Any realistic ideas for a suction-based weapon?

Question

I’ve been looking for real-life examples of suction-based weapons or weapons that work like a vacuum, violently sucking up the surrounding matter, but my search hasn’t generated any decent results. The closest thing I found were cases of swimmers being eviscerated to death by high-pressured pool drains, sucking their internal organs out via suction.

I want something that operates like that but covers a bigger radius. I imagine this weapon would have to be pretty large in size (thinking maybe the size of a tank) in order to suck things into it like a vortex, but I would appreciate it if someone more knowledgeable in physics/science could help assist me with how exactly this would be designed.

The way I visualize it is either something like a giant circular panel/drain on the floor that, once activated, violently sucks up everything in the room surrounding it, or something like that orb-shaped pod in the movie The Fly, but obviously much larger in scale. However, I am open to any alternative ideas for how this could be designed as long as it’s “realistic” (obviously, most fiction requires you to suspend your disbelief, but I want something that could at least be plausible from a historical-fiction perspective, like the Demon’s Core experiment or Chernobyl)

Something like this for reference:

EDIT: For context, the story I’m writing is about a fake physicist w/ forged credentials who is mocked by the scientific community for their bizarre theories about generating and weaponizing black holes for military use. They are dubbed as a “wannabe sci-fi writer” and “pseudoscientist.” In an attempt to prove them wrong, they try building an actual black hole generator which they can present to the scientists, who are invited to come to the lab for a demonstration. During the demonstration, one of the scientists volunteers to go into the testing chamber with the machine. The testing chamber door is shut and sealed, and a button is pressed, activating the 747 jet engine beneath the floor. The victim, along with a few objects in the room are violently sucked into the vessel of the machine and eviscerated as if by a pool drain. The audience scrambles to alert security, while the creator insists the person’s body was sucked into a different dimension by a vortex. Police come, tear up the floor to find a reservoir of ground up matter (and organs), and promptly arrest the machine’s creator. In reality, all they really built was just a giant high-tech vacuum, but it’s their delusional belief that they created a real black hole that has them sent to a mental asylum as opposed to a prison

As far as the design of the testing chamber (for those wondering the scale/radius), I imagine the room to be dome shaped, going 12’ in each direction from the center, with the part of the machine above the floor taking up about half of the floor’s 24-foot diameter. As for the height of the machine, the diameter of the vessel opening, etc. I’ll leave that up to you guys to do the math on

Answer 1

Suction Weapons as described are not all that effective

The only reason a pool drain can kill like that is because you have the weight of all that water behind them. In general, a 1 atmosphere of pressure difference is not enough to kill a person and the actual pressure gradient caused by a suction means you have a pretty short range on what ever weapon you design.

Since this question is tagged with "weapon-mass-destruction", I would have to say that weaponized air suckers would fail to qualify no matter how well you designed it.

That said, there is one kind of real world weapon that uses suction in a different way that is incredibly deadly...

Thermobaric Bombs (AKA: Vacuum Bombs)

While most bombs contain their own source of oxygen spending up to 75% of the bomb's mass on oxidizing agents, thermobaric bombs are almost entirely fuel. The most common type of thermobaric bomb works by first detonating a small bomb to spread a hot cloud of fuel over a large area until it spreads out enough to use the atmosphere as the oxidizer. Apart from making a larger, overall more deadly blast, thermobaric bombs create secondary damage by sucking all the air in from around the blast. So even if you are outside of the actual blast radius, this vacuum is enough to suck the air out of your lungs, burst capillaries, pop ear-drums, etc.

... but more important than what the fireball pulls into it is what forces pull on the fireball itself. As the air burns, any near by buildings, pillboxes, trenches, caves, etc. will have the air all burned out of them. This leaves behind a vacuum in the fortification that actually pulls the cloud of burning air down into it allowing flames to violently spread to fill spaces that would not otherwise be reached by an equally powerful self-oxidizing explosive.

Answer 2

One of the most common misconceptions about vacuums is that they create some sort of sucking force. This is exactly wrong. A vacuum is simply a low pressure area. The force that acts on the air, water or what have you into the low pressure area comes entirely from the pressure of the air/water/whatever around it, not from the vacuum itself.

Since all of the force comes from the surrounding environment, the 'strength' of the vacuum itself is limited to the prevailing pressure. Once you reach zero pressure - or as close as you can achieve - you're at your absolute limit of potential power. The total force at the aperture is then the aperture's area multiplied by the environmental pressure... with an additional limit based on the strength of the pump that is maintaining the vacuum. When the aperture is sealed there's a brief surge of additional force based on the inertia of the in-rushing material, but this will drop off rapidly as the external pressure stabilizes.

In order to actually capture a target you're going to need some way to channel the in-flowing material in a way that the sheer motion of material carries the target along with it. This is complicated by the fact that the environment applies pressure from all directions. If you can achieve a high enough flow you could potentially use a tunnel or some sort of secondary aperture - a doorway for instance - to focus the effect. Not very useful for an open area however. Even the Vacuum Tank suggestion would have a very limited range. You'd have to basically drive the tank right up to your target, or get something on the other side of the target to drive them towards your intake.

If you manage to channel the air into the target zone through long tunnels you might be able to prolong the seal shock through sheer inertia, but it'll take time - and a significant mass of moved air - for this to be enough to damage the target. Again, once the pressure equalizes, the remaining force is environmental pressure times aperture size. That will need to be high enough to prevent the target from simply pushing off from the trap.

