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Questions tagged [shock-waves]

A shock wave is the final stage of a nonlinearly steepening wave that has reached a balance between steepening and energy dissipation resulting in a discontinuity.

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Can supersonic flow be achieved without converging diverging nozzle?

Can supersonic flow be achieved without the presence of a converging diverging nozzle if sufficient pressure difference is available? https://www.tomshardware.com/desktops/pc-building/an-ordinary-...
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Deflecting a lunar mass with consecutive nuclear explosions [closed]

I'm looking for help in determining the amount of deflection an object with a mass of roughly $7\times10^{22} \,\text{kg}$ (a lunar mass) needs from colliding with a planet. Let's stipulate that the ...
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Burgers' equations and shock waves

Given Burgers' equation, $m_{\tau} + mm_x = 0,$ one expects to have discontinuities and thus shock waves in the case the initial conditions are smooth. For example, one may take $m_0(x) = \sin(x), x\...
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Burger equation and shock waves

Given the burger equation, $$m_{\tau} + mm_x = 0,$$ one expects to have discontinuities and thus shock waves in the case the initial conditions are smooth. For example, one may take $$m_0(x) = \sin(x),...
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Does a rubber mat reduce the impact to the floor below?

My lack of physics knowledge is preventing me from solving an everyday life problem. Please bear with me! Say I have a second-floor apartment and I want to do deadlifts. I am afraid of the floor ...
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What is the entity that resides at a point with a radial coordinate $r$?

In his groundbreaking paper The formation of a blast wave by a very intense explosion I. Theoretical discussion, G.I.Taylor presented a number of equations, including the ones depicted below: In ...
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How did G. I. Taylor derive the PDE's in his landmark 1941 paper?

To gain a deeper understanding of the derivation of G. I. Taylor's foundational equation $R= S(γ)t^\frac{2} {5} E^\frac{1}{5} ρ_0^\frac{-1}{5} $, I'd be grateful if you could point me towards the ...
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Why do shockwaves refract when they travel into the ground?

If a shockwave from something like an explosion travels into the ground, why will it refract? The speed of sound is far different in the ground, but what would make it refract? I can’t seem to find ...
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How are shockwaves able to refract?

How are shockwaves able to refract? As said here, When two shock waves collide, they interact with each other and produce complex patterns of compression, rarefaction, and reflection. The resulting ...
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How do shockwaves interact?

As seen here, there are two T-38's going supersonic. What happens when those shockwaves interact? They seem to dissipate in some places on this photo when they interact. Any source online says that ...
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Does every shockwave have an expansion wave behind it?

Do all shockwaves have an expansion fan or expansion wave behind them? Does the air always expand behind a shockwave? I assume that the strength of the expansion wave depends on the strength of the ...
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How is the second shock in a lambda shock able to form?

For an oblique shock to form, there has to be an angle in which the flow turns into itself. Usually, that angle is caused by flow separation, in which the separation is caused by a normal shock first, ...
Wyatt's user avatar
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Sonic boom on atomic particles

we know that something travelling faster than the speed of sound creates a continuous sonic boom because the air cant get of its way fast enough but if we consider smaller particles which can travel ...
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Where are the results of the smoke mortar measurements of the shock wave in nuclear tests?

Smoke mortars were used in nuclear tests to measure the passage of the shock wave. The passage of the shock wave could be detected by the sunlight reflected from the smoke trails being refracted ...
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Intuition behind retarded/causal Green's function for the 1+1D wave equation

I see that the retarded/causal Green's function for the 1+1D wave equation is $$ G(x, t \,|\, x_{0}=0, t_{0}=0) = \frac{1}{2c} H(t - |x/c|), $$ (where $H$ is the Heaviside step function) which ...
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Photons and gravitational wave

Both photons and gravitational disturbances travel at $c$. Given that a photon does cause a tiny stress in spacetime due to its energy, and the propagation of this stress is at the same velocity as ...
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Does anyone know of published data on Mach interactions with various asymmetrical toroids?

