6,437km/h (4,000mph) to zero is going to be one hell of a stop.
My gut tells me that must be a couple of times the speed of sound...
Hyperloop lets you travel on a resonant acoustic wave?
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Re: Hyperloop lets you travel on a resonant acoustic wave?
#126,437km/h (4,000mph) to zero is going to be one hell of a stop.
Where do you get that figure from? The speed of sound is around 1000km/h,right? Still one hell of a stop but it might not be that fast, since basically its the air drag doing the braking.
Re: Hyperloop lets you travel on a resonant acoustic wave?
#13Re: Hyperloop lets you travel on a resonant acoustic wave?
#14Like most titles that end with a question mark - "no". Why would you use some kind of acoustic wave system over tried and true maglev?
Drag? And by the way - the title doesn't end in a question mark. ;)
It does on HN : P
Well, the acoustic idea wouldn't solve drag at all. The craft would still have to move through air.
Re: Hyperloop lets you travel on a resonant acoustic wave?
#15> it's not an evacuated tunnel Really? I thought it was already established that the Hyperloop is a vactrain ( http://en.wikipedia.org/wiki/Vactrain ). Using small cars (say, six passengers) accomplishes the "leaves when you arrive" and putting solar panels on top of the tunnel accomplishes the storing energy part. I wonder what the alternative would be and what its advantages over a vactrain would be.
Solar panels don't store energy. They only convert it.
Re: Hyperloop lets you travel on a resonant acoustic wave?
#16For someone who has taken nothing more than undergraduate physics as a requirement for my degree, can someone explain the benefits/risks of using an acoustic wave system over others? Has anyone previously looked at this sort of system for travel? If the wave were to be disrupted and these capsules come to a screeching halt, how fast of a deceleration are we talking about? Never more have I wanted to crack open my phy…
You point to an important omission in my scientific article! My gut just assumed the reason would be 'drag', specifically reducing it.
I guess the question is: would it require less energy to push capsules/cars through the tube with an acoustic wave than it would to force them through the tunnel e.g. with some sort of propulsion?
Re: Hyperloop lets you travel on a resonant acoustic wave?
#17If you can travel the world in 6hrs cheaply and if it goes well feel it should be developed everywhere possible http://www.techcrump.com/travelling-the-world-in-just-6-hrs-...
Re: Hyperloop lets you travel on a resonant acoustic wave?
#186,437km/h (4,000mph) to zero is going to be one hell of a stop.
My gut tells me that must be a couple of times the speed of sound...
Wolfram|Alpha gives 343.2 m/s (1236 km/h) at 20 °C and 1 atm.
http://www.wolframalpha.com/input/?i=speed+of+sound
Of course, in a closed system that isn't directly touching humans, it doesn't necessarily have to use those conditions. Still, I don't think you're going to get anywhere near 6400km/h.
Re: Hyperloop lets you travel on a resonant acoustic wave?
#19I can't figure out how the OP proposal differs from Charles Alexander's. Low frequency (long wavelength) waves travel around the tube at the speed of sound. By traveling at the same speed, and correctly choosing a point along the wavefront, one can take advantage of significantly reduced apparent drag. It's implicit in Alexander's suggestion that either (a) the total length of the loop is an integer multiple of the wavelength of the waves, so they are "resonant" in that sense, or (b) the envelope of the wave is much less than the length of the loop. (If neither (a) or (b) held, the wave could not be formed in the first place.)
So what distinction is OP making? That it's resonant, and so definitely (a) and not (b)? I think it would require a calculation of how fast the wave would disperse in the tube, which OP has not done.
Re: Hyperloop lets you travel on a resonant acoustic wave?
#20For someone who has taken nothing more than undergraduate physics as a requirement for my degree, can someone explain the benefits/risks of using an acoustic wave system over others? Has anyone previously looked at this sort of system for travel? If the wave were to be disrupted and these capsules come to a screeching halt, how fast of a deceleration are we talking about? Never more have I wanted to crack open my phy…
This depends entirely on the drag coefficient of the train car. If the engines on a supersonic jet cut off, it's essentially a rock traveling at the speed of sound through still air. I don't believe the acceleration is cataclysmic for the occupants (although probably jolting). Remember also that normal commercial gets travel at like 80% of the speed of sound, and they can easily handle a loss of engine power. (Although maybe typical engine cut-outs are more gradual than a suddenly ruptured hyperloop tunnel?)
So the train car need only have aerodynamics similar to an air plane in order to avoid bad stopping forces. An aerodynamic design makes sense anyways since you want to avoid drag.