[HN Gopher] The hydraulic systems of the Alhambra Palace [video]
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       The hydraulic systems of the Alhambra Palace [video]
        
       Author : zeristor
       Score  : 139 points
       Date   : 2024-12-21 22:22 UTC (7 days ago)
        
 (HTM) web link (www.youtube.com)
 (TXT) w3m dump (www.youtube.com)
        
       | zeristor wrote:
       | I am particularly amazed by the water vortex drawing in air to
       | enable the water to rise higher.
        
         | Modified3019 wrote:
         | 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
        
         | twic wrote:
         | 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
        
           | petermcneeley wrote:
           | In the pdf you provided a significant portion of the water
           | appears to drain. So the energy equation might work out.
        
           | roenxi wrote:
           | 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.
        
           | stavros wrote:
           | 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).
        
           | zeristor wrote:
           | 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.
           | 
           | Vaersgo:
           | 
           | https://youtube.com/shorts/BkVUQQnfrDg
           | 
           | Ideally I'd like to see an experiment to explicitly confirm
           | it.
        
         | interloxia wrote:
         | 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 Garcia-Pulido, Luis Jose Journal of Islamic Studies,
         | Volume 27 (3) - Sep 1, 2016 https://www.deepdyve.com/lp/oxford-
         | university-press/the-mast...
        
       | russellbeattie wrote:
       | This is how toilets work as well.
        
       | dukeofdoom wrote:
       | 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.
        
       | theboywho wrote:
       | 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.
        
       | BrandoElFollito wrote:
       | 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.
        
         | DiscourseFan wrote:
         | There are no "normal" feeds on youtube, everything is
         | personalized, a product of the market and one of its benefits.
        
           | BrandoElFollito wrote:
           | 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.
        
       | trilomisk wrote:
       | 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 Lubeck, the Stiftsarmstollen in Salzburg
       | or the Wasserkunst of Augsburg.
        
       | omgJustTest wrote:
       | 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.
        
         | 73kl4453dz wrote:
         | I'd guess a continuous flow variation on
         | https://en.wikipedia.org/wiki/Heron%27s_fountain
        
       | elnatro wrote:
       | 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.
        
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