2.0 INTRODUCTION A series of individual computer programs for design or analysis of supersonic configurations has been linked together into a single system.The system, because of built-in communication between the programs,is substantially simpler to input and use than the individual programs operating in a stand-alone mode.In addition,a common geometry format,based on the NASA-LRC configuration plotting program,has been adopted to standardize the input requirements of the basic programs. Interactive graphics have been included in the system,to display or edit input and to permit monitoring and readout of program results.The graphics arrangement is tailored specifically to the NASA-LRC CDC 250 cathode ray tube and associated software.However,all graphics applications have been sub- routined to the main programs and could be readily converted to a different graphics setup. Because the segment of the computer program which calculates skin friction drag (page 71)requires input of altitude in thousands of feet and Reynolds number in millions per foot,SI units have not been used. 3
2.0 INTRODUCTION A series of individual computer programsfor design or analysis of supersonic configurations has been linked together into a single system. The system, because of built-in communication between the programs, is substantially simpler to input and use than the individual programs operating in a stand-alone mode. In addition, a commongeometry format, based on the NASA-LRCconfiguration plotting program, has been adopted to standardize the input requirements of the basic programs. Interactive graphics have been included in the system, to display or edit input and to permit monitoring and readQut of program results. The graphics arrangement is tailored specifically to the NASA-LRCCDC250 cathode ray tube and associated software. However, all graphics applications have been subroutined to the main programs and could be readily converted to a different graphics setup. Becausethe segment of the computer program which calculates skin friction drag (page 71) requires input of altitude in thousands of feet and Reynolds number in millions per foot, SI units have not been used
3.0 DISCUSSION A schematic of the design and analysis system is shown in figure 3.0-1.The system consists of an executive "driver"and eight basic computer programs including a plot program and a geometry input module,which are used to build up the force coefficients of a selected configuration as shown in figure 3.0-2.The system may be used with or without interactive graphics. The complete design and analysis system is a single overlaid computer program, with the executive driver as the main overlay and the basic programs as pri- mary overlays.The basic programs manipulate input (geometry module),draw a picture of the configuration (plot module),or perform design or analysis calculations. Aerodynamic force coefficients for a selected configuration are built up through superposition.The individual modules of the system provide data for the force coefficient buildup as follows: Skin friction is computed using flat plate turbulent theory. ● Wave drag is calculated from either near-field (surface pressure integration)or far-field (supersonic area rule)methods.The near-field method is used primarily as an analysis tool,where detailed pressure distributions are of interest.The far-field method is used for wave drag coefficient calculations and for fuselage optimization according to area rule concepts. ● Drag-due-to-lift is computed from the lift analysis program,which breaks arbitrary wing/fuselage/canard/nacelles/horizontal tail configurations into a mosaic of "Mach-box"rectilinear elements which are employed in linear theory solutions.A complementary wing design and optimization program,also using the Mach-box approach,solves for the wing shape required to support an optimized pressure distribution at a specified flight condition. 3.1 System Communications Communication between the executive and the different basic modules is performed by disk files and limited common block storage. 1) Input A11 input to the basic modules is handled through the common geometry module and its associated interfaces.A fundamental consideration in the setup of the system has been that input to the basic modules would not be changed by their incorporation into the overall system. However,to minimize and simplify system input requirements,a special geometry module has been created to read all input,and then sort and structure the input needs of the basic programs. 5
3.0 DISCUSSION A schematic of the design and analysis system is shown in figure 3.0-1. The system consists of an executive "driver" and eight basic computer programs including a plot program and a geometry input module, which are used to build up the force coefficients of a selected configuration as shown in figure 3.0-2. The system may be used with or without interactive graphics. The complete design and analysis system is a single overlaid computer program, with the executive driver as the main overlay and the basic programs as primary overlays. The basic programs manipulate input (geometry module), draw a picture of the configuration (plot module), or perform design or analysis calculations. Aerodynamic force coefficients for a selected configuration are built up through superposition. The individual modules of the system provide data for the force coefficient buildup as follows: m Skin friction is computed using flat plate turbulent theory. Wave drag is calculated from either near-field (surface pressure integration) or far-field (supersonic area rule) methods. The near-field method is used primarily as an analysis tool, where detailed pressure distributions are of interest. The far-field method is used for wave drag coefficient calculations and for fuselage optimization according to area rule concepts. Drag-due-to-lift is computed from the lift analysis program, which breaks arbitrary wing/fuselage/canard/nacelles/horizontal tail configurations into a mosaic of "Mach-box" rectilinear elements which are employed in linear theory solutions. A complementary wing design and optimization program, also using the Mach-box approach, solves for the wing shape required to support an optimized pressure distribution at a specified flight condition. 3.1 System Communications Communication between the executive and the different basic modules is performed by disk files and limited common block storage. 1) Input All input to the basic modules is handled through the common geometry module and its associated interfaces. A fundamental consideration in the setup of the system has been that input to the basic modules would not be changed by their incorporation into the overall system. However, to minimize and simplify system input requirements, a special geometry module has been created to read all input, and then sort and structure the input needs of the basic programs
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