Aerodynamics and Fluid Mechanics Commons^™

A Computational Fluid-Structure Interaction Method For Simulating Supersonic Parachute Inflation, Jonathan Boustani

Theses and Dissertations--Mechanical and Aerospace Engineering

Following the successful landing of the Curiosity rover on the Martian surface in 2012, NASA/JPL conducted the low-density supersonic decelerator (LDSD) missions to develop large diameter parachutes to land the increasingly heavier payloads being sent to the Martian surface. Unexpectedly, both of the tested parachutes failed far below their design loads. It became clear that there was an inability to model and predict loads that occur during supersonic parachute inflation. In this dissertation, a new computational method that was developed to provide NASA with the capability to simulate supersonic parachute inflation is presented and validated. The method considers the loose …

Wind Tunnel Data Acquisition System Development Using Labview, Riley Bishop

Mahurin Honors College Capstone Experience/Thesis Projects

Utilizing an educational-purpose wind tunnel, a data acquisition system through LabVIEW was created to experimentally analyze the aerodynamic forces experienced by objects in uniform external flow by automatically performing trials and interpreting electrical measurement signals. To verify experimental results from pressure distribution data around an object, a force balance was designed to mount objects stationarily in the wind tunnel test section while directly measuring the total lift and drag forces, calculating the pitching moment (for airfoils), and monitoring the angle of attack. The force balance design includes three load cells, one for measuring drag force and two for measuring total …

Comparative Study On The Prediction Of Aerodynamic Characteristics Of Mini - Unmanned Aerial Vehicle With Turbulence Models, Somashekar V, Immanuel Selwyn Raj A

International Journal of Aviation, Aeronautics, and Aerospace

When dealing with CFD simulations the turbulent nature is seen on most of the engineering flows and these flows need to be solved. Reliable and applicable CFD outputs can be obtained from the accurate modelling of the turbulence as it is one of the most vital elements of CFD modelling. The RANS equations are extensively employed to analyse the complex flows over aircraft and for this purpose, a turbulence model is needed for turbulent flow analyses. Compatible turbulence must be chosen for the exact predictions of aircraft aerodynamic characteristics. In this report, numerical analyses of Mini-UAV are done to compare …

Theoretical Study Of Magnetic Particles In A Shear Flow Subjected To A Uniform Magnetic Field, Christopher A. Sobecki

Doctoral Dissertations

"Magnetic manipulation of non-spherical magnetic microparticles is important for applications in shape-based and magnetic-based separations such as waste management, disease diagnostics, drug delivery, and mining. Manipulations of magnetic microparticles also include chain formation to assemble compositions for electronics, drug loading designs, and magnetorheological fluids for smart armor, hydraulic brakes, and dampers. In microfluidic devices, separation-formation-effectiveness depends on the shape of the channel, the shear rate, and the magnetic field strength and direction.

Particle separation and chain formation involved highly complex and computational expense-demanding studies in microfluidic devices, magnetic fields, and particle- particle/wall interactions. This research took complex experimental studies and …

Time Domain Boundary Element Method Prediction Of Noise Shielding By A Naca 0012 Airfoil, Douglas M. Nark, Fang Q. Hu

Mathematics & Statistics Faculty Publications

As aircraft noise constraints become more stringent and the number/mixture of aircraft configurations grows, it becomes more important to understand the interaction of individual aircraft noise sources with nearby aircraft structures. Understanding these interactions and exploring possible approaches to mitigate or exploit their acoustic impact is essential for overcoming key noise barriers. This paper describes the further validation of a time domain boundary element approach for the prediction of the interactions between incident noise sources and nearby aircraft structures. Predictions were completed for multiple source locations and comparisons of these results with measured data are presented. Overall, very good agreement …

Study Of The Mechanlsm Of Flow-Induced Vibrations Of A Cylinder In Proximity To A Wall, Jonathan M. Chambers

Master’s Theses

Flexible bluff bodies exposed to a uniform fluid flow undergo vibration due to vortex-shedding from the body. This phenomenon is known as vortex-induced vibration (VIV). Structural members, such as cables, conduits, and pipes, are susceptible to VIV. Vortex-induced vibrations result in structural stresses due to elastic structural deformation from the flow-induced loading. Cylindrical structures in proximity to planar surfaces can undergo vortex-induced vibrations when the gap between the cylinder and the planar surfaces is above a critical value. This laboratory study investigated the mechanism of vibration and planar wall proximity effect on the cylinder response to the vortex shedding process. …

Fluid-Wall Interactions In Pseudopotential Lattice Boltzmann Models, Cheng Peng, Luis F. Ayala, Orlando M. Ayala

Engineering Technology Faculty Publications

Designing proper fluid-wall interaction forces to achieve proper wetting conditions is an important area of interest in pseudopotential lattice Boltzmann models. In this paper, we propose a modified fluid-wall interaction force that applies for pseudopotential models of both single-component fluids and partially miscible multicomponent fluids, such as hydrocarbon mixtures. A reliable correlation that predicts the resulting liquid contact angle on a flat solid surface is also proposed. This correlation works well over a wide variety of pseudopotential lattice Boltzmann models and thermodynamic conditions.

