What is Shock wave: Definition and 53 Discussions

In physics, a shock wave (also spelled shockwave), or shock, is a type of propagating disturbance that moves faster than the local speed of sound in the medium. Like an ordinary wave, a shock wave carries energy and can propagate through a medium but is characterized by an abrupt, nearly discontinuous, change in pressure, temperature, and density of the medium.For the purpose of comparison, in supersonic flows, additional increased expansion may be achieved through an expansion fan, also known as a Prandtl–Meyer expansion fan. The accompanying expansion wave may approach and eventually collide and recombine with the shock wave, creating a process of destructive interference. The sonic boom associated with the passage of a supersonic aircraft is a type of sound wave produced by constructive interference.
Unlike solitons (another kind of nonlinear wave), the energy and speed of a shock wave alone dissipates relatively quickly with distance.
When a shock wave passes through matter, energy is preserved but entropy increases. This change in the matter's properties manifests itself as a decrease in the energy which can be extracted as work, and as a drag force on supersonic objects; shock waves are strongly irreversible processes.

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  1. G

    I Conservation of linear momentum in RH relations

    I am trying to follow a derivation of the Rankine-Hugoniot equations in a paper by Peter Krehl titled: The classical Rankine-Hugoniot jump conditions, an important cornerstone of modern shock wave physics: ideal assumptions vs. reality This paper talks about the RH equations which relate...
  2. S

    I How fast does a blastwave travel?

    I read on Wikipedia , Encyclopedia Britannica and threads on this forum that shockwaves travel faster than the speed of sound, but when I watched this youTube video, it appears that even a shockwave from a C4 detonation travels at about the speed of sound. I have extracted a couple of frames...
  3. DifferentialGalois

    Exploring Shock Waves: A Mathematical Analysis

    the attempted is the above ex. i needa justify why and figure out the reason behind those relevant equations.
  4. agnimusayoti

    What is the mathematical model for a traffic shock wave?

    This was a Halliday Resnick Problem on the linear motion. I could have see the solution but I was not satisfied because I have not get the idea behind the solution. Could you please help me to explain what is exactly the problem is? Or, how to model the shock wave? So that I can make the...
  5. H

    G-force to pressure relationship inside a shock wave

    I need some help understanding shock waves, particularly the units of measure related to their pressure. Shock waves are frequently quantified as multiples of G, the gravitational constant. I need to understand how the G measurements related to the instantaneous pressure within the wave as...
  6. G

    I What is the speed of a shock wave?

    There is lots of good information online about shock waves but I'm not finding what I want. If dynamite has a detonation rate of 6800 m/s does the shock wave travel at 6800 m/s? Is sound we hear 1 mile away the shock wave or the sound? What speed is an atom bomb shock wave? This large horn...
  7. rudransh verma

    Car traffic producing shock wave

    I don’t get where exactly the lengths start and end in figure.
  8. C

    I How do shockwaves in a 1D linear lattice work?

    I am struggling to understand shocks in a one dimensional lattice with a linear spring connecting the masses. Say I have a one dimensional lattice with a linear spring constant, k and lattice spacing a. If the particles in the lattice has mass, m then my speed of sound c is a*sqrt(k/m). That is...
  9. K

    A Thermal shock wave question from my hydrodynamics simulation

    This is a fluid dynamic simulation. The top area has 100 degrees Celsius. The bottom area has 0 degrees Celsius. And both are filled with an ideal gas which is 1-atmosphere pressure. Two areas are connected through the left small line. Another part is blocked. So heat transfer can only happen...
  10. E

    Required time and distance calculation of a shock wave

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  11. B

    Focused Acoustic Shock Wave Device for Generating High Pressures

    I am trying to come up with a design for a device that can generate very high and very brief waves of pressure directed at a 1 mm diameter target (shown as "E" in "Diagram.PNG") housed in a steel support structure "D". The idea is to accelerate hammer "A" towards anvil "B" in a vacuum tube. The...
  12. J

    I How do waves following a shockwave catch up to the shock wave?

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  13. B

    Shock wave through a liquid metal filled steel tube

    Would an A36 steel tube filled with liquid mercury be able to transmit a shock wave longitudinally through the liquid mercury with a peak pressure higher than the yield strength of the steel tube? My thinking is that since the shock wave is traveling normal to the tube wall, it should not be...
  14. T

    Shock Wave Front: How Does Source Movement Create Waves?

