• glorkon@lemmy.world
    link
    fedilink
    English
    arrow-up
    2
    ·
    edit-2
    23 hours ago

    Let’s do it:

    The phenomenon that causes divers to be trapped is called differential pressure, or Delta P. It requires surprisingly little Delta P to trap divers in such a way that they can’t free themselves.

    The formula is simple: F=Δp⋅A

    Δp = Differential pressure, A = the area the differential pressure acts on, in our case the cross sectional area of the pipe.

    Example:

    30 cm pipe => A = π⋅(0,15)² m²

    Delta P only (!!!) 0.1 bar (= 10 kPa).

    F = 10,000 Pa ⋅ 0.07 m² ≈ 700 N. This equals roughly 71 kg of weight.

    Now, let’s try this with the numbers above. Unfortunately, we don’t know the diameter of the pipe so let’s again assume 30 cm:

    Δp = 21.375 - 14.7 psi = 6.675 psi ≈ 0.46 bar = 46 kPA

    F = 46,000 Pa ⋅ 0.07 m² ≈ 3250 N.

    => You would be sucked to this pipe opening with a force of roughly 330 kg. In other words, you’re fucked.

    For fun, let’s assume a 50 cm diameter pipe:

    F = 46,000 Pa ⋅ 0.196 m² ≈ 9020 N.

    This equals roughly 920 kg of weight.

    => There is absolutely no escape here and I think it’s safe to assume the diver would be sucked through that pipe.

    And finally, to answer your question (I’ll skip the math here), a 10 cm diameter pipe with the same Delta P would mean 37 kg of weight. I think it would be possible to escape in this scenario, but it’ll not be effortless.

    • prenatal_confusion@feddit.org
      link
      fedilink
      English
      arrow-up
      1
      ·
      14 hours ago

      Ah, I didn’t make myself clear. I am and was absolutely convinced that you can’t free yourself once “plugged” unless very lucky. I was thinking about the bring sucked into pieces aspect. But it’s the same calculation I guess. How much force can human body structure take? I think 330kg static pressure wouldn’t rip you apart but when there is some movement involved there is some extra momentum. I think that could work. Or we increase the area. But then we don’t have the nice space movie effect of being sucked through a small slot.

      Edit and also j didn’t read the whole comment. Especially the block where you talked about the part that I just repeated. Sorry and thanks for your work :)