The hydraulic systems of the Alhambra Palace [video] | Hacker News Reader

The hydraulic systems of the Alhambra Palace [video]

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Alhambra comes from the Moroccan Arabic word "Alhamra" which means The Red, it shares many engineering similarities with what was practiced at the time in what is today considered Morocco, some examples include:

- The Kasbah of Moulay Ismail in Meknes, a parallel to the Alhambra’s engineering sophistication, particularly in its hydraulic systems.

- Khettara Networks: Underground water channels designed to transport water down slopes without active pumping with gravity-fed systems that tap into aquifers, there are extensive networks of these particularly around Marrakech and southern regions.

This is really cool video. This Palace is also significant if you are into garden design. As it holds a kind of best in its class of Arabic/Islamic gardens. You would be surprised how much rich people care about their gardens. So this one is an inspiration. And not just to the leather panted garden designers. But lots of people that visit this palace get inspired by the graden there.

I am particularly amazed by the water vortex drawing in air to enable the water to rise higher.

Yep, saw this video a while ago and came here to say that there’s multiple clever systems in place, but that bit’s definitely worth a watch. It’s at about ~7:30

I'm not sure i believe that bit. If you can lift a flow of water from one level to a higher level without an input of energy, you have a perpetual motion machine. And those aren't allowed.

I assume that what happened here is that some fraction of the input flow was drained to a lower level, and the liberated potential energy captured and used to lift the remaining fraction to a higher level. That's not what's shown in the video, though.

There's a description starting on page 369 here, although it's not completely clear how it works (the author is an archaeologist, not an engineer!): https://sci-hub.se/10.1093/jis/etw016

Subsequent prior art (IYSWIM) is the hydraulic ram, which does this a different way: https://en.wikipedia.org/wiki/Hydraulic_ram

In the pdf you provided a significant portion of the water appears to drain. So the energy equation might work out.

Indeed. Fascinating puzzle. Without an external source of energy there must be a volume of water leaving the system that doesn't make it to the higher level. If it was possible to partition the water and the energy but not with the same partition (ie, 40% of the water gets 80% of the energy, 60% of the water the other 20%) then the system would be thermodynamically legal. So maybe the vortex was to create a high- and low- pressure mass of water.

This mechanism is ingenious in the best meaning of the word.

I wonder if the extra energy is the kinetic energy (the water rushes into the cistern to create the vortex, but then is still when it's raised).

The first video I saw was a YouTube short purely on this, I had thought it was just taken from this main video.

My understanding was that the water was aerated, and so less dense meaning it could rise higher.

Værsgo:

https://youtube.com/shorts/BkVUQQnfrDg

Ideally I’d like to see an experiment to explicitly confirm it.

The vortex might be a variation of a trompe, a water-powered air compressor. The compressed air is in turn used as an airlift pump.

new to me: https://en.wikipedia.org/wiki/Trompe

https://en.wikipedia.org/wiki/Airlift_pump

edit: the text version of the video refers a study that I don't have access to.

https://primalnebula.com/the-engineering-of-the-alhambras-wa...

The Mastery in Hydraulic Techniques for Water Supply at the Alhambra García-Pulido, Luis José Journal of Islamic Studies, Volume 27 (3) – Sep 1, 2016 https://www.deepdyve.com/lp/oxford-university-press/the-mast...

It would appear the description of the last water feature in the video "07:38 Gravity Defying Medieval Technology"

is either under-diagramed or under-explained.

Does someone have a reference for this? I am finding some references on wiki about hydrorams or airlift pumps... which make much more sense.

I'd guess a continuous flow variation on https://en.wikipedia.org/wiki/Heron%27s_fountain

Funnily enough, the “Alhambra Palace” is a hotel that opened at the beginning of the XX century, while the “Alhambra” is the monument from the medieval age.

The Alhambra is not a palace, well it was actually a castle (the meaning of Alhambra is “red castle”). It had a palace inside but it was a fortification mainly.

Of course as Boabdil surrended the city of Granada to the Catholic Monarchs (Isabel and Fernando) in 1492, the Nazari dinasty did not enjoyed the palace many years.

> (the meaning of Alhambra is “red castle”)

I'll have to correct that.

I) Linguistically :

Al-Hamraa [AR: الحمراء] is just the definite feminine noun for "the red one" the definite male noun being Al-Ahmar [الأحمر]. There's no mention of castle here, but, as usual in Arabic, there might be a case of abbreviation by omission.

The full noun of the complex is one of these, which are all used: 1. Al-Qalâatu Al-Hamraa [القلعة الحمراء] (translated as: The red castle) 2. Qasr Al-Hamraa [قصر الحمراء] (translated as: The palace of the red one [fem]) 4. Qalâat Bani-l-Ahmar [قلعة بني الأحمر] (translated as: The castle of the sons of Al-Ahmar) 3. Qasr Bani-l-Ahmar [قصر بني الأحمر] (translated as: The palace of the sons of Al-Ahmar)

The latter two might be the originals, since the complex is named after the other name of the Nasrids, "Bani Al-Ahmar" (sons of the red one [male]). So, both Palace and Castle are used interchangeably, so the name here holds no evidence if it's a castle or a palace, nor should it do, which brings us to ...

II) Epistemologically :

The Alhambra complex is a fortification surrounding many quarters, gardens and buildings; some of which were added later. The most important and central parts are the Nasrid royal palaces (yes there's many). One could say that the other parts were initially built and made to serve this central one.

I would argue that the correct description for Al-Hambra is "citadel", even though the Al-Qasaba garrison within it usually takes that definition.

Anyway, I believe the meaning lies not in words, but in context. I encourage anyone who's able, to go visit Al-Hambra and similar "Palaces".

This is how toilets work as well.

I saw this as well in my youtube recommendations and this post made me wonder how many people have a similar recommendation feed.

I watch YouTube for my interests/hobbies, so this does not reflect a "normal" profile (I think). My feed is full of cooking, paintings restoration, coding, action movies, history of the middle ages in western Europe, hoof trimming (I saw a real cow close twice in my life) etc.

I was always wondering if there are people wil a similar feed, but never found research on that.

There are no "normal" feeds on youtube, everything is personalized, a product of the market and one of its benefits.

Yes, I know, but it would be interesting (at least for me) to know how interests of people are clustered and interconnected - and how much of outliner one is.

Only 5 seconds into the video they show plate amor in the year 1236. This is a disappointing start, I kinda like the rest, though. They have a wide reach and Alhambra is a good example to present a fascinating topic to a wide audience. It would have been great, though, to give more historical context.

Water management systems in the middle ages in general were incredible sophisticated and widespread. Hydropower was in use for basically everything. There are dozens of examples of castle wells more than a hundred meters deep, all cities in the late middle ages had systems of wells and channels, often cooperatively organized. Impressive examples include the water supply for breweries in Lübeck, the Stiftsarmstollen in Salzburg or the Wasserkunst of Augsburg.

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