Aerospace Engineering Commons^™

Merrill-Cazier Library Gas Exhibition, Betty Rozum, Andrew Wesolek, Pamela N. Martin

Andrew Wesolek

This exhibition, presented in the Merrill-Cazier Library, captured the history and accomplishments of the GAS program. Click the download button to see a PowerPoint presentation featuring images and text from the exhibition.

Isogeometric Fluid–Structure Interaction Analysis With Emphasis On Non-Matching Discretizations, And With Application To Wind Turbines, Y. Bazilevs, Ming-Chen Hsu, M. A. Scott

Ming-Chen Hsu

In this paper we develop a framework for fluid–structure interaction (FSI) modeling and simulation with emphasis on isogeometric analysis (IGA) and non-matching fluid–structure interface discretizations. We take the augmented Lagrangian approach to FSI as a point of departure. Here the Lagrange multiplier field is defined on the fluid–structure interface and is responsible for coupling of the two subsystems. Thus the FSI formulation does not rely on the continuity of the underlying function spaces across the fluid–structure interface in order to produce the correct coupling conditions between the fluid and structural subdomains. However, in deriving the final FSI formulation the interface …

Stochastic Optimal Control In Nonlinear Systems, Celestin Nkundineza

Celestin Nkundineza

Stochastic control is an important area of research in engineering systems that undergo disturbances. Controlling individual states in such systems is critical. The present investigation is concerned with the application of the stochastic optimal control strategy developed by To (2010) and its implementation as well as providing computed results of linear and nonlinear systems under stationary and nonstationary random excitations. In the strategy the feedback matrix is designed based on the achievement of the objectives for individual states in the system through the application of the Lyapunov equation for the system. Each diagonal element in the gain or associated gain …

Structural Damage Assessment Of Propulsions System Components By Impedance Based Health Monitoring, Richard Martin, Andrew Gyekneyesi, Jerzy Sawicki, George Baaklini

Jerzy T. Sawicki

No abstract provided.

High Temperature Fusion Reactor Cooling Using Brayton Cycle Based Partial Energy Conversion, Albert Juhasz, Jerzy Sawicki

Jerzy T. Sawicki

For some future space power systems using high temperature nuclear heat sources most of the output energy will be used in other than electrical form, and only a fraction of the total thermal energy generated will need to be converted to electrical work. The paper describes the conceptual design of such a “partial energy conversion” system, consisting of a high temperature fusion reactor operating in series with a high temperature radiator and in parallel with dual closed cycle gas turbine (CCGT) power systems, also referred to as closed Brayton cycle (CBC) systems, which are supplied with a fraction of the …

Review Of The Challenger Launch Decision: Risky Technology, Culture And Deviance At Nasa, Peter F. Meiksins

Peter Meiksins

Reviews the book "The Challenger Launch Decision: Risky Technology, Culture and Deviance at NASA," by Diane Vaughan.

Modeling Disk Cracks In Rotors By Utilizing Speed Dependent Eccentricity, Andrew L. Gyekenyesi, Jerzy T. Sawicki, Wayne C. Haase

Jerzy T. Sawicki

This paper discusses the feasibility of vibration-based structural health monitoring for detecting disk cracks in rotor systems. The approach of interest assumes that a crack located on a rotating disk causes a minute change in the system’s center of mass due to the centrifugal force induced opening of the crack. The center of mass shift is expected to reveal itself in the vibration vector (i.e., whirl response; plotted as amplitude and phase versus speed) gathered during a spin-up and/or spin-down test. Here, analysis is accomplished by modeling a Jeffcott rotor that is characterized by analytical, numerical, and experimental data. The …

Wind Turbine Aerodynamics Using Ale–Vms: Validation And The Role Of Weakly Enforced Boundary Conditions, Ming-Chen Hsu, Ido Akkerman, Yuri Bazilevs

Ming-Chen Hsu

In this article we present a validation study involving the full-scale NREL Phase VI two-bladed wind turbine rotor. The ALE–VMS formulation of aerodynamics, based on the Navier–Stokes equations of incompressible flows, is employed in conjunction with weakly enforced essential boundary conditions. We find that the ALE–VMS formulation using linear tetrahedral finite elements is able to reproduce experimental data for the aerodynamic (low-speed shaft) torque and cross-section pressure distribution of the NREL Phase VI rotor. We also find that weak enforcement of essential boundary conditions is critical for obtaining accurate aerodynamics results on relatively coarse boundary layer meshes. The proposed numerical …

Fundamental Sizing Implications Of Constant Or Increasing Weight Aircraft, Robert A. Mcdonald

Robert A. McDonald

As the energy storage capabilities of batteries and fuel cells advance, these technologies are increasingly being considered for aircraft primary propulsion. In addition to other fundamental differences from conventional systems, these concepts may have constant or even increasing mass throughout the mission. In this paper, the implications of constant or increasing mass on aircraft sizing are considered with the aim of generating insight for the design of these systems.