    So when the source is not vibrating, it is not setting waves due to vibration? But it is moving so it is still causing disturbance in the medium ... And I happened to read that if the source is moving faster than the speed of sound, a shock wave is set up. How ?
  15. F

    Shock wave system of equations

    Homework Statement This is Rankine-Hugoniot conditions at a hydrodynamic shock front. Where P2=0 v2=0. The problem is attached. I need to solve a system of equations. I thought it would be relatively straight forward solving for the three unknowns but I'm struggling. I know it's possible to...
  16. evinda

    MHB Solving the Shock Wave Problem for $u_t + uu_x = 0$

    Hello! (Wave) I want to solve the equation $u_t+uu_x=0$ with the initial condition $u(x,0)=1$ for $x \leq 0$, $1-x$ for $0 \leq x \leq 1$ and $0$ for $x \geq 1$. I want to solve it for all $t \geq 0$, allowing for a shock wave. I also want to find exactly where the shock is and show that it...
  17. A

    Stagnation pressure across a normal shock wave

    A body is reentering the Earth's atmosphere at a Mach number of 20. In front of the body is a shock wave. Opposite the nose of the body, the shock can be seen to be normal to the flow direction. Determine the stagnation pressure and temperature to which the nose is subjected. Assume that the air...
  18. T

    Pressure wave vs. Shock wave in solid body

    Hi everyone, I'm having some difficulty comprehending "normal" transmission of stress/strain through a solid body and "shock" transmission of stress/strain. Imagine I have two bodies, one rigid - the other elastic. If the rigid body is fixed in space, and the elastic body is flying at the...
  19. Iron_Man_123

    Traffic shock wave physics -- please explain

    Homework Statement Homework Equations N/A The Attempt at a Solution I can't even understand the question and what is happening in the situation :(
  20. A

    What is a very weak shock wave? (Gas Dynamics)

    I stumbled upon this concept when studying gas dynamics. What I get from my readings it must occur when Mach number is really close to 1. But I didn't understand how the property relations across a shock wave is affected by it.
  21. H

    Problem regarding a Normal Shock Wave and Blunt Nosed Object

    Am not sure if I've posted in the right section but I couldn't find anything relevant to Waves in Supersonic Flow, so apologise in advance! Post is a little long but I will appreciate any help! Academically am not very gifted and also have a mathematics disability so I tend to question even the...
  22. nicholas0211510

    Shock Wave Questions: Calculating Speed & Intensity

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  23. T

    Wave Potential of Slamming a Household door?

    I have a physics question about slamming doors and explosions. I've heard before that an explosion releases shock waves through the air that can severely damage a person's vital organs. Recently, I had a door slammed in my face (not literally, it did not hit my face). This wasn't a normal "door...
  24. B

    Shock Waves Traveling to the Ground from a Jet

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  25. A

    Totally Hypothetical, probably incorrect, Shock Wave Generation Mechanism

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  26. S

    Understanding Compressible Shock Waves: Exploring Theta, Beta, and Mach Curves

    Hi all, I have some prob to undestand the shock wave in compressible flow, more precisely the "theta, beta, Mach curve) - Why when "theta" exceeds theta (max) there is no oblique shock? (how we can explain this physicaly)? - What is the difference betwwen weak shock and strong shock? - why in...
  27. Eagle9

    What the destructive force of the shock wave depends on?

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  28. D

    Energy and radius of a shock wave

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  29. T

    What exact speed point does shock wave start to appear

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  30. M

    Velocity of a particle exposed to a shock wave?

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  31. N

    [Fluid dynamics] Normal shock wave problem

    Homework Statement Air, supplied by a reservoir at 450 kPa, flows through a converging-diverging nozzle whose throat area is 12 cm^2. A normal shock stands where A1 = 20 cm^2. (a) Compute the pressure, p2, just downstream of this shock. Still farther downstream, where A3 = 30 cm^2, estimate (b)...
  32. E

    Gas Dynamics (Compressible Flow) Normal Shock Wave

    Homework Statement Suppose that a blast wave, which might have been initiated by an atomic bomb explosion, is traveling through air at standard atmospheric conditions with a speed of 60,000 m/s find change in ( pressure , temperature , stagnation pressure , velocity ) produced by the wave...
  33. T

    Solving for shock wave angle using Mach and deflection angle

    I am trying to show how the shock wave angle varies as I hold the deflection angle constant and increase the Mach number. I am trying to solve for Beta (shock wave angle) using the theta-beta-mach relation: tan(θ)= 2cot(β) * (M2sin2(β)-1) / (M2(1.4+cos(2β))+2) This seems like it should be...
  34. S

    Exploring Shock Waves: Supersonic Flow Experiments

    Homework Statement Anyone know of any experiments I can do show demonstrate a shock wave or supersonics flow ? The Attempt at a Solution Closest thing I can think of is whipping a whip, because the end moves supersonic
  35. A

    Equation of temperature increase by shock wave

    【HELP】Equation of temperature increase by shock wave Hi there! What is the equation of the temperature increase when the ideal gas swept by a planar shock wave (Mach number, M)? Thank you!
  36. J

    Difference between blast & shock wave

    Hi guys and gals, with respect to SNRs (or anything for that matter) What is the difference between a shock wave and a blast wave? Is it just that a blast wave is a sharp peak in the change in variables, where as a shock wave has a region behind it in which the variables gradually...
  37. S

    Difference between shock wave and shock ?

