This experiment is an important building block in our effort to model flow in the Farnsworth House. We believe that the Rayleigh number in the house when the heat is on may be roughly comparable to the quantity found below, and thus it is of central importance to develop skill in using Phoenics for accurate modeling under these conditions. It should be noted that the Farnsworth House is inherently more complex than the hot box, because the heat source in the house is on the bottom rather than along one of the vertical walls. When the heat flows in and out of the walls only, the rotational direction of the convective forces is clearly defined: up the hot wall, down the cold wall. When the floor is hot and the cieling (and walls) are cold, then the flow may be initially unstable.
Physically, the box is 2.5m high (y-axis) and 0.5m wide (x-axis). The z-axis is considered a symmetry plane and the problem is modeled two-dimensionally. The left (x=0) wall is at +22.9 deg C and the right (x=0.5) wall is at -22.9 deg C. All other surfaces are assumed adiabatic. The walls are smooth, and friction is modeled with a log-law approximation. Note: any figures with x >> y are vertical pictures viewed on their side; they should be rotated 90 degrees clockwise to correct.