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Full-Text Articles in Engineering
Shock Effects On Delta Wing Vortex Breakdown, Lucy A. Schiavetta, Okko J. Boelens, Simone Crippa, Russell M. Cummings, Willy Fritz, Ken J. Badcock
Shock Effects On Delta Wing Vortex Breakdown, Lucy A. Schiavetta, Okko J. Boelens, Simone Crippa, Russell M. Cummings, Willy Fritz, Ken J. Badcock
Aerospace Engineering
It has been observed that delta wings placed in a transonic freestream can experience a sudden movement of the vortex breakdown location as the angle of incidence is increased. The chapter reports on the use Computational Fluid Dynamics (CFD) to examine this behaviour in detail. The study shows that a shock-vortex interaction is responsible. The balance of the vortex strength and axial flow, and the shock strength, is examined to provide an explanation of the sensitivity of the breakdown location. Limited experimental data is available to supplement the CFD results in certain key respects, and the ideal synergy between CFD …
Numerical Solutions For The Cawapi Configuration On Unstructured Grids At Usafa, United States, Scott A. Morton, David R. Mcdaniel, Russell M. Cummings
Numerical Solutions For The Cawapi Configuration On Unstructured Grids At Usafa, United States, Scott A. Morton, David R. Mcdaniel, Russell M. Cummings
Aerospace Engineering
No abstract provided.
Numerical Solutions For The Vfe-2 Configuration On Unstructured Grids At Usafa, United States, Russell M. Cummings, Andreas Schϋtte
Numerical Solutions For The Vfe-2 Configuration On Unstructured Grids At Usafa, United States, Russell M. Cummings, Andreas Schϋtte
Aerospace Engineering
The numerical simulation of the flow for the VFE-2 configuration with rounded leading edges is presented. For the numerical simulation the Cobalt Code was used, which uses a cell-centered unstructured hybrid mesh approach. Several numerical results are presented for the steady RANS equations as well as for DES and DDES hybrid approaches. Within this paper the focus is related to the dual primary vortex flow topology, especially the sensitivity of the flow to angle of attack and Reynolds number effects. Reasonable results are obtained with both steady RANS and SA-DDES simulations. The results are compared and verified by experimental data, …
Lessons Learned From The Numerical Investigations On The Vfe-2 Configuration, Willy Fritz, Russell M. Cummings
Lessons Learned From The Numerical Investigations On The Vfe-2 Configuration, Willy Fritz, Russell M. Cummings
Aerospace Engineering
The Second International Vortex Flow Experiment provided a variety of experimental data for a 65° delta wing with sharp and blunt/rounded leading edges. Flow measurements including forces and moments, surface pressures, Pressure Sensitive Paint measurements, and off-surface flow variables from Particle Image Velocimetry were made available for comparisons with computational simulations. A number of test cases were chosen for simulation by seven numerical groups, and a summary of their results is presented here. The ability of computational fluid dynamics to predict such flow features as the dual primary vortex system found on the blunt leading edge configuration and a shock/vortex …
Cost-Benefit Analysis Of Error Reduction For Complex Systems, Robert A. Mcdonald
Cost-Benefit Analysis Of Error Reduction For Complex Systems, Robert A. Mcdonald
Aerospace Engineering
The cost-benefit tradeoff of analysis fidelity in complex systems analysis has been posed as an optimization problem providing quantitative guidance for investment in improving analysis. A nonlinear constrained optimizer to solve this problem has been integrated into an error tradeoff environment providing an intuitive tool for the decision maker to consider investment in fidelity at the same time as design decisions are considered. An example demonstrates the efficacy of the improved interface to enable fidelity improvement investment decisions.
