Delikemmer Aqueduct: Example of inverted siphon

[guy]

 

The Delikemmer aqueduct is an impressive example of Roman engineering genius, utilizing the inverted siphon design. But first, some background information.

The Delikkemer Aqueduct is located near Patara, Turkey. This aqueduct was part of a 22.5 km (13.5 miles) water system that provided fresh water to the ancient Roman port city of Patara.

 

 

Instead of relying on arches to span the valley (see picture below), the Delikkemer Aqueduct utilized an inverted siphon system, enabling water to flow through pipes at high pressure, traversing the terrain without the need for elevated bridges. This method proved especially useful in rugged landscapes where constructing towering structures would have been impractical or unstable. Roman engineers perfected this technique, employing precisely cut and sealed stone or lead pipes to prevent leaks and withstand pressure shifts.

A traditional aqueduct with an arch:

Here's how the inverse siphon works:

An inverted siphon is a type of pipeline used to carry liquids, sewage, or water. Unlike a regular siphon, which relies on atmospheric pressure to move liquid up and over an obstacle, an inverted siphon forces liquid downward and then back up using gravity and pressure.

How it works: Entry point: The liquid enters the siphon at a higher elevation. Descent: It flows downward through a pipe, gaining velocity. Low point: At the lowest point, pressure builds due to the movement of the liquid. Gradual rise: The liquid is carried back up to the outlet, which is positioned lower than the entry point but higher than the lowest section of the siphon. Gravity and pressure continue to drive the flow toward its final destination.

Through the use of the inverted siphon engineering, water was allowed to flow between hills both downhill and uphill without the need for pumps, through gravitational forces and pressure.

 

Picture depicting the inverted siphon with the traditional arched structures to carry water:

 

The use of the inverted siphon could be especially important in earthquake-prone regions, such as Turkey.

 

A good summary article of the Delikemmer Aqueduct (and source of most of the pictures of the Delikkemer Aqueduct)

Roman Aqueduct Engineering: The Delikkemer Inverted Siphon Near Patara Along the Lycian Way – Electrum Magazine

 

Note: In Turkish “delik” means hollow and “kemer” means arc or belt. So Delikkemer means hollow arc or belt.

 

A short video describing an inverted siphon:

 

Edited Saturday at 08:35 PM by guy

[guidoLaMoto]

-not sure "inverted siphon" is a good term.....A siphon requires a bit of energy input (Eg- actively sucking fluid up a tube to empty a higher reservoir over the lip of it's container into a lower basin, or powering a roller coaster train up that first big hill....once accomplished, gravity takes over). .....As long as the source reservoir is higher than the destination reservoir and there are no higher points along the way, the water will flow......For gravity powered systems, PE + KE = a constant.

The Romans could have avoided building the elevated, arched aquaducts if they had adequate piping to contain the very rapid, high pressure flow along the low points of the course. (You'd think stone & cement joints would have done it.)...Maybe they used the elevated sections to avoid tedious tunneling or to avoid blocking traffic with extensive solid walls and save on materials.

The engineering physics of aquaducts is pretty simple. The amazing part is the sheer audacity of the first guys (Appius Claudius Caecus & Caius Plautius 312 BC) to think they could bring water from 10 miles away to Rome.

[guy]

9 hours ago, guidoLaMoto said:

The engineering physics of aquaducts is pretty simple.

Although the physics of aqueducts may appear straightforward, the actual implementation is very unusual in the ancient world. The Persians, Greeks, and even the Maya and Incas had developed extensive water storage and transport systems. 
 

Several Roman innovations, however, allowed more sophisticated engineering projects. Roman concrete allowed for durable structures. The use of a waterproof coating (opus signinum) prevented water leakage, allowing water to travel at a high enough velocity and adequate pressure to create the inverted siphon described above. And of course, the large-scale Roman arch system allowed the transport of water over rugged terrain.

 

https://www.mdpi.com/2073-4441/14/1/28

Edited 2 hours ago by guy