Design And Testing Of A Feed-Forward Control System For Deployable Vortex Generators Dependent On Angle Of Attack, Solomon B. Whitmire, Christopher J. Chapanar, Kirklin M. Anderson, Nickalus R. Amon, Daniel W. Chech

Williams Honors College, Honors Research Projects

A vortex generator (VG hereafter) is a common feature of an aircraft wing that disturbs the flow on the leading edge of the wing, thus energizing the boundary layer and reducing flow separation. For an aircraft experiencing flow separation, VGs can increase the lift-to-drag ratio of the wing and prevent stall; however, if flow separation isn’t an issue, the unnecessary frontal area of the VGs has the potential to produce parasitic drag. This study seeks to determine whether the use of a deployment system can improve the performance of VG’s by raising or lowering them depending on the angle of …

Oblique Shock Wave Diffuser Design, Noah Riggenbach

Williams Honors College, Honors Research Projects

In this Honors Research Project, I will investigate the aerodynamic drag on certain defined ramps and cone/cylinder geometries representing oblique shock wave diffusers. The goal is to develop an oblique shock wave diffuser that decelerates supersonic air while maintaining a limited aerodynamic drag profile. The aerodynamic drag will first be obtained by calculating the pressure coefficient and the skin friction coefficient using the fluid simulation software ANSYS Fluent (version 2019). Limiting drag is important for aircraft flight performance, especially at supersonic speeds. At flight speeds above Mach 1, shock waves form and the air passing through these waves experiences a …

Road Racing Aerodynamic Simulation + Testing, Jack Sawyer

Williams Honors College, Honors Research Projects

There are multiple goals for this project. The first goal of this project is to design, assemble and simulate additional aerodynamic components. Another goal is to create a product that can analyze various angles of attack of Aerodynamic components. The product will be used on, or off the track to determine the lift coefficients of vehicles at varying speeds. I will be using my 1992 Honda Civic for testing and compare my physical results to my simulated tests.

The project did come with a list of design and manufacturing challenges along with additional finical cost which has resulted in some …

Flow Field Measurement And Qualification Of The West Virginia University Environmental Wind Tunnel, Katherine Mary Reid

Graduate Theses, Dissertations, and Problem Reports (ETD)

In 2013 West Virginia University acquired an Environmental Wind Tunnel from Cornell University. Due to the state of the tunnel, elements of the tunnel were redesigned and rebuilt at the West Virginia University Hangar in Morgantown, West Virginia. The motivation of this research was to evaluate and qualify the flow field within the test section of this redesigned and reconstructed wind tunnel. The tunnel has many uses for the university, including outside research opportunities as well as educational purposes for students in the Aerospace Engineering Department. The methods employed for this effort included developing a grid of pitot tubes to …

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 …

Numerical Investigations Of Transient Wind Shear From Passing Vehicles Near A Road Structure (Part I: Unsteady Reynolds-Averaged Navier-Stokes Simulations), Hamid Rahai, Assma Begum

Mineta Transportation Institute

In this research, the authors performed unsteady numerical simulations of a moving Ahmed body under a freeway overpass at different distances from the bridge columns in order to evaluate transient wind shear and the wind load on these columns. Results have shown that when the vehicle is at 0.75W distance from the bridge columns, an unsteady wind speed of up to 24 m/s is observed at the columns with a pressure coefficient difference of 0.9. Here W is the width of the vehicle. These results indicate with an appropriate system for harnessing these wind energy potentials, significant renewable electric power …

Microfluidics Design Considering Hyperuniformity And Cell Transport In Flow For Improved Circulating Tumor Cell Capture Efficiency, Michael Clarence Hood

Graduate Research Theses & Dissertations

Isolation of circulating tumor cells (CTCs) from patient derived blood samples for cancerdiagnostics and monitoring is challenging due to the extremely low CTC concentration. This thesis work evaluates the performance of passive microfluidics devices with different designs based on computational modeling. A new cell separation method is proposed based on velocity differentiation of varying cell sizes. All numerical studies were conducted in 2D based on a fluid structure interaction code where the fluid flow was solved based on the lattice Boltzmann method (LBM) implemented in Palabos, and the cell dynamics were simulated based on the molecular dynamics package LAMMPS, with …

