In this experiment a radial temperature gradient will be created using a metal ice bath
placed inside the tank. The differential heating pattern created in the tank is analogous
to the differential heating pattern created on the earth where there is warming at the
equator and cooling at the poles. The ice bath represents the poles and moving radially
outwards is analogous to moving towards the equator. Eddy formation is characteristic of
the Mid-lattitudes and is a source of heat transport in this region.
To run this experiment
1. Place the white circular sheet on the bottom of the tank
2. Using the clear plastic sheet, form a cylinder around the circular white sheet
3. Fill the tank to 12 cm with water
4. Fill the metal cylinder with ice and water
5. Put the PVC pipe weight in the cylinder to stabilize it
6. Place the cylinder towards the center inside the tank
7. Set the period to a desired rotation (faster = smaller more unstable eddies)
8. Allow a circulation to develop for about 20 minutes
9. Inject red dye into one side of the tank
10. Inject blue dye into the water opposite to the red dye
Trial 1: Rate per rotation = 7 seconds
Trial 1: Rate per rotation = 16 seconds
Trial 3: Rate per rotation = 20 seconds
There are two types of motions happening in the tank. The temperature gradient induces a meridional flow
where cooler water at the bottom of the tank is swept outwards (this can be observed by noting the streaks
at the bottom of the tank), and warmer water in the surface layer is swept inwards towards the metal
cylinder. The circumferential flow in the tank, also known as the jet, becomes unstable at high periods
of rotation. The faster rotation of the tank corresponds to a stronger coriolis force at the higher
lattitudes on the earth. The instability of the jet at higher lattiudes, or our case a faster rotating
tank, is what produces eddies.
