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shock

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. V

    Shock to the system :-(

    I've been contracting for the last couple of year and been getting home around 3 everyday and having the weekends all to myself. As I'm looking at buying a house I've been to see a mortgage advisor etc and I can get to mortgage I need but I'm 11k short on my deposit. So I called the manager...
  2. turnpin

    Shock horror!!!

    Bought new 45 amp cooker switch so thought pay the extra and buy good old British brand MK only to find now made in Malaysia how long has this been going on?:rolleyes2:regards turnpin
  3. S

    Load vibrating from Boiler on cold tap (intermittent)

    Evening guys. I have an issue with my glowworm cxi30 whereby occationally when i run the cold tap for a few seconds (maybe 5 seconds) the boiler makes a loud vibrating noise for about 4-5 seconds after closing the tap. This is happening from different taps in the house. Again this is...
  4. M

    Just had a nasty shock

    I just logged into my online banking and clocked my balance -£44,660.00 I nearly crapped myself until I realised that the bank have added my mortgage statement onto the online stuff as well and it appears second down in the list where my current account normally appears. I thought I'd been...
  5. Simon F

    opening cold tap has effect on boiler

    I think I read a similar thread on this but can't find it. glowworm combi, turn on a cold tap and most times the fan ( I think fan just from listening ) runs for a minute or so. is this just a glitch that sometimes happens? is the solution simply to fit a check valve on the cold feed, if so...
  6. P

    water hammer prevention

    hi there just replaced old bath taps and basin taps for cermaic discs ones, but as these ones are 1/4 turn on and off you can turn them off quickly, if you turn the cold off quickly then it creates a bad knocking noise, have checked all pipework and nothing seems loose ( everything lagged and...
  7. D

    shock absorbers

    has any body used these small expansion vessels to combat water hammer.
  8. SimonG

    Bit Of A Shock!!!!

    Went to look at a dodgy thermostatic mixer shower on saturday morning, Triton Aspirante, quite dated. Cartridge has gone. Just checked online to see how much £299!!!:shocked: Apparently can't change cartridge, have to change full valve.
  9. SimonG

    Shock of the Day!

    Needed a second immersion for a center store unvented cylinder. Turns out they use Heatrae sadia £74 + vat:eek: If I'd known I would have shopped online.
  10. P

    15 ltr under sink unvented

    came accross one today and expansion vessel was 0.5 ltr i would say at a minimum it would need to be a 4ltr i recommended a 6 ltr though
  11. B

    nasty shock

    had a nasty electric shock to day,was faulting a potterton puma as some of you know when faulting you do it under live conditions,anyway what happened was this no power on lights to boiler so after checking fuse and supply cable i had todrop down the main pcb houseing[done this with power...
  12. A

    Redundancy Shock

    After 1 year and 5 months with this company, I was totally shocked to find that they had no work for me this week and I don't expect to have any soon considerig the bulk of their work is in the New Housing market. So, as I never foresaw this as they have looked after me very well since I...
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