Blood Flow Simulation In A Microvascular Network, Kacper Ostalowski

Graduate Research Theses & Dissertations

Cardiovascular disease such as heart attack or stroke has been the leading cause of death in the US for over 100 years. Understanding the blood cell transport physics in a vascular network is important in both fundamental research and clinical practices. In this study, 3Dnumerical simulations on blood flow in a complex retina vascular network were performed considering deformable red blood cells (RBCs), white blood cells (WBCs), and obstructed vessels. The blood was modeled as a mixture of RBCs and WBCs suspended in fluid. The fluid was solved using the lattice Boltzmann method (LBM), and blood cells were modeled by …

Dynamic Behavior And Interactions Of Ferrofluid Droplets Under Magnetic Fields In Low Reynolds Number Flows, Md Rifat Hassan

Doctoral Dissertations

Digital microfluidics in combination with emulsion microfluidics are crucial building blocks of droplet-based microfluidics, which are prevalent in a wide variety of industrial and biomedical applications, including polymer processing, food production, drug delivery, inkjet printing, and cell-based assays. Therefore, understanding the dynamics and interactions of droplets as well as the interactions between the droplets and solid surfaces are of great importance in order to improve the performance or product in these applications.

Recently, several studies in the literature have demonstrated the potential of magnetic fields in controlling the behavior of droplets in microscale; however, the fundamental mechanism behind the interesting …

A Model For Inhalation Of Infectious Aerosol Contaminants In An Aircraft Passenger Cabin, Bert A. Silich

International Journal of Aviation, Aeronautics, and Aerospace

Aerosol contamination of an aircraft cabin by infectious passengers is a concern of passengers, aircrew and the aviation industry. This may be especially important during a pandemic, such as COVID-19, where the full extent of aerosol transmission is not well understood. A statistical method to determine the number of infectious passengers on board along with a mathematical model estimating the contaminant concentration of aerosols in the cabin and the number of inhaled infectious particles by passengers is presented. An example is used to demonstrated how the results can be estimated during normal operations and emergency conditions with malfunctions of the …

Numerical Analysis Of Aerospike Engine Nozzle Performance At Various Truncation Lengths, Sam Dakka Dr, Oliver Dennison

International Journal of Aviation, Aeronautics, and Aerospace

The aerospike engine was first devised in the early 1960s where it provided new means of reaching orbit in a single stage. The paper aimes to demonstrate the viability of the technology by showcasing the increased nozzle thrust efficiency over the conventional bell nozzle. Various truncations were applied to the nozzle and each was subjected to two conditions, an over-expansion and near optimum condition. The nozzle contour was developed using the simple approximation method and was chosen to replicate that of the XRS-2200. This anchored the data, thereby validating the computational fluid dynamics (CFD) simulation. Simulations were completed for at …

Aerodynamic Performance Analysis Of Co-Flow Jet Airfoil, C M Vigneswaran, Vishnu Kumar G C

International Journal of Aviation, Aeronautics, and Aerospace

The work in this paper aims to increase the maximum lift coefficient of the airfoil by implementing the co-flow jet concept on NACA 0018 airfoil and also to investigate the performance of co-flow jet (CFJ) airfoil. To conduct numerical solution, RANS equations have been solved for 2D incompressible and unsteady flow using the Spalart-Allmaras turbulence model. The suction surface of the airfoil is modified by placing the injection slot near the leading edge and the suction slot near the trailing edge. A small mass of air is withdrawn into the airfoil suction slot, pressurized by a pumping system located inside …

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 …

Albatross And Falcon Inspired Bionic Uav: An Aerodynamic Analysis, Bilji C. Mathew, Sagar K. Sahu, Prantik Dutta, Rushi Savale, Muruga Lal Jeyan Jv Dr.

International Journal of Aviation, Aeronautics, and Aerospace

The drone industry yearns for enhanced aerodynamic performance. In order to achieve this feat, researchers and engineers are trying to mimic the natural flyers due to their aerodynamic optimality. One such flyer, the Albatross is an inspiration for many marine drones due to its planform and aerodynamic efficiency. The wing of the plan form is designed and simulated to study its properties. The Bell-Shaped Lift Distribution is incorporated for higher efficiency and elimination of the total downwash produced in case of an Elliptical Lift Distribution. A blended wing body inspired by the Falcon is used for smoother airflow interactions. Furthermore, …

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 …

Aerodynamic Characterization Of Bio-Mimicked Pleated Dragonfly Aerofoil, Md Akhtar Khan, Chinmaya Padhy

International Journal of Aviation, Aeronautics, and Aerospace

The work inspired by the dragonfly wing corrugation positioned at the front wing's radius section lying at 40% of the total wingspan of forewing from the root section. During gliding flight, dragonfly wings presumed to be an ultra-light aerofoil due to its well-defined cross-sectional corrugation. The aerodynamic simulation carried out to understand the aerodynamic performance of a bio-mimetic dragonfly corrugated airfoil at low Reynolds number range of 75000-150000 to explore the potential advantages of pleated airfoils at a varying angle of attack from 0° to 12°. CFD analysis accomplished by using ANSYS Fluent to understand the aerodynamic performance of the …

