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arungeth January 16, 2014 12:26

Shock wave
 
Is shock wave stationary one? if yes,why it is called as wave?

FMDenaro January 16, 2014 13:34

Quote:

Originally Posted by arungeth (Post 470375)
Is shock wave stationary one? if yes,why it is called as wave?

not necessarily ... "steady shock wave" is a modelization you can use (a travelling wave at constant velocity is studied as a steady one) but you can have different problems, for example unsteady model provided by the Burgers equation that governs the shock formation or the case of homoentropic flows with compression that tends to form a shock, Riemann problems or other more complex cases...

AshwaniAssam January 18, 2014 12:35

Shock wave is create when the flow is supersonic. These are governed numerically by hyperbolic equations, which uses characteristic waves to know the solution. Now, I am guessing when these waves corresponding to the particular hyperbolic equations, gives a abrupt change in their values it is called "shock" wave. Please confirm it with the origin of the word.
Also, wiki writes "A shock wave is a type of propagating disturbance. Like an ordinary wave, it carries energy and can propagate through a medium (solid, liquid, gas or plasma) or in some cases in the absence of a material medium, through a field such as the electromagnetic field. "
Also, shockwave creates disturbance in the flow-field even if it is a stationery shock. So, it a wave.

FMDenaro January 18, 2014 13:12

unsteady Euler equations are hyperbolics both in subsonic and supersonic regimes ... the classical example of the shock tube can be helpful to understand the meaning of travelling waves

AshwaniAssam January 18, 2014 14:02

Quote:

Originally Posted by AshwaniAssam (Post 470640)
Shock wave is create when the flow is supersonic. These are governed numerically by hyperbolic equations, which uses characteristic waves to know the solution. Now, I am guessing when these waves corresponding to the particular hyperbolic equations, gives a abrupt change in their values it is called "shock" wave. Please confirm it with the origin of the word.
Also, wiki writes "A shock wave is a type of propagating disturbance. Like an ordinary wave, it carries energy and can propagate through a medium (solid, liquid, gas or plasma) or in some cases in the absence of a material medium, through a field such as the electromagnetic field. "
Also, shockwave creates disturbance in the flow-field even if it is a stationery shock. So, it a wave.

Adding to it, the disturbance here is in the sense of Longitudinal wave. i.e. compression and rarefaction, and not transverse waves. Under steady condition, it seems stationery.


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