Aerodynamics and Fluid Mechanics Commons^™

Identify Aerodynamic Derivatives Of The Airplane Attitude Channel Using A Spiking Neural Network, Nguyen Quang Vinh, Nguyen Duc Thanh, Hoang Minh Dac, Truong Dang Khoa

International Journal of Aviation, Aeronautics, and Aerospace

The paper proposes a method for identifying aerodynamic coefficient derivatives of aircraft attitude channel using spiking neural network (SNN) and Gauss-Newton algorithm based on data obtained from actual flights. Using SNN combination with Gauss-Newton iterative calculation algorithm allows the identification of aerodynamic coefficient derivatives in a nonlinear model for aerodynamic parameters with higher accuracy and faster calculation time. The paper proposes an algorithm to train the SNN multi-layer network by Normalized Spiking Error Back Propagation (NSEBP), in which, in the forward propagation period, the time of output spikes is calculating by solving quadratic equations instead of detection by traditional methods. …

Performance Characteristics Design Of Pulsed Plasma Thrusters For Drag Counter-Reacting, Dr. Sam Dakka

International Journal of Aviation, Aeronautics, and Aerospace

Determining the performance characteristics of off the shelf pulsed plasma thrusters to enhance the life time of low earth orbiting platforms was investigated theoretically. Pulsed plasma thruster analysis was accomplished through development of correlations from historical data that distinguished between breech fed propellant to side fed propellant designs. Based on semi-empirical equations the power required by the thruster to counter react the drag was estimated and mapped for 1U to 27U CubeSat configurations for altitude ranging between 200km to 600km. It appears that the power required is dependent on the feeding delivery system design. For side fed designs the power …

The Detrimental Effect Of Rainfall On Performance And Stability Characteristics Of Aircrafts-A Comprehensive Review, Praneeth Hr Mr, Amit Kumar Thakur Dr

International Journal of Aviation, Aeronautics, and Aerospace

The rapidly growing global market demands faster transit of human beings and goods even in unfavorable weather conditions of rainfall. The paper gives an overview of rain research methodologies, mathematical models to track raindrops in the flow field. The paper depicts the havoc rainfall causes on performance characteristics for various phases of flight in terms of evaluation of C_L and C_D and dynamic performance parameters such as short period mode. The knowledge obtained by this review paper could help designers to modify the design of aircraft such that it has better performance, stability, and control characteristics for all …

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, …

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.

Effect Of Turbulence Model Closure Coefficient Uncertainty On Scramjet Flow Field Analysis, Martin Albert Di Stefano

Doctoral Dissertations

“The numerical modeling of supersonic combustion ramjet (scramjet) engine flow paths plays an important role in the design of hypersonic air-breathing propulsion systems. Due to the complexity of the flow field physics and limited experimental data, numerical models possess uncertainties which should be addressed to improve the prediction accuracy of the simulations. In this study, the effect of turbulence model closure coefficient uncertainty on the Reynolds-averaged Navier-Stokes solution of a scramjet isolator and scramjet strut fuel injector flow field is investigated with an uncertainty quantification and sensitivity analysis study for commonly used turbulence models. Turbulence models considered in this work …

Magnetic Control Of Transport Of Particles And Droplets In Low Reynolds Number Shear Flows, Jie Zhang

Doctoral Dissertations

“Magnetic particles and droplets have been used in a wide range applications including biomedicine, biological analysis and chemical reaction. The manipulation of magnetic microparticles or microdroplets in microscale fluid environments is one of the most critical processes in the systems and platforms based on microfluidic technology. The conventional methods are based on magnetic forces to manipulate magnetic particles or droplets in a viscous fluid.