Ale-Vms And St-Vms Methods For Computer Modeling Of Wind-Turbine Rotor Aerodynamics And Fluid–Structure Interaction, Yuri Bazilevs, Ming-Chen Hsu, Kenji Takizawa, Tayfun E. Tezduyar

Ming-Chen Hsu

We provide an overview of the Arbitrary Lagrangian–Eulerian Variational Multiscale (ALE-VMS) and Space–Time Variational Multiscale (ST-VMS) methods we have developed for computer modeling of wind-turbine rotor aerodynamics and fluid–structure interaction (FSI). The related techniques described include weak enforcement of the essential boundary conditions, Kirchhoff–Love shell modeling of the rotor-blade structure, NURBS-based isogeometric analysis, and full FSI coupling. We present results from application of these methods to computer modeling of NREL 5MW and NREL Phase VI wind-turbine rotors at full scale, including comparison with experimental data.

The North Dakota Space Robotics Program: Teaching Spacecraft Development Skills To Students Statewide With High Altitude Ballooning, Jeremy Straub, Ronald Fevig

Jeremy Straub

The University of North Dakota is serving as the lead institution in a statewide effort to develop student spacecraft engineering skills. This effort, which is part of the North Dakota Space Robotics Program (NDSRP), provides students the ability to participate in the design, development and fabrication of a small satellite analog that is launched by a high altitude balloon. The first iteration of the NDSRP Near-Spacecraft Project is generating a functional prototype of a remote sensing payload, which will perform onboard image processing. This project included undergraduate and graduate students from two institutions and five different academic departments. The students …

Formalizing Mission Analysis And Design Techniques For High Altitude Ballooning, Jeremy Straub, Ronald Fevig

Jeremy Straub

High altitude balloon (HAB) missions can be and are used to teach concepts related to spacecraft and satellite design. A HAB mission, however, presents unique characteristics, which must be understood and respected to produce a desirable outcome. Because of this, flying an unaltered satellite design as a HAB payload would be as undesirable as utilizing an unaltered HAB design as a satellite. A well-defined process for HAB mission design is thus needed. The process presented mirrors commonly used space mission design processes to facilitate easy transition between the two. It is also comparatively simple, due to the smaller scale of …

Multi-Tier Exploration Concept Demonstration Mission, Jeremy Straub

Jeremy Straub

A multi-tier, multi-craft mission architecture has been proposed but, despite its apparent promise, limited use and testing of the architecture has been conducted. This paper proposes and details a mission concept and its implementation for testing this architecture in the terrestrial environment. It is expected that this testing will allow significant refinement of the proposed architecture as well as providing data on its suitability for use in both terrestrial and extra-terrestrial applications. Logistical and technical challenges with this testing are discussed.

Cubesats: A Low-Cost, Very High-Return Space Technology, Jeremy Straub

Jeremy Straub

No abstract provided.

Experimental Evaluation Of Turbine Blade With Potassium Evaporative Cooling, Jessica Townsend

Jessica Townsend

A new method of turbine blade cooling, the Return Flow Cascade, has been developed in which vaporization of a liquid metal such as potassium is used to maintain the blade surface at a nearly uniform temperature. Turbine blades cooled using this technology have lower blade temperature levels compared to that available with conventional air cooling, potentially resulting in higher firing temperatures or a choice of a wider range of materials for the hot gas path. The detailed operation of the Return Flow Cascade is described including fluid mechanic and heat transfer phenomena that occur at high heat flux and gravitational …

A Perching Landing Gear For A Quadcopter, Elsa Culler, Gray Thomas, Christopher Lee

Christopher Lee

The design, fabrication, and testing of two prototypes of a landing gear mechanism that would allow a quadcopter to grasp and perch upon a branch-like structure are presented. The prototypes are based upon a snapping-claw mechanism that is triggered on the impact of landing. A complaint claw, fabricated using shape deposition manufacturing techniques, can conform to various shapes and contours of perching structures. Results from flight tests with a commercial off-the-shelf quadcopter and zip line tests are presented which demonstrate the performance of the mechanism.

Joint Metering And Conflict Resolution In Air Traffic Control, Jerome Le Ny, George J. Pappas

George J. Pappas

This paper describes a novel optimization-based approach to conflict resolution in air traffic control, based on geometric programming. The main advantage of the approach is that Geometric Programs (GPs) can also capture various metering directives issued by the traffic flow management level, in contrast to most recent methods focusing purely on aircraft separation issues. GPs can also account for some of the nonlinearities present in the formulations of conflict resolution problems, while incurring only a small penalty in computation time with respect to the fastest linear programming based approaches. Additional integer variables can be introduced to improve the quality of …

Joint Metering And Conflict Resolution In Air Traffic Control, Jerome Le Ny, George J. Pappas

