The evolution of an FR-80 generated movie of opposed jet fluid flow

Abstract

Computer generated graphics play an important role in the numerical modeling of natural phenomena, for example, turbulent and laminar fluid flow, heat transfer, stress analysis, and phase transition. The importance of graphical capabilities was recently reported by Tunstall and Elrod [i], when 35 mm slides generated by the FLOWPLOT [2] program were presented. The advantage of computer generated movies can be seen by the fact that with a movie, not only the data, but any trends within the data can be noted immediately. This paper discusses some of the ideas used by the authors to generate a movie on an FR-80 Graphics Recorder. Before the actual work of generating a movie began, the authors searched the local libraries for literature concerning computer generated movies. Documentation on two movie generating programs and several articles concerning documentary films were found, but there was no information on converting an existing computer graphics program into a movie producing program. The ideas that are presented here are the result of the authors' experiences in producing a movie from an existing plotting program, FLOWPLOT. FLOWPLOT was designed to be used with numerical fluid dynamics (or heat transfer with convection) codes to create velocity plots and/or pressure, density, and temperature contour plots [2]. Results of numerical experiments on a model of gas flow behavior in an opposing jet separation system were reported by J. N. Tunstall [3] using a movie generated by FLOWPLOT. In order to produce a movie by plotting directly on the film, the user must have available a high speed 16 mm pin-registered film plotter. Since the minimum movie projector speed is approximately 16 frames per second, the number of frames required for even a short film is significant. The number of frames that must be plotted to make a movie of a desired length is shown in Table i. Forty frames are drawn per foot of 16 mm film.