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Daniel Guggenheim School of Aerospace Engineering
Daniel Guggenheim School of Aerospace Engineering
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ItemValidation of APAS Aerodynamic Predictions with a Navier-Stokes CFD Analysis of a Hankey-Wedge Forebody(Georgia Institute of Technology, 1999-12-09) Sorensen, KirkWhile in the conceptual design phase of launch vehicles, aerodynamic data is often obtained through the use of a simple analytic program called APAS (Aerodynamic Preliminary Analysis System). While suffering from an archaic and temperamental interface, APAS yields results swiftly for simple geometries at a variety of angles of attack and Mach numbers. The results from APAS are compared to those obtained through the analysis of the same vehicle shape using a sophisticated CFD program called GASP (General Aerodynamic Simulation Program). The comparison is made on the forebody for the Stargazer Bantam launch vehicle, which is based on a Hankey-wedge design. Significant differences are noted and techniques to improve the accuracy of APAS output data are suggested
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ItemHierarchical robust nonlinear switching control design for propulsion systems(Georgia Institute of Technology, 1999-12) Leonessa, Alexander
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ItemTail buffet alleviation of high performance twin tail aircraft using offset piezoceramic stack actuators and acceleration feedback control(Georgia Institute of Technology, 1999-12) Bayon De Noyer, Maxime P.
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ItemSimulation of wheels in nonlinear, flexible, multibody systems(Georgia Institute of Technology, 1999-12) Rodriguez, Jesus
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ItemHyperion: An SSTO Vision Vehicle Concept Utilizing Rocket-Based Combined Cycle Propulsion(Georgia Institute of Technology, 1999-11) Olds, John R. ; Bradford, John Edward ; Charania, Ashraf ; Ledsinger, Laura Anne ; McCormick, David Jeremy ; Sorensen, KirkThis paper reports the findings of a conceptual launch vehicle design study performed by members of the Space Systems Design Laboratory at Georgia Tech. Hyperion is a conceptual design for an advanced reusable launch vehicle in the Vision Vehicle class. It is a horizontal takeoff, horizontal landing SSTO vehicle utilizing LOX/LH2 ejector scramjet rocket-based combined cycle (RBCC) propulsion. Hyperion is designed to deliver 20,000 lb. to LEO from the Kennedy Space Center. Gross weight is estimated to be 800,700 lb. and dry weight is estimated to be 123,250 lb. for this mission. Preliminary analysis suggests that, with sufficient launch traffic, Hyperion recurring launch costs will be under 200 dollars per lb. of payload delivered to LEO. However, nonrecurring costs, including development cost and acquisition of three airframes, is expected to be nearly 10.7B dollars. The internal rate of return is only expected to be 8.24 percent. Details of the concept design including external and internal configuration, mass properties, engine performance, trajectory analysis, aeroheating results, and concept cost assessment are given. Highlights of the distributed, collaborative design approach and a summary of trade study results are also provided.
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ItemStargazer: A TSTO Bantam-X Vehicle Concept Utilizing Rocket-Based Combined Cycle Propulsion(Georgia Institute of Technology, 1999-11) Olds, John R. ; Ledsinger, Laura Anne ; Bradford, John Edward ; Charania, Ashraf ; McCormick, David Jeremy ; Komar, D. R.This paper presents a new conceptual launch vehicle design in the Bantam-X payload class. The new design is called Stargazer. Stargazer is a two-stage-to-orbit (TSTO) vehicle with a reusable flyback booster and an expendable LOX/RP upper stage. Its payload is 300 lbs. to low earth orbit. The Hankey wedge- shaped booster is powered by four LOX/LH2 ejector scramjet rocket-based combined-cycle engines. Advanced technologies are also used in the booster structures, thermal protection system, and other subsystems. Details of the concept design are given including external and internal configuration, mass properties, engine performance, trajectory analysis, aeroheating results, and a concept cost assessment. The final design was determined to have a gross mass of 115,450 lb. with a booster length of 99 ft. Recurring price per flight was estimated to be $3.49M. The overall conceptual design process and the individual tools and processes used for each discipline are outlined. A summary of trade study results is also given.