George J. Pappas

This paper describes a novel optimization-based approach to conflict resolution in air traffic control, based on geometric programming. The main advantage of the approach is that Geometric Programs (GPs) can also capture various metering directives issued by the traffic flow management level, in contrast to most recent methods focusing purely on aircraft separation issues. GPs can also account for some of the nonlinearities present in the formulations of conflict resolution problems, while incurring only a small penalty in computation time with respect to the fastest linear programming based approaches. Additional integer variables can be introduced to improve the quality of …

Joint Metering And Conflict Resolution In Air Traffic Control, Jerome Le Ny, George J. Pappas

George J. Pappas

This paper describes a novel optimization-based approach to conflict resolution in air traffic control, based on geometric programming. The main advantage of the approach is that Geometric Programs (GPs) can also capture various metering directives issued by the traffic flow management level, in contrast to most recent methods focusing purely on aircraft separation issues. GPs can also account for some of the nonlinearities present in the formulations of conflict resolution problems, while incurring only a small penalty in computation time with respect to the fastest linear programming based approaches. Additional integer variables can be introduced to improve the quality of …

End-Winding Leakage Of Aerospace Homopolar Alternators, Mulukutla S. Sarma

Sarma Mulukutla

An accurate knowledge of the magnetic field distribution is of great importance in finding the best designs for electrical machinery. It is the purpose of this paper to present a new numerical method for the determination of three-dimensional flux distribution in the end zone of a high-speed aerospace homopolar alternator, and for the calculation of end leakage reactance. The new analysis is applied to an experimental 95 kVA, 115/200 V, 3400 Hz, 40,800 r/min, three-phase, wye-connected, homopolar alternator.

Aircraft Operations Based Mission Requirements, Robert A. Mcdonald

Robert A. McDonald

The mission capabilities of aircraft in the current commercial fleet are a combined result of many factors. The launch customer for each aircraft has a voice in determining the requirements. The manufacturer desires to best position the aircraft in the market considering their own aircraft and their competitors aircraft it will replace and compete with. Consequently, anyone considering the development of an aircraft to compete with or replace an aircraft in-service must do more than simply choose to meet the capabilities of that aircraft. This is especially true when unconventional systems are considered; the fundamental trade-offs for these systems may …

State Of The Art / Novel Rotary-Turbo-Inflow Tech / Featured Development - Gearturbine Project - Atypical Motor Engine Type, Carlos Barrera

Carlos Barrera

GEARTURBINE PROJECT Atypical InFlow Thermodynamic Technology Proposal Submission Novel Fueled Motor Engine Type

*State of the art Innovative concept Top system Higher efficient percent. Have similar system of the Aeolipile Heron Steam device from Alexandria 10-70 AD. -New Form-Function Motor-Engine Device. Next Step, Epic Design Change, Broken-Seal Revelation. -Desirable Power-Plant Innovation.

YouTube; * Atypical New • GEARTURBINE / Retrodynamic = DextroRPM VS LevoInFlow + Ying Yang Thrust Way Type - Non Waste Looses

-This innovative concept consists of hull and core where are held all 8 bteps of the work-flow which make the concept functional. The core has several gears …

Open Orbiter Mission Architecture, Atif Mohammad, Jeremy Straub, Josh Berk, Nick Long, David Apostal, Anders Nervold, Brian Badders, Tyler Hill, Patrick Galegher, Donovan Torgerson

Jeremy Straub

No abstract provided.

Power Supply Electrical Design, Robert Mayers, Matt Olson, Zach Bryant, Ali Haider, Stephen Holmes, Paul Johnson, Noah Root, Josh Berk, Jeremy Straub

Jeremy Straub

No abstract provided.

Ground Support Station Team, Cassandra Johnson, Iva Gerasimenko, Aaron Podoll, Josh Berk, Jeremy Straub

Jeremy Straub

No abstract provided.

Operating Software, Donovan Torgerson, Miyuru Arangala, Michael Hlas, David Bullock, Dayln Limesand, Cameron Kerbaugh, Daniel Schuler, Mitchell Fossen, Edwin Carlson, Atif Mohammad, Josh Berk, Jeremy Straub

Jeremy Straub

No abstract provided.

Sensor And Bus Electrical Design, Tyler Przybylski, Prabhu Victor, Chris Mcdonald, Yineng Li, Noah Root, Josh Berk, Jeremy Straub

Jeremy Straub

No abstract provided.

Ground Station Software Model, David Apostal, Atif Mohammad, Jeremy Straub, Josh Berk

Jeremy Straub

No abstract provided.

Cubesat Software Architecture, Christoffer Korvald, Atif Mohammad, Jeremy Straub, Josh Berk

Jeremy Straub

No abstract provided.

Mechanical Team, Brian Badders, Tyler Hill, Alec Redmann, Erik Peterman, Wataru Suzuki, Josh Berk, Jeremy Straub

Jeremy Straub

No abstract provided.