Aerospace Engineering Commons^™

Constrained Kalman Filtering Via Density Function Truncation For Turbofan Engine Health Estimation, Daniel J. Simon, Donald L. Simon

Electrical and Computer Engineering Faculty Publications

Kalman filters are often used to estimate the state variables of a dynamic system. However, in the application of Kalman filters some known signal information is often either ignored or dealt with heuristically. For instance, state variable constraints (which may be based on physical considerations) are often neglected because they do not fit easily into the structure of the Kalman filter. This article develops an analytic method of incorporating state variable inequality constraints in the Kalman filter. The resultant filter truncates the probability density function (PDF) of the Kalman filter estimate at the known constraints and then computes the constrained …

Adaptive Control Applied To The Cal Poly Spacecraft Attitude Dynamics Simulator, Matthew C. Downs

Master's Theses

The goal of this thesis is to use the Cal Poly Spacecraft Attitude Dynamics Simulator to provide proof of concept of two adaptive control theories developed by former Cal Poly students: Nonlinear Direct Model Reference Adaptive Control and Adaptive Output Feedback Control. The Spacecraft Attitude Dynamics Simulator is a student-built air bearing spacecraft simulator controlled by four reaction wheels in a pyramidal arrangement. Tests were performed to determine the effectiveness of the two adaptive control theories under nominal operating conditions, a “plug-and-play” spacecraft scenario, and under simulated actuator damage. Proof of concept of the adaptive control theories applied to attitude …

Improved Geometry Modeling For High Fidelity Parametric Design, James R. Gloudemans, Robert A. Mcdonald

Aerospace Engineering

Advanced multidisciplinary physics-based design and analysis capabilities are required to pursue the revolutionary vehicle and technology concepts needed to meet the goals of the aerospace industry for the next 10-30 years. The multidisciplinary physics critical to advancing aerospace technology all have one common bond, the shape, size, and form of the underlying aircraft - its geometry. An aircraft shape is the natural starting point for multidisciplinary analysis and optimization (MDAO). Vehicle Sketch Pad (VSP) is an aircraft geometry tool for rapid evaluation of advanced design concepts which was developed by NASA and is available to industry at large. VSP allows …

Conceptual Design Of A Next Generation, 150 Passenger Commercial Transport, Ryan Halper, Kevin Lane, Dustin Marschik, Brett Morham, John Pham, Robert A. Mcdonald, Bruce Wright

Aerospace Engineering

In response to the 2008-2009 AIAA Undergraduate Team Design Competition's Request for Proposals for an advanced, environmentally compatible, 150 seat commercial transport; Jackson West has designed the Sparrow JS-3. The Sparrow represents the next step in the evolution of commercial aviation. Scheduled to enter service in 2018, The Sparrow will compete directly with the Boeing 737 and Airbus A320. Its improvements in fuel consumption and operating cost, as well as its reduced environmental impact, make The Sparrow the ideal solution to this RFP.

Assessment Of Sting Effect On X-31 Aircraft Model Using Cfd, Adam Jirásek, Russell M. Cummings

Aerospace Engineering

The article describes the computational evaluation of the effect a belly mounted sting on the aerodynamics characteristics of an X-31 wind tunnel model. The investigation includes results of steady and time-dependent CFD analysis of the X-31 model with and without sting. The values of the steady lift and pitching moment coefficients as well as the pitching moment of model undergoing a manuever are compared to each other and to the wind tunnel data. The results of this analysis show the detrimental effect of sting on stability of the vortical structure above the wing as well as a substantial increase of …

Overview Of Recent Circulation Control Modeling Activities At Cal Poly, David D. Marshall, Kristina K. Jameson

Aerospace Engineering

This paper provides an overview of the Circulation Control modeling research that has been performed, and is still ongoing, at Cal Poly, San Luis Obispo. This work started in 2005 with the interest of applying Circulation Control technologies to advanced aircraft designs. After the initial investigations into this, it was apparent that there was a long history of experimental work in this area to build on, but a number of deficiencies existed in the modeling capabilities. For Circulation Control enabled aircraft, these included: few available tools to accurately model the takeoff and landing performance, the limitations in the standard regulations …

Improved Methodologies For Maneuver Design Of Aircraft Stability And Control Simulations, Adam Jirásek, Tiger L. Jeans, Mathew Martenson, Russell M. Cummings, Keith Bergeron