I was looking for any lab conducted tests, or computer models of Mach reflections off of different toroids. How would shock waves propagate through asymmetrical 180° ring toroids, what kind of ...
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What happens when the shockwave is opposing the flow direction

There is a supersonic flow over a flat plate (assume inviscid--no boundary layer). Suddenly, there is a point blast occurring on the flat plate, generating a semi-spherical shock wave. For the ...
Faito Dayo's user avatar
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Theta-Beta-Mach relation for small deflections

I'm currently studying shockwaves, particularly their effects on drag. I've stumbled upon an odd formula in "Elements of Gasdynamics" (Liepman and Roshko, pages 52-53), in there I saw an ...
Mike November's user avatar
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2 answers
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Why is there sound aboard Concorde after it goes supersonic?

I recently saw a video from a passenger of Concorde after it goes supersonic. Inside the aircraft, there is still a loud roar similar to what we hear in aircraft today. However, since the aircraft is ...
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Shock wave’s energy transfer between different mediums

This topic fascinates me, but my knowledge about shock waves — the physics behind them and the way they conduct energy — is very limited. I wanted to ask then for some elucidations, about what happens ...
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Taylor flat plate theory with local cavitation

Background I'm studying the so-called Taylor flat plate theory. The problem considers an infinite plate which separates a region of water from a region of air. There is an incident shockwave from the ...
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Hyper-saturated blue colour in underwater explosions?

I've been looking at underwater explosions from various US navy shock trials: e.g. https://www.youtube.com/watch?v=yV0eyP4nO20 and https://www.youtube.com/watch?v=PS2whGDzmzg If you go frame by frame ...
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Volume Conservation in Shock Plastic Waves [closed]

SOLIDS: Plastic deformation is known to have constant volume. During shock, does the plastic wave not compress the volume? Should the only compression come from the elastic wave? Edit-1: screenshot
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In nuclear weapons, why does levitating a pit improve compression?

Levitated pits were introduced after after solid pits. In this design the tamper is separated from the fissile with an airgap. From the Nuclear Weapon Archive: The original Fat Man pit design used a ...
Jane Bass's user avatar
5 votes
2 answers
359 views

Are there shock waves outside of fluid dynamics?

In general, conservation laws can result in shock waves, i.e. locations where a variable changes quickly and a discontinuity arises. One of the most common examples that is always mentioned is the ...
Thomas Wagenaar's user avatar
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Derivation of the Mach number of the reflected shock in shock tube

I am a new learner in compressible aerodynamics. When studying the shock tube, I struggle to derive the relationship between $M_{s}$ and $M_{R}$ after the shock is reflected from the end wall. How ...
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A shock propagates in to stationary air at $M$. Find the speed of the air (fixed frame reference) after the shock has passed

The speed of sound prior to completion of the shock is $M_1 * a$, where a is the speed of sound at that point. The solution is then that the speed of the air after the shock has propagated is $(M_1 * ...
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Laser induced explosion (detonation)

I have a question involving quite the wacky (and silly) hypothetical. It's a part of an ongoing argument I'd like to settle. Of course, I have no background in physics which is why I came here, so I ...
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What is a relatively simple/heuristic formula to find the yield of an explosive given the peak overpressure and the mass of the charge? [closed]

Suppose one can experimentally determine the two parameters mentioned in the question, are they enough for a good approximation of the yield of the explosive? I am thinking there are some ways to do ...
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1 answer
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Propagating of shock waves in an ideal gas

I am studying gas dynamics and I want to numerically calculate the propagation of a shock wave in an ideal gas. The problem statement is something like this: The ideal gas is located in the region $-\...
Daniil Udalov's user avatar
12 votes
1 answer
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Shock when a supernova explodes

I have been reading that when supernovae explode, they produce (Shockwaves) which act as cosmic accelerators. I do not understand, what is meant with "shock" (partially because I do not ...
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Dynamic equations for a gas discharge lamp

This question asks why a gas discharge lamp is blinking and making a noise when it is turned on. I think that the lamp (with potential on) is a bi-stable system where the current-carrying "bright&...
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How does transition from supersonic to subsonic flow occur?

I was working with orifices that were restricting flow and had to do a few calculation to verify some measurments (and to see if stuff was within tolerances). So I stumbled upon the calculations our ...
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3 answers
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How much do tunnels extend blast waves from explosives?