In contrast to conventional magnetic separation method, several recent experimental and theoretical studies have demonstrated a different way to manipulate magnetic non-spherical particles by using a uniform magnetic field in the microchannel. However, the fundamental mechanism …

Comparison Of Reynolds-Averaged Navier-Stokes Turbulence Models For Simulating Boundary Layers In Hypersonic Flows, Jorge-Valentino Kurose Bretzke

Masters Theses

“This study describes the use of Computational Fluid Dynamics (CFD) codes to simulate hypersonic boundary layers using several different turbulent closure models and comparing Reynolds-Averaged Navier-Stokes (RANS) simulations against Direct Numerical Simulations (DNS) of similar test cases. The test cases in this study consist of a flat plate in a Mach 8 freestream with a zero pressure gradient and wall recovery ratio of 0.48, as well as a Mach 8 axisymmetric nozzle also with a cold wall. The RANS models used in this study are the Spalart-Allmaras model, Baldwin-Lomax model, Menter K-Omega Baseline and Menter K-Omega Shear Stress Transport models. …

Characterizing Premixed Syngas Combustion In Micro-Channels, Sunita Pokharel

Graduate Theses, Dissertations, and Problem Reports (ETD)

Increasing demands in the next-generation portable power-generation devices such as unmanned aerial vehicles (UAV), microsatellite thrusters, micro-chemical reactors and sensors calls for fuels with high specific energy and low emissions to meet the current demand of green energy. Fuel-lean synthesis gas (syngas) meets both these requirements exhibiting a promising route to a clean and green environment. Thus, it is of critical importance to characterize syngas combustion and understand its properties in the micro-combustion industry. In addition to complicated flame dynamics in microscale systems, varying the syngas-fuel mixture composition as well as the boundary conditions and geometry of a combustor significantly …

Low-Cost Skewed Redundant Imu Configuration For State-Space Recovery In A Saturated Environment, Levi S. Hubbard

Graduate Theses, Dissertations, and Problem Reports (ETD)

Low-cost sensors for state space determination can be used successfully for ground vehicles, robots, unmanned aerial vehicles, and Internet-of-Things applications. When a high fidelity Inertial Measurement Unit (IMU) cannot be obtained for state space determination, low-cost sensors can be used to satisfactory standards, despite their limitations in capabilities, by using various implementation techniques. The research group was experimentally investigating state space information of an unstable flying vehicle for motion simulation validation. The high fidelity motion capture system would intermittently lose track of the flight vehicle which lost critical flight data.

The goal was to determine the potential of low-cost off-the-shelf …

Aeroelasticity Of Composite Plate Wings Using Hsdt And Higher-Order Fem, Justin A. Haught

Graduate Theses, Dissertations, and Problem Reports (ETD)

The aeroelasticity of composite wings is becoming an increasingly researched topic in aircraft design, as designers continue to replace aluminum alloy components with those made of composite materials because of their favorable strength-to-weight ratio, fatigue characteristics, and corrosion resistance. Additionally, the bending-torsion coupling exhibited by composite laminates readily allow for the aeroelastic optimization of an aerodynamic structure through the process of aeroelastic tailoring. Wings made of composites materials, however, are more vulnerable to shear deformation.

The objective of the present research is to study the divergence and flutter characteristics of composite plate wings using a higher-order shear deformation theory (HSDT) …

An Experimental And Numerical Study Of High Temperature Gaseous Flow Through An Open Cell Silicon Carbide Foam Heater, Denis Pansolin

LSU New Orleans Theses and Dissertations

No abstract provided.

Bubble Pinch-Off In Turbulence, Daniel J. Ruth, Wouter Mostert, Stephane Perrard, Luc Deike

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Although bubble pinch-off is an archetype of a dynamical system evolving toward a singularity, it has always been described in idealized theoretical and experimental conditions. Here, we consider bubble pinch-off in a turbulent flow representative of natural conditions in the presence of strong and random perturbations, combining laboratory experiments, numerical simulations, and theoretical modeling. We show that the turbulence sets the initial conditions for pinch-off, namely the initial bubble shape and flow field, but after the pinch-off starts, the turbulent time at the neck scale becomes much slower than the pinching dynamics: The turbulence freezes. We show that the average …

Performance Modeling Of Supercritical Carbon Dioxide Zigzag-Channel Printed Circuit Heat Exchangers, Katrine Birgitte Bennett

