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FLUID MAPPERS AS VISUAL ANALOGS FOR POTENTIAL FIELDS
Author(s) -
Moore A. D.
Publication year - 1955
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.1955.tb40080.x
Subject(s) - citation , annals , computer science , library science , information retrieval , history , classics
In a fluid mapper, streamline fluid flow is made to occur in a thin flow space between an upper and a lower member. The upper member is a flat piece of plate glass, called the plate. The lower member may be a slab of suitable material, usually plaster, or the surface of a “sandbed,” or a combination of the two. The photographs reproduced herewith represent all three types. Normally, the two members are operated totally immersed in a tray of the operating fluid. When a given potential field situation is to be portrayed, the lower member of the fluid mapper is built to scale, with suitable boundaries, open or closed; islands, if any; one or more sources or sinks; and so on. Each source or sink is connected by a rubber tube to a tank, so that raising or lowering a tank will induce flow in the flow space. When the operation is conducted so that the flow is not affected by inertia, the flow pattern set up can quite accurately duplicate either the equipotential lines, or else the flux lines, of the potential field under consideration. Visible flow lines are produced, typically, by the use of potassium permanganate crystals. If the crystals are sprinkled onto the lower member prior to placing the plate, their dye lines move along the floor of the flovil and form a floor pattern, as in FIGURES 1, 4, and 5. If attached to the plate, a sharper set of lines is often obtained: the dye lines form a ceiling pattern a t first, then sink slightly to be carried along a t the higher velocities of lower levels in the flow space. Ceiling patterns are seen in FIGURES 2, 3 , 6, and 7. The writer invented the sandbed type of fluid flow analog in 1943, and proved it experimentally. That was the beginning of the modern work with the fluid flow analog. In 1948, the writer began the development of plaster techniques, and the devising of numerous forms of what the writer has called fluid mappers followed in rapid succession. Five papers (see references) have been published. Since these papers present many of the techniques and show many of the things that can be done with fluid mappers, the present paper will not attempt to include the details already published.