Nebulizer-Based Systems To Improve Pharmaceutical Aerosol Delivery To The Lungs, Benjamin M. Spence

Theses and Dissertations

Combining vibrating mesh nebulizers with additional new technologies leads to substantial improvements in pharmaceutical aerosol delivery to the lungs across therapeutic administration methods. In this dissertation, streamlined components, aerosol administration synchronization, and/or Excipient Enhanced Growth (EEG) technologies were utilized to develop and test several novel devices and aerosol delivery systems. The first focus of this work was to improve the poor delivery efficiency, e.g., 3.6% of nominal dose (Dugernier et al. 2017), of aerosolized medication administration to adult human subjects concurrent with high flow nasal cannula (HFNC) therapy, a form of continuous-flow non-invasive ventilation (NIV). The developed Low-Volume Mixer-Heater (LVMH) …

Dances And Escape Of The Vortex Quartet, Brandon Behring

Dissertations

This dissertation considers the linear stability of a one-parameter family of periodic solutions of the four-vortex problem known as 'leapfrogging' orbits. These solutions, which consist of two pairs of identical yet oppositely-signed vortices, were known to W. Gröbli (1877) and A. E. H. Love (1883) and can be parameterized by a dimensionless parameter related to the geometry of the initial configuration. Simulations by Acheson and numerical Floquet analysis by Tophøj and Aref both indicate, to many digits, that the bifurcation occurs at a value related to the inverse square of the golen ratio. Acheson observed that, after an initial period …

Design And Control Techniques Of The Open-Circuit Subsonic Wind Tunnel With Closed Testing Section, Jamshid Yakhshilikov, Jamshid Inoyatkhodjaev

Acta of Turin Polytechnic University in Tashkent

This paper will describe the design and control techniques of the open-circuit subsonic wind tunnel with closed testing section (WT) for study purpose. The goal is to design a WT that can be tested at a wind speed of 30 m/s, where the desired cross-sectional area of the test chamber is 0.5x0.5 m. The pressure drop inside the WT has been calculated in order to select one of the available axial fans from the manufacturer’s catalog, and computational fluid dynamics (CFD) was performed to check the result. In order to obtain a smooth airflow in the test section, a proportional …

Entrainment Processes For A Jet In Cross-Flow: The Quantification Of Turbulent Contributions And Their Importance On Accurate Modeling, Graham Asher Freedland

Dissertations and Theses

A jet in cross flow (JICF) is examined experimentally by injecting a stream of air into crossing fluid with an aim into quantifying entrainment process and downstream evolution. The behavior of JICF is important to fields ranging from turbine-blade cooling to smokestack pollution and volcanic eruption dynamics. Existing simplified volcanic plume models are tested; most importantly, the near-field contributions of complex interconnected vortex systems, which present significant uncertainties because they assume negligible turbulence. While jets in irrotational cross-flow have been investigated, this analysis has focused on the interaction between a turbulent jet in low and highly turbulent cross-flow created by …

The Varied Thermal Response Of Magnetic Iron-Oxide Nanoparticles During Induction Heating In Liquid And Solid-Liquid Phase Change Mediums, Joshua Tompkins

Graduate Theses and Dissertations

This study investigates the induction heating response of uncapped iron oxide nanoparticles sonically dispersed as a nanofluid and mechanically distributed in solid phase change materials. The nanoparticles examined have a mean diameter of 14.42 nm and are magnetically heated in an alternating magnetic field at an amplitude of 72.6 kA/m at frequencies of 217, 303, and 397 kHz. Nanoparticle characterization was undertaken through transition electron microscopy, x-ray diffraction, and dynamic light scattering when in suspension. Carrier fluids were characterized through viscosity, heat capacity, and density measurements which were used in the calorimetric calculation of the specific absorption rate (SAR) of …

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 Multi-Functional Surface Acoustic Wave Sensor, Xin Xu

Doctoral Dissertations and Master's Theses

A surface acoustic wave (SAW) sensor can have broad industrial applications due to its compact size, low cost-effectiveness, and versatility of sensible measurands, as well as the wireless capabilities. In this study, a theoretical modeling approach accompanied by a MATLAB-based algorithm of the SAW device is first presented. With the designed dimensional parameters and selected material properties, numerical analyses are performed using COMSOL Multiphysics to validate the theoretical results. Various postprocessing responses of the propagated SAWs in both time and frequency domains, such as time delay, insertion loss, and frequency shift, are examined to evaluate the device performances. Also, the …