    So I know what a shock wave is but what's a shock ? is it just the front of the shock wave ?
  38. U

    How fast do you have to heat air to create a shock wave?

    Suppose you have a 1cm diameter heat source suspended 2m above the ground. How many watts of heat energy does it need to expend to create a shock wave?
  39. A

    If a bullet was singing a song, what would the shock wave sound like?

    I'm trying to wrap my head around shock waves produced by bullets and their properties. In particular I'm interested in what affects the duration of the shock wave in time. Say someone shoots at me, the bullet passes near me, and I hear the shock wave produced by the bullet. If you look...
  40. R

    Is the Red Dashed Shock Present at Freestream M=2?

    At freestream M=2 will the red dashed shock exist? I know there is a shock wave on the bottom.
  41. B

    Spherical shock wave propagation in liquids

    Dear topic mates! I'm an electric engineer and physicist student from Hungary. I looking for description of the spherical shock wave propagation in liquids. I need a formula which give the relationship between the propagation velocity and time. Additionally, I wonder the pressure at the...
  42. G

    Traffic Shock Wave - Speed & Direction of Wave

    An abrupt slowdown in concentrated traffic can be travel as a pulse, termed a shock wave, along the line of cars, either downstream (in the traffic direction) or upstream, or it can be stationary. Figure below shows a uniform spaced line of car moving at speed v = 25.0 m/s toward a uniformly...
  43. R

    Supersonic Jet: Mach 3 at Altitude 20,000m - Shock Wave & Boom Times

    Homework Statement A supersonic jet traveling at Mach 3.00 at an altitude of 20,000 meters is directly over a person at a time t=0 as show in figure (see below). (a) At what time will the person encounter the the shock wave? (b) Where will the plane be when the "boom" is finally heard? (Assume...
  44. B

    Shooting method and a shock wave (discontinuity at the inner boundary condition)

    I've done searching on the topic, and I really don't know where else to turn, so here it goes. I hope somebody can point me in the right direction. I've been working on using a shooting method to solve the steady-state spherically symmetric fluid equations for an accreting plasma. Basically, it...
  45. N

    How to Calculate Shock Wave Cone Angle and Plane Speed in a Sonic Boom Situation

    Homework Statement You look directly overhead and see a plane exactly 1.4·km above the ground, flying faster than the speed of sound. By the time you hear the sonic boom, the plane has traveled a horizontal distance of 2.4·km. (a) Find the angle of the shock wave cone. (b) Find the...
  46. Z

    How does the V shape of a shock wave depend on the speed of the wave source?

    Hello, the question I have to answer is above in the Title...I thought that the V shape of the shock wave gets wider the faster you are going. No? Thanks Zach
  47. T

    When a star explodes, does the shock wave

    When a star explodes, does the shock wave move faster than the local speed of light? If it does, what effects would this have? A little explaining is in order... While the actual speed of light does not change (c in a vacuum) the overall progression of light is greatly slowed down due to...
  48. H

    Why isn't there shock wave in this case

    Hi everybody ! I have used FLUENT to do the following simulation ( it's 1.5 cm, not 1,5) http://upload.tinhco.net/thoai/debai.jpg I set 500 for "Number of Iterations". After running Fluent, I saw CL and Cd have convergenced, then I turn off the interation process. And here are my...
  49. L

    What Is the Shock Wave Cone Half-Angle at Mach 2.30?

    What is the shock wave cone half-angle for a supersonic airplane flying at Mach 2.30? Would you use Mach=1/sin(theta) and then divide by 2 to get the half angle? So 2.30=1/sin(theta)=12.9 degrees
  50. magi

    MasterIs the existence of gravity shock waves in the universe possible?

    Gravity shock wave... Hi. What if there is gravity shock waves in the univers. I asked a professor once and he said that they can't exist becouse it need infinit energy to create a gravity shock wave. But what if they were created in the big bang so we have gravity shock waves now in the...
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