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ItemIntegrating Aeroheating and TPS into Conceptual RLV Design(Georgia Institute of Technology, 1999-11) Cowart, Karl K. ; Olds, John R.The purpose of this study is to develop the Thermal Calculation Analysis Tool (TCAT) that will enable Aeroheating and Thermal Protection System (TPS) sizing to be, an on-line, automated process. This process is described as dynamic on-line TPS sizing. It enables the assumptions made about the vehicle TPS to be updated through out the iteration-process. This method is faster and more accurate than a static offline process where the assumptions of the vehicle TPS are held constant during the vehicle design procedure. TCAT will work in conjunction with other engineering disciplines in a Design Structure Matrix (DSM). The unsteady, one dimensional heat diffusion equation was discretized, and resulted in a tridiagonal system of non-linear algebraic equations. This system was implicitly solved using the iterative Newton-Raphson technique at each time level. This technique was conducted for both steady-state and transient conditions that predicted the temperature profiles, and in-depth conduction histories for several TPS material test cases. Also, this was performed on several disparate TPS materials layered together at one time. Finally; comparative benchmark solutions of the TCAT transient analyses were conducted using the commercial software code SINDA/G. Results show that TCAT performed as predicted, and will satisfy the requirement of lowering the amount of time required to conduct TPS sizing for a reusable launch vehicle. Future work will consist of adding temperature dependent material properties to TCAT, coupling TCAT to an optimizer, and creating a web-interface that will enable cross-platform operation of TCAT.
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ItemViable Designs Through a Joint Probabilistic Estimation Technique(Georgia Institute of Technology, 1999-10) Bandte, Oliver ; Mavris, Dimitri N. ; DeLaurentis, Daniel A.A key issue in complex systems design is measuring the 'goodness' of a design, i.e. finding a criterion through which a particular design is determined to be the 'best.' Traditional choices in aerospace systems design, such as performance, cost, revenue, reliability, and safety, individually fail to fully capture the life cycle characteristics of the system. Furthermore, current multi-criteria optimization approaches, addressing this problem, rely on deterministic, thus, complete and known information about the system and the environment it is exposed to. In many cases, this information is not be available at the conceptual or preliminary design phases. Hence, critical decisions made in these phases have to draw from only incomplete or uncertain knowledge. One modeling option is to treat this incomplete information probabilistically, accounting for the fact that certain values may be prominent, while the actual value during operation is unknown. Hence, to account for a multi-criteria as well as a probabilistic approach to systems design, a joint-probabilistic formulation is needed to accurately estimate the probability of satisfying the criteria concurrently. When criteria represent objective/ aspiration functions with corresponding goals, this ?int probability?can also be called viability. The proposed approach to probabilistic, multi-criteria aircraft design, called the Joint Probabilistic Decision Making (JPDM) technique, will facilitate precisely this estimate.
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ItemAn Improved Process for the Generation of Drag Polars for Use in Conceptual/Preliminary Design(Georgia Institute of Technology, 1999-10) Mavris, Dimitri N. ; Qiu, SongtaoOne of the most essential contributors in the aircraft sizing and synthesis process is the creation and utilization of accurate drag polars. An improved general procedure to generate drag polars for conceptual and preliminary design purposes in the form of Response Surface Equations is outlined and discussed in this paper. This approach facilitates and supports aerospace system design studies as well as Multi-disciplinary Analysis and Optimization. The analytically created Response Surface Equations replace the empirical aerodynamic relations or historical data found in sizing and synthesis codes, such as the Flight Optimization System (FLOPS). These equations are commonly incorporated into system level studies when a configuration falls beyond the conventional realm. The approach described here is a statistics-based methodology, which combines the use of Design of Experiments and Response Surface Method (RSM). Computational aerodynamic codes based on linearized potential flow and boundary layer theory are employed to generate the needed parametric relationships. The process is facilitated through the use of an automated computational architecture that is capable of handling massive exchanges of data and information. The aforementioned process is demonstrated through an implementation of the procedure for a High Speed Civil Transport concept. The accuracy of these Response Surface Equations is finally tested to demonstrate the fidelity and accuracy of their predictive capability.
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ItemThe Implementation of a Conceptual Aerospace Systems Design and Analysis Toolkit(Georgia Institute of Technology, 1999-10) Hale, Mark A. ; Mavris, Dimitri N. ; Carter, Dennis L.The Conceptual Aerospace Systems Design and Analysis Toolkit (CASDAT) provides a baseline assessment capability for the Air Force Research Laboratory. The historical development of CASDAT is of benefit to the design research community because considerable effort was expended in the classification of the analysis tools. Its implementation proves to also be of importance because of the definition of assessment use cases. As a result, CASDAT is compatible with accepted analysis tools and can be used with state-of-the- art assessment methods, including technology forecasting and probabilistic design.