UNLV Theses, Dissertations, Professional Papers, and Capstones

Supercritical carbon dioxide (sCO2) is currently being studied as the working fluid in power producing Brayton cycles due to its excellent physical and thermodynamic properties, especially near the critical point. Printed circuit heat exchangers (PCHEs) are being considered for use as condensers and recuperators for this purpose due to their high strength and compact designs. Many experimental and numerical studies are being conducted to characterize and optimize sCO2 PCHE operation and develop correlations to describe their thermal-hydraulic performance. Additionally, a few experimental and numerical structural assessments of these PCHEs have been conducted, but all have been somewhat limited due to …

Analysis Of Shock Wave Unsteadiness Using Space And Time Correlations Applied To Shadowgraph Flow Visualization Data, Shannon Marko, Phillip M. Ligrani

PRC-Affiliated Research

Unsteady flow characteristics of a normal shock wave, a lambda foot, and a separated turbulent boundary layer are investigated within a unique test section with supersonic inlet flow. The supersonic wind tunnel facility, containing this test section, provides a Mach number of approximately 1.54 at the test section entrance. Digitized shadowgraph flow visualization data are employed to visualize shock wave structure within the test section. These data are analyzed to determine shock wave unsteadiness characteristics, including grayscale spectral energy variations with frequency, as well as time and space correlations, which give coherence and time lag properties associated with perturbations associated …

Analysis Of Shock Wave Unsteadiness Using Space And Time Correlations Applied To Shadowgraph Flow Visualization Data, Shannon Marko, Phillip M. Ligrani

PRC-Affiliated Research

Unsteady flow characteristics of a normal shock wave, a lambda foot, and a separated turbulent boundary layer are investigated within a unique test section with supersonic inlet flow. The supersonic wind tunnel facility, containing this test section, provides a Mach number of approximately 1.54 at the test section entrance. Digitized shadowgraph flow visualization data are employed to visualize shock wave structure within the test section. These data are analyzed to determine shock wave unsteadiness characteristics, including grayscale spectral energy variations with frequency, as well as time and space correlations, which give coherence and time lag properties associated with perturbations associated …

Analysis Of Shock Wave Unsteadiness Using Space And Time Correlations Applied To Shadowgraph Flow Visualization Data, Shannon Marko, Phillip M. Ligrani

PRC-Affiliated Research

Unsteady flow characteristics of a normal shock wave, a lambda foot, and a separated turbulent boundary layer are investigated within a unique test section with supersonic inlet flow. The supersonic wind tunnel facility, containing this test section, provides a Mach number of approximately 1.54 at the test section entrance. Digitized shadowgraph flow visualization data are employed to visualize shock wave structure within the test section. These data are analyzed to determine shock wave unsteadiness characteristics, including grayscale spectral energy variations with frequency, as well as time and space correlations, which give coherence and time lag properties associated with perturbations associated …

Methodology Of Topology Optimization, Naziha Khandoker

Honors Theses

The need for lighter products is becoming increasingly essential as it cuts material cost and significant amount of weight, which is a key factor in the automotive and aerospace industries. Topology optimization allows us to achieve that by applying the concept to different structures with the goal of optimal distribution of material within finite volume design domain. Its algorithms selectively remove and relocate elements to achieve the optimum performance. This project performs a study on the effect of each design parameter over mechanical performance using Finite Element Analysis and applies it to set of wing attachment brackets. The optimized brackets …

Dynamic Pressure Sensing For The Flight Test Data System, Marc Y. Goupil

Master's Theses

This thesis describes the design, assembly, and test of the FTDS-K, a new device in the Boundary Layer Data System (BLDS) family of flight data acquisition systems. The FTDS-K provides high-frequency, high-gain data acquisition capability for up to two pressure sensors and an additional three low-frequency pressure sensors. Development of the FTDS-K was separated into a core module, specialized analog subsystem, and practical testing of the FTDS-K in a flow measurement mission. The core module combines an nRF52840-based microcontroller module, switching regulator, microSD card, real-time clock, temperature sensor, and trio of pressure sensors to provide the same capabilities as previous-generation …