Aerospace Engineering

With many modern fighter aircraft experiencing unpredicted flight dynamics during flight tests, recent research has focused on developing methodologies for incorporating computational fluid dynamics into the aircraft development process. The goal of this approach is to identify configurations susceptible to stability and control issues early in the design process. Previous research has primarily focused on full aircraft configurations, however, to increase the rate of development the current study focused on a two-dimensional NACA0012 airfoil. The two-dimensional NACA0012 airfoil has the advantage of reducing the computational cost by orders of magnitude compared to full scale aircraft simulations, while still providing complicated …

Parameter Estimation Of Fundamental Technical Aircraft Information Applied To Aircraft Performance, Mike Vallone, Robert A. Mcdonald

Aerospace Engineering

Inverse problems can be applied to aircraft in many areas. One of the disciplines within the aerospace industry with the most openly published data is in the area of aircraft performance. Many aircraft manufacturers publish performance claims, flight manuals and Standard Aircraft Characteristic (SAC) charts without any mention of the more fundamental technical information such as C_D0. With accurate tools, generalized aircraft models and a few curve-fitting techniques, it is possible to evaluate vehicle performance and estimate these technical parameters.

With this goal a program has been written in Matlab to calculate the fundamental information behind a …

Designing A Green Aircraft: Cal Poly's 2009 Undergraduate Aircraft Designs, Robert A. Mcdonald, Bruce Wright

Aerospace Engineering

The Cal Poly senior design class submitted six designs this year in response to the 2009 Undergraduate Team Aircraft Design Competition. This paper summarizes our experiences teaching design through this RFP and brings the student's insights together.

Conceptual Design Of An Environmentally Responsible 150-Passenger Commercial Aircraft, Natalie R. Smith, Bryan Blessing, James Dixon, Allen Mackey, Gregory Mckenzie, Robert A. Mcdonald, Bruce Wright

Aerospace Engineering

Verde is an environmentally responsible commercial transport seating 150 dual-class passengers, designed in response to the 2008-2009 Request for Proposal from the American Institute of Aeronautics and Astronautics Undergraduate Team Aircraft Design Competition. While the airline industry faces increasing pressures from the cost of fuel and the responsibility of environmental impact, the next generation of this aircraft class must operate more efficiently and address those environmental needs. Therefore, all design decisions for Verde focused first on reducing fuel burn, second on reducing emissions, then noise, and finally on maintaining flyaway cost, airport integration, and passenger comfort. The final design utilizes …

Lift Superposition And Aerodynamic Twist Optimization For Achieving Desired Lift Distributions, Kevin A. Lane, David D. Marshall, Robert A. Mcdonald

Aerospace Engineering

A method for achieving an arbitrary lift distribution with an arbitrary planform is presented. This is accomplished through optimizing aerodynamic twist for a given number of either known airfoils or airfoils to be designed. The spanwise locations of these airfoils are optimized to get as close to the desired lift distribution as possible. Airfoils are linearly interpolated between these points. After aerodynamic twist, the planform is twisted geometrically using radial basis functions to model the twist distribution. The aerodynamic influence of each twist distribution is determined and all are superimposed to determine the function weights of each twist function, yielding …

A Three Dimensional Vortex Particle-Panel Method For Modeling Propulsion-Airframe Interaction, Jacob S. Calabretta, Robert A. Mcdonald

Aerospace Engineering

The panel code has been a pivotal tool for aerodynamic simulations for decades, today providing users with quick solutions without the necessity of a volume grid. Unfortunately, the panel code also carries with it some inherent shortcomings when compared with other methods. One such weakness is its inability to account for any work done on or by the system in question. This paper proposes a method to address this issue by combining vortex particles with a panel code, and using them to model the work effects of a propeller or engine. While the proposed model is still a work in …

Computational And Experimental Comparison Of A Powered Lift, Upper Surface Blowing Configuration, Jay Marcos, David D. Marshall

Aerospace Engineering

This paper demonstrates the use of CFD as a validation tool for wind tunnel data on 2D high lift airfoil with a 3D engine performed by Georgia Tech Research Institute. Results of this validation will assist in determining the appropriate turbulence models, boundary conditions, mesh characteristics and other CFD modeling techniques necessary to capture the complicated flow physics associated with the coupling of circulation control wings and engine exhaust flows. It was found that grid issues and the two-equation turbulence model, k-ε, over predicted lift as blowing momentum increases even with the additional complexity of having an over the wing …

Design And Performance Of Circulation Control Flap Systems, Rory M. Golden, David D. Marshall

Aerospace Engineering

The design of circulation control (CC) dual radius flap systems were investigated to characterize the parameters that make up the flap surface to offer further knowledge into the CC field of study. Multiple dual radius flap geometries, along with variants, were developed by varying specific flap parameters from a baseline configuration that had previously developed. The aerodynamics of the different flap geometries were analyzed using two-dimensional CFD. This research will explore the design of CC pneumatic flap systems to improve the performance of existing CC flap configurations, and provide insight into the characteristics of the CC flap geometry.

