the quality of air indoors can improve health, comfort, and productivity. Air cleaning technologies that can improve indoor air quality with minimal energy consumption have become ever more important. These technologies are utilized at various scales; from passive removal of pollutants in the air entering the indoor environment to active cleaning of air within the breathing zone. To better understand the effectiveness of active and passive ozone mitigation technologies …

A Three-Dimensional, Analytical Wind Turbine Wake Model: Flow Acceleration, Empirical Correlations, And Continuity, Zein Ahmad Sadek

Dissertations and Theses

A new, three-dimensional, analytical, steady state wake model is presented which includes local flow acceleration near the rotor improving wake description compared to existing models. Wake structures such as the momentum deficit and regions of accelerated flow are concisely described with compound and normal Gaussian functions. Large-eddy simulations (LES) are used as training data to develop the model using two, inline turbines under various inflow conditions parameterized by hub height wind speed and turbulence intensity. Mass conservation is considered by fixing two components of the wake velocity model and optimizing the third to best satisfy continuity; after which, the model …

Structural Loads And Preliminary Structural Design For A World Speed Record-Breaking Turbo-Prop Racing Airplane, Matthew G. Slymen

Master's Theses

The Cal Poly SLO Turbo-Prop Racer project aims to design a world speed record-breaking aircraft, capable of flying more than 550 miles per hour on a 3-kilometer closed course. To further this endeavor, this thesis presents the calculations of load distributions across the aircraft’s wing and tail and preliminary structural estimates of primary structural components for verification of the loads calculations and for use in a future finite element model. The aircraft’s fundamental design characteristics effect on the structure of the aircraft, namely the unique Y-tail design, are first examined. Then, loads are calculated in accordance with the regulation dictated …

Channeling Influence On Noise And Aerodynamic Performance Of Naca 0012 Airfoil As A Possible Solution Of Wind Turbines Noise, Hussein Khudhayer Mohammad

Dissertations

This work numerically and experimentally investigates the effect of using channels inside airfoils on the noise level as a possible resolution for aerodynamic noise generated by wind turbines. The work also investigates aerodynamic performance and turbulence around the employed airfoils. The results reveal that some of the samples show some improvement in reducing the aerodynamic noise. The reduction of the aerodynamic noise is explained as the trailing edge blowing injection that reduces the wake momentum deficit of the blade and reduces the pressure fluctuation which is responsible for noise production. Particularly, the angles of channel inclination with respect to the …

Aerodynamics And Turbulent Wake-Flow Characteristics Of Owls During Flapping Flight, Krishnamoorthy Krishnan

Electronic Theses and Dissertations

Owls exhibit unique flight capabilities in the low Reynolds number flow regime which is prone to complex viscous flow phenomena. They possess unique feather features and flexible wing structures which are postulated to help them fly nearly silently and stably at low speeds in a complex flow setting. Understanding the aerodynamics of owls could pave the way to enhance the future designs of small flying vehicles. Though it has been a focus of research over multiple decades, no conclusive agreement has been attained on the aerodynamic mechanisms associated with owl flight. Particularly, the aerodynamics of flapping owl flight is severely …

Flow And Heat Transfer In Swirl Tubes — A Review, Florian Seibold, Phillip M. Ligrani, Bernhard Weigand

PRC-Affiliated Research

The development of modern gas turbines for aircraft propulsion and power generation demands ever-increasing efficiency, which can be achieved by rising the turbine inlet temperature. Therefore, turbine components and especially the leading edge of turbine blades are exposed to particular high thermal loads with temperatures that are well above the melting point of the material. As a result, efficient cooling techniques are essential. Swirling flows in cyclone cooling systems are a promising technique for internal turbine blade leading edge cooling since they promise high heat transfer rates in combination with relatively uniform heat transfer distributions. The current paper presents a …

Optical Microresonator-Based Flow-Speed Sensor, Elie Ramon Salameh

Mechanical Engineering Research Theses and Dissertations

Optical sensors have become more prominent in atmospheric measurement systems, with LiDAR instruments deployed on a variety of earth-bound, air-borne, and space-based platforms. In recent years, the interest in the human exploration of Mars has created a substantial push towards reliable and compact sensing elements for Mars exploration missions, particularly during a spacecraft’s entry, descent, and landing stages. Real-time sensors able to reliably measure the craft’s speed relative to the surrounding atmosphere during these stages are thus of great interest. In this dissertation, a proof-of-concept for an optical microfabricated sensor, which leverages the whispering-gallery-mode (WGM) and Doppler shift principles, is …

Direct Simulation And Reduced-Order Modeling Of Premixed Flame Response To Acoustic Modulation, Zheng Qiao

Theses and Dissertations

This dissertation introduces a general, predictive and cost-efficient reduced-order modeling (ROM) technique for characterization of flame response under acoustic modulation. The model is built upon the kinematic flame model–G-equation to describe the flame topology and dynamics, and the novelties of the ROM lie in i) a procedure to create the compatible base flow that can reproduce the correct flame geometry and ii) the use of a physically-consistent acoustic modulation field for the characterization of flame response. This ROM addresses the significant limitations of the classical kinematic model, which is only applicable to simple flame configurations and relies on ad-hoc models …

Application Of The Formal Design Of Experiments To Deformed Airfoil Testing, Alex Ligman

Honors Theses

Traditionally, one factor at a time (OFAT) testing is used to accomplish wind tunnel
experimentation. OFAT testing is a process whereby one of the defined factors in the experiment is changed while all of the other factors are held constant. Afterwards, a new factor is chosen as the one to be manipulated, and the process is then repeated until all factors have been run through. Due to the possible cost-intensive and time-consuming nature of wind tunnel testing, formal design of experiments (DOE) has begun to be applied to wind tunnel experiments. In doing so, unique analyses can be made that …

Development And Testing Of A 1:70 Scale Model Wind Turbine Of The Iea Reference 15 Mw Floating Offshore System, Amber Parker

Electronic Theses and Dissertations

This thesis presents the development of a 1/70th scale performance-matched wind turbine intended for wind and wave basin model testing of commercially viable floating wind turbine structures based off of the International Energy Agency (IEA) Wind 15 MW design. The focus of this demonstration is to test active blade pitch response controls and to provide an experimental dataset for use by modelers and industry for future turbine improvements. Future research is planned to test the turbine in conjunction with an actively damping hull to test the interactions between the two control systems.