Multidisciplinary Design Optimization Of An Extreme Aspect Ration Hale Uav, Bryan Morrisey, Robert A. Mcdonald
Multidisciplinary Design Optimization Of An Extreme Aspect Ration Hale Uav, Bryan Morrisey, Robert A. Mcdonald
Aerospace Engineering
Development of High Altitude Long Endurance (HALE) aircraft systems is part of a vision for a low cost communications/surveillance capability. Applications of a multi payload aircraft operating for extended periods at stratospheric altitudes span military and civil genres and support battlefield operations, communications, atmospheric or agricultural monitoring, surveillance, and other disciplines that may currently require satellite-based infrastructure. The central goal of this research was the development of a multidisciplinary tool for analysis, design, and optimization of HALE UAVs, facilitating the study of a novel configuration concept. Applying design ideas stemming from a unique WWII-era project, a "pinned wing" HALE aircraft …
Comparison Of Overset Grid And Grid Deformation Techniques Applied To 2-Dimensional Naca Airfoils, Charles M. Hoke, Robert K. Decker, Russell M. Cummings, David R. Mcdaniel, Scott A. Morton
Comparison Of Overset Grid And Grid Deformation Techniques Applied To 2-Dimensional Naca Airfoils, Charles M. Hoke, Robert K. Decker, Russell M. Cummings, David R. Mcdaniel, Scott A. Morton
Aerospace Engineering
This paper documents a comparison of overset grid and grid deformation schemes applied to flapped and non-flapped NACA airfoil configurations in order to determine the relative accuracy and computational efficiency of each method. This study is part of a larger effort to use computational fluid dynamics to perform moving control surface calculations. Three different cases, using both overset and deformed grids, are considered, including: a) lift and moment comparison of a quasi-steady, non-flapped 0012 airfoil, b) lift and moment comparison of a dynamically pitching non-flapped 0012 airfoil, and c) lift comparison of a dynamic pitching and oscillating flapped 0012 airfoil. …
Application Of Volterra Functions To X-31 Aircraft Model Motion, United States Air Force Academy, Russell M. Cummings
Application Of Volterra Functions To X-31 Aircraft Model Motion, United States Air Force Academy, Russell M. Cummings
Aerospace Engineering
Recent advances towards an efficient computational method for accurately determining the stability and control characteristics of an aircraft are discussed and critiqued. The present approach with greatest promise is to reduce the number of high-fidelity CFD simulations by using Volterra functions Reduced Order Modeling. This type of reduced order model is a predictive model which has a unique training maneuver -a unit impulse. The advantage of such an approach is the fast prediction of the aerodynamic characteristics of an aircraft. This article presents the results of application of the Volterra functions ROM for prediction of linear movement of a 2D …
Satellite Formation Flight Navigation Using The Clohessy-Wiltshire Equations, Anna Kimmich
Satellite Formation Flight Navigation Using The Clohessy-Wiltshire Equations, Anna Kimmich
Aerospace Engineering
This report presents the design and simulation of a satellite navigation program using Matlab. The program allows any number of independent satellites to navigate in a co-planar cluster formation in a circular orbit with no input besides its location coordinates from a simulated GPS unit and the relative location of other satellites from a simulated on-board sensor. This navigation program uses a potential field-like function to calculate the desired satellite position within the formation. It uses the Clohessy-Wiltshire equations to calculate the impulsive maneuvers needed to achieve and maintain the formation.
