Final answer:
The HVE operates by moving a large volume of air into the vacuum hose at lower pressure, creating strong suction based on the principles of fluid dynamics where higher velocity leads to lower pressure.
Step-by-step explanation:
The HVE (High Volume Evacuator) is able to take up water and debris because a large volume of air is moved into the vacuum hose at a lower pressure to create a strong suction. This is based on principles of fluid dynamics, where the pressure and velocity of a fluid are inversely related — as described by Bernoulli's principle. The pressure inside the hose is greater than in the nozzle because velocity is higher in the nozzle, hence causing the pressure to drop according to this principle. Since the nozzle releases into the atmosphere, the pressure P2 in the nozzle must be atmospheric. In systems like HVEs, differences in air pressure are what enable them to pick up materials effectively.