A quiescent fluid at temperature T3 is confined between two vertical parallel plates. While plate 1 is kept at temperature T1 and plate 2 is maintained at temperature T2, a velocity profile between the plates, as shown in the figure below, is generated due to heat transfer. Which one of the following options shows the correct relations among T1, T2, and T3?
Show Hint
Match the rising and sinking flow directions shown in the figure to which plate is hotter or colder than the fluid.
The picture is a standard natural convection cell between two plates at different temperatures, with the fluid itself sitting at an in between temperature T3.
T1 > T3 and T3 > T2: matches the figure. Warm fluid rises next to plate 1 (so plate 1 is hotter than the bulk), and fluid sinks next to plate 2 (so plate 2 is cooler than the bulk).
T1 > T3 and T3 < T2: wrong, this needs fluid to sink next to a hotter plate 2, which goes against buoyancy.
T1 < T3 and T3 < T2: wrong, this would make fluid sink next to plate 1, where the figure actually shows it rising.
T1 < T3 and T3 > T2: wrong for the same reason, the direction of motion at both plates is reversed from the figure.
Only option (A) agrees with the rising flow at plate 1 and the sinking flow at plate 2, so it is the correct choice.
