Today, hydraulic technology is widely available and benefits everyone who takes a shower, irrigates a garden, or puts out a fire. However, in the 17th and 18th centuries, steady water flow without the disturbance of pressure drops was a major breakthrough. In 1666, when the bucket fire brigade was still the best line of defense, the Great Fire of London destroyed nearly all of the city's dense wooden buildings. The disaster destroyed hundreds of thousands of homes and dozens of churches, highlighting the need for better firefighting methods and equipment.

The 1725 Newsham fire engine inspired the author to study the Windkessel effect, capturing the physics behind the enduring technique of steady water flow under pressure. Photo Credit: Image courtesy of Colonial Williamsburg Foundation

Fire innovation

A landmark advance was the invention of the "water-sucking worm," a leather tube attached to a hand-operated water pump. Later came the Windkessel, a chamber in the bottom of a wooden carriage that compressed air and continuously pumped water through a hose to create a steady stream of water.

Inspired by a fire engine from 1725, the author published an article in the American Journal of Physics published by AIP Press, analyzing the Windkessel effect in pressure chambers to capture the physics behind this widely used and enduring technology.

Author Trevor Lipscombe said: "There are many fascinating physics problems hidden in books and papers from centuries ago! Recently, we have been studying how to apply basic fluid mechanics to biological systems, and discovered a new method in a medical journal. A common description: the heart resembles a Windkessel, which begs the question: What exactly is a Windkessel? Following the lead, we found a description of Loftin's 'water-sucking worm' device, and found a life-saving application in Newsham's fire truck."

Physics and Fire Equipment

To determine which factors had the greatest impact on the Windkessel effect, the authors compared the initial conditions of the chamber, the rate at which the bucket fleet was filled (volume inflow), the length of time for pressure build-up, and the effect on the output flow rate.

"Physicists looking at Loftin's design or Newsham's fire truck want to sort out the basic science involved -- just because it's there. That's the fun part of physics. It's also an aspect of teaching," Lipscomb said. "Our paper builds a simple model that shows how a Newsham fire truck works. We go some way to answering the question, 'When am I going to use this thing?'"

Next, the authors plan to study the physiological Windkessel involved in the cardio-aortic system.

"Knowledge of Bernoulli's law, the ideal gas law and isothermal expansion were the three elements we used to build a model to explore how this device works," Lipscomb said. "But if we can understand the system better, we can study those important parameters and see how changing them will improve the device."

Compiled source: ScitechDaily