Outlined in this thesis are the methods of …

Experimental Investigation Of Supersonic Jets Using Optical Diagnostics, Theron James Price

Doctoral Dissertations

The complexity of many fluid flows and phenomena is a well-known characteristic driven primarily by turbulence, which has been a focal point of study for decades. Most engineering applications in fluids will encounter turbulence, and hence the need to understand how turbulence might influence the problem at hand is omnipresent. In many turbulent flows, there are large-scale coherent structures which directly influence macro-scale processes of engineering relevance, such as noise production. Over decades of study, it has been demonstrated that similar structures are often observed across many flowfields, despite differences in characteristic parameters, and this has led to the pursuit …

A Study Of Asymmetric Supersonic Wind Tunnel Nozzle Design, Brittany A. Davis

Mechanical & Aerospace Engineering Theses & Dissertations

Achieving higher Mach numbers for private and commercial flight is a growing interest in the aerospace community. To qualify vehicles prior to flight, tests must be run in wind tunnels. Asymmetric wind tunnel nozzles are of continuing interest to the aerospace community due to their ability to change throat geometry, allowing for a range of Mach numbers to be achieved that encompasses all of the supersonic regime. The sliding block wind tunnel at Old Dominion University (ODU) is designed for a range of Mach numbers from about 1.8 to 3.5 but is limited to an upper limit of 2.8 by …

Development Of A Bio-Inspired Artificial Butterfly Vehicle, Thomas Payne Clark

Honors Capstone Projects and Theses

No abstract provided.

Effects Of Vortex Generator Placement On A Horizontal Axis Wind Turbine Blade, Dagan Sorensen

ONU Student Research Colloquium

Vortex generators are commonly used devices to control the flow over an airfoil or other surface. In this paper the effect of differing placements of vortex generators on a wind turbine airfoil, compared to an airfoil without vortex generators, were simulated using computational fluid dynamics(CFD). It was shown that, in some instances, the application of vortex generators effectively controlled the flow over the airfoil to increase the power produced by the wind turbine. According to the CFD results, the application of vortex generators at an angle increased the lift produced, as well as delaying the separation of the boundary layer.

Computational Analysis Of The Effects Of Scarfed Nozzle Variations On Jet Plumes, Andrew J. La Sorsa

ONU Student Research Colloquium

A computational fluid dynamics analysis investigating the variation of effects on nozzles with non-orthogonal exit planes, known as scarfing, was performed. The steady Reynolds-averaged Navier-Stokes model, coupled with the Spalart-Allmaras turbulence model, was used to simulate and compare plume development and characteristics using various scarfing geometries at variable inlet conditions. The jet plume cross-section is significantly affected for overexpanded conditions, while retaining the nozzle exit shape for underexpanded conditions, although slight peaks (bifurcation) do occur at the centerline. The same observations occur when slightly changing the angle of scarf. However, inverting the overall geometry of the diverging portion of the …

Computational Comparison Of Dual Bell, Expansion-Deflection, And Aerospike Nozzles, Manuel R. Abadie Ardon

Honors College Theses

In the search for a Single-Stage-to-Orbit rocket, Altitude Compensating Nozzles concepts (ACNs) have been proposed since the 1950s, but research has stalled despite the modern analysis tools available. These nozzle concepts offer optimum performance at two or more altitude settings. This research chose three of these concepts, these being the Dual Bell, Expansion-Deflection, and Aerospike, which were designed and analyzed at various pressure ratios (NPR=10,15,30,36,30,45) using Computational Fluid Dynamics (CFD) software FLUENT. Simulations generated pressure distributions along the nozzle wall, which allowed to calculate data values such as thrust coefficients. Nozzle efficiency is calculated from this data and used to …

Time-Resolved Piv Measurements Of Ship Airwakes With Quartering Winds, Kaijus H. Palm

Doctoral Dissertations and Master's Theses

The unsteady, three-dimensional, turbulent airwake over the Simple Frigate Ship No. 2 (SFS2) with quartering wind flow directions was studied in a low-speed wind tunnel facility. Surface oil flow visualization and time-resolved stereoscopic and planar particle image velocimetry (PIV) measurements were made for three crosswise planes and a single centerline streamwise plane. Measurements included various configurations with the bow of the ship model at two different quartering wind conditions of 10 and 20 degrees, as well as cases with and without the effects of a simulated atmospheric boundary layer (ABL). A comparative analysis of the time-averaged flow structures between the …

Influence Of Wing Planform Shape On The Effectiveness Of A Fixed-Slot, Yuan Zhao

Doctoral Dissertations and Master's Theses

This thesis report explores the effect of the Clark-Y wing geometry on lift and drag to use as a reference during aircraft design stage. The different characteristics investigated are fixed slot span, taper ratio, washout, and sweep angle. Plain wings, half slotted wings, and fully slotted wings were built in CATIA with an aspect ratio of 6 and different taper ratio, washout, and sweep angles. Using the CATIA models to generate the 3-D grids in Pointwise. All the simulations were tested in Ansys-Fluent under sea-level conditions with a Reynold number of 609000. The relationships between the aerodynamic characteristics and the …