Final answer:
Local building codes ultimately determine the required distance between the top of a chimney and operable windows. In chimney design, Bernoulli's principle aids in the effective expulsion of gases using T-shaped pipes. Additionally, there are physical limits to how high an entrainment device can raise a fluid.
Step-by-step explanation:
The question regarding the radius within which the top of a chimney must be above any operable window is typically answered by local building codes and regulations, which dictate the required distance for safety and health reasons, often taking into account factors like the prevention of smoke re-entrance into the home.
Additionally, the design of some chimney pipes, such as those with a T-shape and a crosspiece, leverages Bernoulli's principle to aid in the drawing up of gases. This works because as the breeze passes over the crosspiece, the speed of the air increases, leading to a decrease in pressure according to Bernoulli's principle. This low pressure helps to pull the gases up the chimney more effectively.
Moreover, there is a physical limit to the height to which an entrainment device can raise a fluid, which depends on factors like the fluid's density, the velocity of the entraining fluid, and the geometry of the device.