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The most dramatic eddy sampled using the particle-tracking software, visible in part on bottom left-hand side of figure 2.2, is quite telling apropos to the "heat flux" within the tank. Despite rotation throughout the eddies towards and away from the center, the thermal gradient within the tank suggests that heat should have a net movement towards the center. A side view of the same graph focused on the most intense eddy illustrates the "winds" embedded within this rotating swirl of fluid; positive velocities are towards the center, with negative velocities away from the center. At first a chaotic scatter of points demarcating velocities at given points (with the x and y axes marking position, with the z axis reserved for velocity), a blue parallelogram has been drawn into Figure 2.3, along with a yellow line illustrating the zero level of velocity from the graph's perspective. One can clearly note that the area of the parallelogram containing data points above the zero line is far greater than below the line, indicating a net movement towards, and thus a heat flux in the direction of, the center. This is exactly what is expected in the atmosphere, and what our group observed in the tank,.
Figure 2.3:
In addition, our group was able to note at least half a dozen eddies embedded within our fluid visually using food coloring and dye; the red was placed on the outside of the tank, with blue inside the tank. As mixing occurred, the dyes were dragged along with the rotating fluid, and as such the patterns of warm and cold water were able to be shown. Figure 2.4 depicts these illustrative markings:
Figure 2.4:
Thinking back to Project 2, an investigation into the thermal wind balance and formation of the jet stream, one could in essence convert the motion of particles throughout the fluid into a vector field; in doing so, there would exist one continuous path that completely encircles the central cold-dome within the tank. This would indicate the jet stream, with the serpentine pattern waving towards and away from the center and ensnared within eddies and vortices rotating around in the larger body of fluid. One may note that the blue and red eddies rotate in opposite directions, much as is the case within the atmosphere due to regimes of higher and lower pressure.
One item of note in figure 2.1 is that the temperature at each sensor, though subject to slight oscillations due to eddies, slowly decrease with time somewhat uniformly throughout the fluid. This is to be expected, as the thermal energy contained within the relatively warmer is transferred and over time reduced as it in turn warms the ice to above melting point. Thus, though the temperature of the ice/water solution remains at 32 degrees, the increased thermal energy is instead utilized in the form of latent heat, responsible for the change in phase of the liquid. As such, the amount of energy needed to fully melt the block of ice placed in the center should be equal to product of the ice's mass and the specific heat of fusion. Therefore, considering that 771.4 grams of ice were used in the experiment, one would anticipate that roughly 258,000 Joules of energy would be necessary complete this thermal transaction. Spread over a period of approximately 4,000 seconds, the result is in effect the energy required to power a 64-Watt light bulb, and may be practically thought of as a "negative light bulb" placed in the center of the tank according to Dr. John Marshall.