Computational Fluid Dynamics
Innovators have long turned to technology for better ways to perform familiar tasks. For William Froude, that meant creating a controlled environment for his scale model experiments. David Taylor wanted a similar environment for his work, taking Froude’s
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Computational Fluid Dynamics
The physical aspects of any fluid flow are governed by the following three fundamental principles: (1) mass is conserved; (2) F = ma (Newton’s second law); and (3) energy is conserved. These fundamental principles can be expressed in terms of mathematical equations, which in their most general form are usually partial differential equations. Computational fluid dynamics is, in part, the art of replacing the governing partial differential equations of fluid flow with numbers, and advancing these numbers in space and/or time to obtain a final numerical description of the complete flow field of interest. John D. Anderson, Computational Fluid Dynamics: An Introduction
Innovators have long turned to technology for better ways to perform familiar tasks. For William Froude, that meant creating a controlled environment for his scale model experiments. David Taylor wanted a similar environment for his work, taking Froude’s results as a starting point and pushing forward to new levels of accomplishment. Not long after, the Wilbur and Orville Wright realized they could use models in a controlled environment to perfect the design of their flying machines. When the time came to head for the moon, Robert Goddard was there with his rocket prototypes. Each of these men built upon the theories, science, and discoveries of those who came before them, but innovation and new technologies did not end with them. New challenges arose with the increasing complexity of weapons like the intercontinental ballistic missile (ICBM) and vehicles for the peaceful manned exploration of space. These new vessels could not be readily tested. The calculations involved in predicting the performance of blunt bodies (those with a rounded nose) like the ICBM were too complex for the methods that had worked in the past. A new technology was needed, one that would allow the virtual modeling of behavior in a fluid field. That new technology arrived in the form of the computer in the late 1950s and early 1960s. With the computer, it was possible for calculations to be done in a
G. Hagler, Modeling Ships and Space Craft: The Science and Art of Mastering the Oceans and Sky, DOI 10.1007/978-1-4614-4596-8_11, © Springer Science+Business Media, LLC 2013
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fraction of the time they normally would have taken. But which calculations were the important ones and how could the results be judged?
Virtual Testing Virtual testing makes use of existing data to arrive at predictions about the behavior of a design. The better the fit of the new design to the old design, the more reliable the outcomes will be since the models that are used to perform the calculations are based on the current body of relevant knowledge. That is why scale model tests are still made today. The biggest change is that these physical tests are generally made near the end of the design cycle. Especially in the case of wind tunnel testing where the cost of the testing can be prohibitive, using CFD for the preliminary analysis
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