Towards Efficient Viscous Modeling Based On Cartesian Methods For Automated Flow Simulation, Patrick Hu, Hongwu Zhao, Ramji Kamakoti, Nagendra Dittakavi, Liping Xue, Kan Ni, Shaolin Mao, David D. Marshall, Michael Aftosmis

Aerospace Engineering

The advanced Computational Fluid Dynamics (CFD) techniques that address the current limitations of Cartesian-based Navier-Stokes CFD schemes are explored in current investigation. Three promising methods of implementing improved wall boundary conditions are applied: (1) the enhanced diamond path stencil approach, (2) the reformulated extended extrapolation boundary condition, and (3) the ghost cell method. Several initial testing cases have been conducted with all these three boundary conditions, including the flow past a circular cylinder, flow past a flat plate at different inclined angles and flow past an AGARD RAE2822 airfoil. All the results show the effectiveness of these boundary conditions in …

Inverse Airfoil Design Utilizing Cst Parameterization, Kevin A. Lane, David D. Marshall

Aerospace Engineering

An inverse airfoil design process is presented that makes use of the CST parameterization method. The CST method is very powerful in that it can easily represent any airfoil shape within the entire design space of smooth airfoils. This makes it an ideal modeling technique for an inverse design process because accurate airfoil geometry treatment is required. The downfall of some inverse design processes is that they do not accurately handle the leading edge region due to large flow gradients and high curvature distributions. One way to account for this is by representing airfoils with smooth analytic functions, such as …

Assessing The V2-F Turbulence Models For Circulation Control Applications, Travis M. Storm, David D. Marshall

Aerospace Engineering

This paper explores the applicability of several variations of the v²-f turbulence model to circulation control flows. The effects of modifying the model to capture nonlinear eddy viscosity effects and streamline curvature effects are assessed. Results indicate that the v²-f turbulence model is capable producing more physically accurate results for circulation control flow fields than common modern turbulence modeling techniques.

Numerical Investigation Of Aeroelastic Mode Distribution For Aircraft Wing Model In Subsonic Air Flow, Marianna A. Shubov, Stephen B. Wineberg, Robert Holt

Mathematics & Statistics

In this paper, the numerical results on two problems originated in aircraft wing modeling have been presented. The first problem is concerned with the approximation to the set of the aeroelastic modes, which are the eigenvalues of a certain boundary-value problem. The affirmative answer is given to the following question: can the leading asymptotical terms in the analytical formulas be used as reasonably accurate description of the aeroelastic modes? The positive answer means that these leading terms can be used by engineers for practical calculations. The second problem is concerned with the flutter phenomena in aircraft wings in a subsonic, …

Multiscale Transformation Field Analysis Of Progressive Damage In Fibrous Laminates, Yehia Bahei-El-Din, Ritesh Khire, Prabhat Hajela

Centre for Advanced Materials

As part of an ongoing effort to model uncertainty propagation across multiple scales in fibrous laminates, this paper presents a deterministic transformation field analysis for modeling damage progression under membrane forces and bending moments. In this approach, equivalent eigenstresses are computed in the phases and/or plies such that their respective stress components that satisfy the underlying failure criteria are reduced to zero. Superposition of the solutions found for the undamaged laminate under applied loads and under the eigenstress field provide the entire response. Failure criteria are based on stress averages in the fiber and matrix. Damage mechanisms considered are frictional …

Modified Sandwich Structures For Improved Impact Resistance Of Wind Turbine Blades, Yehia Bahei-El-Din, Mostafa Shazly, I. El-Habbal, Y. Elbahy

Centre for Advanced Materials

Wind turbine blades are susceptible to damage due to fatigue as well as impact by flying objects and parts broken off failed blades of nearby wind towers. Localized, permanent compression of the foam core and delamination of the fibrous composite face sheets are typical damage modes and can lead to progressive structural failure. Sandwich structures modified by inclusion of flexible polyurethane (PU) layers within the cross section are examined under both impact and dynamic loads. Finite element models of sandwich structures with conventional and modified designs show that sandwich designs modified with PU interlayes exhibit reduced foam core crushing and …