Lower-Order Aerodynamic Loads Modeling Of A Maneuvering Generic Fighter Using Ddes Simulations, Tiger L. Jeans, David R. Mcdaniel, Russell M. Cummings, Keith Bergeron
Lower-Order Aerodynamic Loads Modeling Of A Maneuvering Generic Fighter Using Ddes Simulations, Tiger L. Jeans, David R. Mcdaniel, Russell M. Cummings, Keith Bergeron
Aerospace Engineering
Unforeseen nonlinear aerodynamic behavior and/or fluid-structure interactions have affected the development of nearly every major fighter program since 1960. The development cost of each of these aircraft could have been drastically reduced if these aerodynamic issues had been identified earlier in the design process. Therefore, a high-fidelity computational tool capable of reliably predicting or identifying configurations susceptible to handling quality instabilities prior to flight test would be of great interest to the stability and control community. The United States Air Force Academy Modeling and Simulation Research Center and the United States Air Force Seek Eagle Office have initiated a joint …
John Mcmasters’Contributions To Aircraft Design Education, Russell M. Cummings
John Mcmasters’Contributions To Aircraft Design Education, Russell M. Cummings
Aerospace Engineering
John McMasters was intensely interested in two seemingly diverse pursuits: aircraft design and technical work force development. The later pursuit often got John involved in encouraging the development and improvement of engineering education, especially aircraft design education. He spent countless hours considering the issues that contribute to good design education, and was a strong proponent of programs that would encourage students to become interested in design. An overview of John’s ideas on aircraft design education will be presented based on discussions with John, as well as papers that we co-authored. In addition, John had a long talk with me just …
Decades Of Innovation In Aircraft Design Education, Russell M. Cummings, David W. Hall, Doral R. Sandlin
Decades Of Innovation In Aircraft Design Education, Russell M. Cummings, David W. Hall, Doral R. Sandlin
Aerospace Engineering
Aircraft design has formed the foundation of the aeronautical engineering curriculum at Cal Poly since the inception of the department in 1927. While the focus and approach for teaching aircraft design has changed a great deal over the decades, the importance of the Cal Poly “learn by doing” philosophy has been a constant element. The end result of this decades-long history of innovation and improvement has been the continued success of Cal Poly students in the AIAA design competitions, especially the Undergraduate Team Aircraft Design competition. Details about how the design curriculum has evolved and grown will be discussed, including …
Using Cfd As A Design Tool On New Innovative Airliner Configurations, Bryan H. Blessing, John Pham, David D. Marshall
Using Cfd As A Design Tool On New Innovative Airliner Configurations, Bryan H. Blessing, John Pham, David D. Marshall
Aerospace Engineering
This paper demonstrates the use of CFD thus far as a design tool in evaluating aerodynamic performance for a NASA Research Announcement (NRA) project. The NRA project is carried out in two phases over the course of three years. Phase I utilizes CFD to evaluate and down select between two proposed future generations CESTOL airliner concepts; the Hybrid Wing-Body and the Blended Wing-Body. Both configurations are simulated at takeoff and cruise conditions to provide the means to making a final decision on which concept to continue forward with in Phase II. This second phase will take the proposed airliner concept …
Propulsion System Modeling And Takeoff Distance Calculations For A Powered-Lift Aircraft With Circulation-Control Wing Aerodynamics, Mark Waters, Cassey Anthony, Gregory Mckenzie, David D. Marshall
Propulsion System Modeling And Takeoff Distance Calculations For A Powered-Lift Aircraft With Circulation-Control Wing Aerodynamics, Mark Waters, Cassey Anthony, Gregory Mckenzie, David D. Marshall
Aerospace Engineering
The computation of takeoff distance for powered-lift aircraft is complicated because of the coupling of aerodynamic performance (lift, drag and moment coefficients) with forward speed. Cal Poly has developed an analysis procedure to capture this coupling, and the development of this procedure is continuing. In the past year, Cal Poly has completed a Phase I NRA contract from the NASA for the configuration development and modeling of CESTOL aircraft. The primary objective of this contract was to identify an aircraft configuration in enough detail to proceed into a Phase II contract to design and construct a large scale wind tunnel …
