Final answer:
The Bernoulli effect describes how fluid speed increases and pressure decreases in constricted areas, such as chimney pipes or airplane wings. This principle also explains the lifting of roofs in cyclones and the operation of Venturi constructions in fluid dynamics.
Step-by-step explanation:
The Venturi, or Bernoulli effect, is a principle in physics that explains how the speed of a fluid increases as it passes through a constricted section of a pipe or over a wing, leading to a decrease in pressure. When wind flows over a mountain peak, it accelerates as the area through which it flows narrows, similarly to how air speeds up when flowing through a Venturi tube. This increase in speed at the contraction leads to a reduction in pressure according to Bernoulli's principle.
Chimney pipes often employ a T-shape to make use of this effect. The crosspiece on top alters the air flow, accelerating it and thereby reducing the pressure above the chimney, which helps to draw gases up from below. Airplanes take off into the wind to benefit from higher relative airspeed over their wings at take-off, leading to more lift. Bernoulli's principle can also explain why roofs lift off during a cyclone - the fast-moving air on top creates a low-pressure area, causing the roof to be pushed upwards by the higher indoor pressure.
In the case of a fluid moving through a Venturi construction, Bernoulli's equation can be used to show that the fluid's velocity increases as it passes through a constriction and the diameter decreases. The speed of the flowing fluid is inversely related to the cross-sectional area of the pipe. Hence, the narrower the constriction, the faster the fluid must flow to maintain mass conservation.