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AUTO-EXPANSIVE FLOW
Citation:
Frick, W E. AUTO-EXPANSIVE FLOW. Presented at 2001: An Ocean Odyssey Meeting, Mar del Plata, Argentina, October 21-28, 2001.
Impact/Purpose:
Produce a computer model utilizing water transport estimates or real-time current-meter data to track the motion of contaminants from point and other sources, and to predict the concentration of pathogens or other pollutants at beach and other sensitive sites.
Description:
Physics suggests that the interplay of momentum, continuity, and geometry in outward radial flow must produce density and concomitant pressure reductions. In other words, this flow is intrinsically auto-expansive. It has been proposed that this process is the key to understanding turbulence as it will induce inflow and mixing in turbulent boundary layers. However, the theory contradicts the common assumption that velocity divergence term in the continuity relation may be neglected in modeling low Mach number turbulence. In other words, water is claimed to be dynamically incompressible. A rigorous compressible analysis of radial flow between two disks in water proves that the flow is predicted to be auto-expansive and that the divergence of velocity is significantly non-zero. The solution is compatible with the equation of state whereas the incompressible solution can be shown to be inconsistent with it and with the first law of thermodynamics. The work supports the basis for an auto-expansive model of turbulence.