A Surface Parameterization Method For Airfoil Optimization And High Lift 2d Geometries Utilizing The Cst Methodology, Kevin A. Lane, David D. Marshall
A Surface Parameterization Method For Airfoil Optimization And High Lift 2d Geometries Utilizing The Cst Methodology, Kevin A. Lane, David D. Marshall
Aerospace Engineering
For aerodynamic modeling and optimization, it is desirable to limit the number of design variables to reduce model complexity and the requirements of the applied optimization scheme. The Class/Shape Transformation (CST) surface parameterization method presented by Kulfan has proven to be particularly useful for this while maintaining a wide range of applications. These include everything from smooth airfoils to 3D axi-symmetric bodies and wings. However, the CST method is confined to smooth geometries. This limits the CST method in applications incorporating discontinuous surfaces such as high lift aerodynamics with circulation control (CC) slots and flaps. The trailing edge slot on …
Underpowered Aircraft - Performance And Operational Possibilities, Andrew S. Ezzard, Michael R. Vallone, Robert A. Mcdonald
Underpowered Aircraft - Performance And Operational Possibilities, Andrew S. Ezzard, Michael R. Vallone, Robert A. Mcdonald
Aerospace Engineering
A unique configuration, known as an Underpowered Aircraft, allows for the modification of gliding flight vehicles for increased range and lower cost when compared with fully powered flight vehicles. Intentionally under-sizing the powerplant for a flight vehicle allows the designer to choose a powerplant that will not only perform the mission requirements, but will also provide the customer with the most cost effective solution, as some missions may not require fully powered flight. Specifically, the underpowered aircraft concept studied in this paper is a gliding flight aircraft that does not have enough power for climbing or level flight, but does …
A User Friendly Interface For Gaussian Process Metamodeling, Collin R. Baukol, Robert A. Mcdonald, Nicholas Delmas
A User Friendly Interface For Gaussian Process Metamodeling, Collin R. Baukol, Robert A. Mcdonald, Nicholas Delmas
Aerospace Engineering
As research into metamodeling and using advanced metamodeling techniques continues, it is important to remember design engineers who need to use these advancements. Even experienced engineers may not be well versed in the material and mathematical background that is currently required to generate and fully comprehend advanced complex metamodels. A user friendly metamodeling environment is being developed to help bridge the gap that is currently growing between the research community and the design engineers. This tool allows users to easily create, modify, and assess the quality of metamodels.
Senior Design At Cal Poly: A Recipe For Success, Robert A. Mcdonald, Jordi Puig-Suari, Dave Esposto, Bruce Wright
Senior Design At Cal Poly: A Recipe For Success, Robert A. Mcdonald, Jordi Puig-Suari, Dave Esposto, Bruce Wright
Aerospace Engineering
The Aerospace Engineering Department at Cal Poly has, over the years, evolved a unique recipe for Senior Design. This recipe has been applied to the capstone Aircraft and Spacecraft design courses and will soon be extended to an Unmanned Aerial Vehicle design course. This recipe consists primarily of a year long design sequence with a great deal of participation from the region's aerospace industry. The Cal Poly recipe has proven to be both flexible and effective. The authors believe it could be adapted and applied in a similar manner at other institutions with a similar degree of success.
Comparisons Of Computational Fluid Dynamics Solutions Of Static And Manoeuvering Fighter Aircraft With Flight Test Data, David R. Mcdaniel, Russell M. Cummings, K. Bergeron, Scott A. Morton, J. P. Dean
Comparisons Of Computational Fluid Dynamics Solutions Of Static And Manoeuvering Fighter Aircraft With Flight Test Data, David R. Mcdaniel, Russell M. Cummings, K. Bergeron, Scott A. Morton, J. P. Dean
Aerospace Engineering
As the capabilities of computational fluid dynamics (CFD) to model full aircraft configurations improve, and the speeds of massively parallel machines increase, it is expected that CFD simulations will be used more and more to steer or in some cases even replace traditional flight test analyses. The mission of the US Air Force SEEK EAGLE office is to clear any new weapon configurations and loadings for operational use. As more complex weapons are developed and highly asymmetric loadings are requested, the SEEK EAGLE office is tasked with providing operational clearances for literally thousands of different flight configurations. High-fidelity CFD simulations …