Is it possible?. I just know it is possible in liquids and gases, but what would be the (structural) effect of a supersonic wave in a solid?. And how can we generate it?
I'm sure I musta learned that at one time. I gotta get my arms around it again.LURCH said:Supersonic waves are generated by high explosives. In fact, I believe that is the definition in between "explosive" and "high explosives". I suppose the shock waves used to pierce armored vehicles or implode condemned buildings could be considered "a wave moving at supersonic speed through a solid", since the force of this pressure wave travels through the metal at a speed greater than the speed of sound through that same metal.
The nail is analogous to the plane - the shock wave doesn't travel through the plane. I guess a hammer hitting a nail at supersonic speed would simply crush the nail a la Lurch's explanation of high explosives.So the new situation would be a nail being hit and going inside the solid at supersonic speed. I mean it goes with a velocity faster than the sound one of the solid. It would be similar to a supersonic wing inside a fluid. Does it exists a shock wave inside the solid, Mach cone...etc?.
russ_watters said:The nail is analogous to the plane - the shock wave doesn't travel through the plane. I guess a hammer hitting a nail at supersonic speed would simply crush the nail a la Lurch's explanation of high explosives.
Well, ok, but that wouldn't make it supersonic, would it?Nenad said:the reason the sonic wave speeds up is because it travels faster in the solid. I should have said that you emmit a sound from a gas towards a solid. Lets say the sound travels at 300m/s. When the sound hits the solid, the molecules start vibrationg with same oscilations as the gas molecules, but the gas molecules are a lot further appart, making the sound wave go faster in the solid since its molecules are so tightly packed in.
If that was what you were referring to, it certainly was NOT what you said!Clausius2 said:Well guys, I was just referring to some proyectile penetrating supersonically (i.e. v>>c(solid)) into a solid. What is the difference with an aeroplane flying supersonically in the air?.
Yes, of course. There is a more extensive literature on shock waves (which travel at the speed of sound) in solids than in air.In both mediums there will be elastic or plastic deformations transported via waves. The problem here is: will a solid's particle be deformed if the source of deformation (proyectile) goes faster than elastic wave speed?. Surely it will be deformed, but not in the classical way. My question is if all physical process involved with discontinuities (shock waves) in fluids are extensible for solids. (I'm sure it will be with another equations).
Because "sound velocity" is DEFINED as the speed of propagation of deformations. I don't see why you would think that light velocity would have anything to do with it. As for "light velocity does not appear in the Wave Equation", the natural velocity of waves in the solid appears in the wave equation- that is, by definition, the "speed of sound" in that solid. The speed of light is the natural speed of electromagnetic waves in vacuum and has nothing to do with wave in solids.The other question was: what is the role of light velocity in the propagation of deformations?. We always talk about sound velocity, but the real question is: Is it not curious that light velocity does not appear in the Wave Equation? (for elastic waves in a solid).
HallsofIvy said:If that was what you were referring to, it certainly was NOT what you said!
You specifically asked about a wave traveling faster than the speed of sound in the solid. That is impossible by definition. It is, of course, possible for an object to move through a solid faster than the speed of sound (i.e. the natural wave speed) in that solid.
I don't see why you would think that light velocity would have anything to do with it. The speed of light is the natural speed of electromagnetic waves in vacuum and has nothing to do with wave in solids.