Human bodies have an internal pressure that balances against the environmental pressure. This means that if you can hold the person in place for long enough the surface exposed to the vacuum will eventually be pushed out of shape. Water will boil, dessicating the surface and reducing its integrity. The skin will crack and break, blood in the immediate area will boil, blood and the soft parts of the body - fat, muscle, organs - will be pushed into the low pressure area. It's not going to be quick, but if you catch them in the right place it will kill them painfully... if they're not wearing sturdy clothing anyway. Denim will prolong the process significantly, Kevlar will probably seal the aperture and completely bear the brunt of the pressure differential - leaving the target trapped but not dying.

Of course if you've managed to catch them by the head... well, it's all over in a minute or so, so at least they won't suffer quite so much. That's what you get for sticking your head in a trap though, am I right?

Answer 3

The Jet engine Suction Tank

If you aren't worried about being practical, you could create a suction weapon by putting a high bypass jet engine on top of a tank. This would have a suction range of around 10-20 feet, which would be smaller than the length of the tank itself. The exhaust would be dangerous up to around a hundred feet- a more effective weapon than the suction, but it's fine that we aren't solving for effectiveness here. The victim diverter grid would need to be extremely well built, and would comprise the majority of the weight of the system: this is why it needs to be carried on a tank chassis and not just a truck.

Suction Math

Basically, because of a quirk of physics, suction past a certain power level only depends on the hole size: air will be going at the speed of sound at the opening, and will drop in speed with the square of distance. As a result, the air will always be going ~150 mph at around 2 hole diameters from the suction point, or ~70 mph at 3 hole diameters. Force is proportional to speed squared, so force drops with the fourth power of distance. This defines the effective range -- you need around 100 mph to throw a person. This fourth power relationship means that suction will develop suddenly as you get close: airport workers report that the suction from a jet engine goes from nothing to terrifying with a single step towards a jet engine, even when ~15 feet away.

Answer 4

The BugZooka is such a weapon!

source

• BugZooka is a fast, simple, and clean way to rid bugs from your home
• The innovative and light weight new BugZooka lets you keep your distance and avoid bug squish and splatter
• It's unique patent pending design creates 10X the instant suction of heavy battery powered devices
• Bugs are sucked instantly into a removable catch tube with the simple press of a button

You mentioned something "obviously much larger in scale" but the reason why was not obvious. I suppose you could scale up BugZooka to a crew manned weapon of sorts, taking on really big bugs, mice, birds and maybe small dogs.

Answer 5

Suction weapons exist in nature, octopuses and squids use them (suckers).

Problems

You seem to be interested in something that acts at range, and in air. These seem like problems. Firstly, as others have said, the air pressure (1 atmosphere on Earth) sets the upper limit to how hard you can ever suck with air. In this extreme case you extort zero pressure (or basically zero) so that the full 1 atmosphere of air on the other side of the target has nothing to cancel it. But that 1 atmosphere is the limit. Secondly, range. If the target is a ways away then you are going to use an awful lot of your energy supply sucking up air, and only a small % of your energy on hurting the enemy.

Possible Solution

Depending on how science fiction your setting is you could use Tractor Beams to overcome these shortcomings. These fictional devices, in Star Wars for example, pull a thing towards you (which is essentially suction, there would be plenty of wind for example). Maybe they work with artificial gravity. If you had a beam that pulled things along a cylinder (or maybe a slightly expanding cone) very strongly towards you (maybe pulling you back towards them with the recoil), then you could certainly weaponize that. Having a small part of my body accelerated away at hundreds of gravities could certainly cause injury, maybe my heart and the surrounding tissue being ripped out.

Answer 6

Make a hurricane

While all other answers were correct in a sense that a vacuum device have to rely on surrounding atmosphere to do any actual damage, they did not took into account factor of inertia. Make air move fast enough and it'll create large force (dynamic pressure). An atmospheric pressure difference of merely ~10% over a country-sized region is a force that drives all hurricanes in our planet. You just need to keep removing the a lot of air fast enough for long enough time. With unlimited access to vacuum and under ideal conditions you can accelerate air on Earth to a speed of sqrt(2*P/rho)=sqrt(2e+5 pa/1.2 kg/m3) ~= 400 m/s or over 900 miles/hour. That's a supersonic flow and it's way more powerful than a wind in even the most powerful hurricane. But to reach this in open-air, you'll need to rapidly remove all air from a slice across the whole planet. A more realistic device that'll suck air in a "hole" with diameter, say, of 50 km should be enough to create hurricane, though.

Planets with dense atmosphere

Atmospheric density on some planets is much higher than on Earth, significantly simplifying design of a suction-based weapons. However this apply to natural phenomena too, so people on that hypothetical planet should be already capable to deal with ultra-strong wings anyway. But this might mean that they would be living underground and suction-based weapons might be fairly strong when used in tunnels filled with dense atmosphere.

Asphyxiate your enemies

If we're talking about closed environments like a space station, denying access to oxygen can make an efficient weapon. Consider a dystopian society where you have to pay an air fee to government in order to breathe. If you are missing your payments for too long or government doesn't like you it can suck air out of your apartment. This kind of weapons can be non-lethal too, since it takes just ~10 seconds for person to lose conscience in vacuum, but several minutes to die. This can be used as an efficient tool for police raids or for riot control.

Answer 7

As other answers stated suction would not be very effective. But only if you want to use it into thin air. In dense water it is quite different, suction is used by a lot of fishes to catch their prey, a mouth that extends and widens to pull in the surrounding water with whatever is in there is quite common. Your weapon could be a trap set underwater near some important installations to protect them from saboteurs or just too curious scuba divers.