As was discussed in the comments, I've crossposted this question to here, and am cross-linking them: https://worldbuilding.stackexchange.com/questions/234669/how-much-do-tunnels-extend-blast-waves-...
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With blast injuries, how much of the damage is from rapid decompression? [closed]

If a person or creature suffers a high explosive or low explosive blast, how much of their injuries will be due to the sudden decompression immediately after the shockwave? Sudden decompression can ...
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1 answer
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Rarefaction Shocks, Bethe-Zel'dovich-Thompson (BZT) Fluids

In his 1988 book Compressible Fluid Dynamics, Philip Thompson (Ransselaer Polytechnic) defines the fundamental gas dynamics derivative, viz. $$\Gamma = \frac {c^4}{2v^3} \left(\frac{\partial^2v}{\...
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Do chemical reactions occur inside of the Shock wave?

I am currently reading Anderson's book on hypersonic aerodynamics. In the energy Navier-Stokes equations its is very common to ignore Dufour effect, which is (as I understand) non-negligible when huge ...
Mukhamejan Baimoldayev's user avatar
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1 answer
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Can elastic mediums snap at a faster speed than the wave which travels in it?

The speed of wave in an elastic medium is given by Velocity of Longitudinal Wave 1) Velocity of Sound in any Elastic Medium: It is given by $v=\sqrt{\frac{E}{\rho}}=\sqrt{\frac{Elasticity\,of\,the\,...
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2 answers
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Can the dynamic between high speed sound media and slow one preduce shock wave?

Suppose there is two long media that in one of them the speed of sound is high and in one of them is slow. Would the vibration in the one with the higher speed of sound would cause shock wave in the ...
Daniel Haish's user avatar
4 votes
1 answer
230 views

Clapping-like sound from large planar object hitting a surface

I am trying to understand the behavior of air when a large, planar object hits a parallel surface at a high velocity, thus forcing the initially static air outwards, and creating a sound wave. This is ...
Ron Shvartsman's user avatar
2 votes
1 answer
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Utility of Burger's equation in the study of shock waves

Consider the viscous Burger's equation, $$ \frac{\partial u}{\partial t}+u \frac{\partial u}{\partial x}-\nu \frac{\partial^{2} u}{\partial x^{2}}=0, \tag{1} $$ with $\nu>0$ the kinematic viscosity....
Invenietis's user avatar
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Are seismic waves and shock waves same?

Are shock waves (those produced by high speed jets) and seismic waves (produced during earthquake) the same? In many places I have seen seismic waves referred to as shock waves. So are these two same?
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How would high-explosives interact with the shockwaves around a hypersonic weapon?

This is a proxy for a question from a friend. I'm an aerospace engineer so I have some domain-knowledge on compressible flow but less about missile design and even less about explosives. I also ...
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6 answers
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Gravitational waves manifestation of 'physical' spacetime?

When a stone is thrown in water, water waves are created. The stone imparts its kinetic energy to water. Likewise a sound speaker imparts its kinetic energy to air molecules. When an electron falls ...
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Shockwaves in a colllision of two cylinders

On Motion Mountain's first volume (fall, flow and heat) by Christoph Schiller, page 128, the author asks the following puzzle: A surprising effect is used in home tools such as hammer drills. We ...
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7 answers
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Is submersion in a canal a good way to shelter from a nuclear strike?

I live 1.5 miles from the center of a city in a nuclear-armed country, and an adversarial country has just put its nuclear forces on high alert during a time of extraordinary geopolitical tension. I ...
Tom's user avatar
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2 answers
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Theoretical rocket engine based on plasma shock waves particle acceleration

Credits for the article - https://www.quantamagazine.org/cosmic-map-of-ultrahigh-energy-particles-points-to-long-hidden-treasures-20210427 Can this mechanism be used to speed up gas particles to ...
Corneliu Maftuleac's user avatar
1 vote
1 answer
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Sound wave travelling from high impedance to low impedance medium, what will be the reflection & transmission coeffiecient?

Let us assume that a wave propagates in the direction perpendicular to the flat surface of discontinuity. When the characteristic impedance of the medium of medium 0 (where the incident and reflected ...
BenDover Investigation's user avatar
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Curved shocks and vorticity generation

In fluid dynamics, it is known that curved shocks (which are common, e.g., in bowshocks) generate vorticity. I am looking for a quantitative derivation.
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