Not sure if this is the proper place to put this, but...

I need help with the physics of a mid-air explosion.  I have a ship travelling
in an atmosphere, at about 4000 units per clock.  It is supposed to explode in
mid-air, but I am wondering how the resulting debris would travel.  Would it
travel both to the ground and to an eventual stop, or what.

Any knowledge would be most appreciated.

Thanks in advance,
  --Nimish

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Nimish Ajmani wrote:
> Not sure if this is the proper place to put this, but...
> 
> I need help with the physics of a mid-air explosion.  I have a ship travelling
> in an atmosphere, at about 4000 units per clock.  It is supposed to explode in
> mid-air, but I am wondering how the resulting debris would travel.  Would it
> travel both to the ground and to an eventual stop, or what.
> 
> Any knowledge would be most appreciated.

The solid fragments will fly off in all directions, with the total 
momentum equal to the total momentum of the ship before the explosion.

Acceleration will be be comprised of an amount from gravity (constant 
acceleration, straight down), plus a component of drag (directly 
opposite current motion, directly proportional to velocity, directly 
proportional to cross-sectional area, inversely proportional to mass). 
Remember that velocities and accelerations are all vector values. 
Choose the right coefficient of drag and you will have a convincing path 
of motion for each particle.

The fireball is gaseous, and while it may have a large mass, it will 
also have a very large wind resistance, and less gravity, so its 
trajectory will depart from the solid fragments very quickly.

You will probably need to do some math to step through each frame 
leading up to the frame that you're rendering.

Regards,
John

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"Nimish Ajmani" <nomail@nomail> wrote in message 
news:web.47d97bdddd275636704837900@news.povray.org...
> Not sure if this is the proper place to put this, but...
>
> I need help with the physics of a mid-air explosion.  I have a ship 
> travelling
> in an atmosphere, at about 4000 units per clock.  It is supposed to 
> explode in
> mid-air, but I am wondering how the resulting debris would travel.  Would 
> it
> travel both to the ground and to an eventual stop, or what.

     If the explosion occurs in 'mid-air' as we know it on Earth, then the 
debris will travel to the ground in solid form, but will buckle on impact 
with Earth and cause a large dent in the Earth's surface and kill most.

       ~Steve~


>
> Any knowledge would be most appreciated.
>
> Thanks in advance,
>  --Nimish
>
>

Post a reply to this message

>> Not sure if this is the proper place to put this, but...
>>
>> I need help with the physics of a mid-air explosion.  I have a ship 
>> travelling
>> in an atmosphere, at about 4000 units per clock.  It is supposed to 
>> explode in
>> mid-air, but I am wondering how the resulting debris would travel.  Would 
>> it
>> travel both to the ground and to an eventual stop, or what.
>>
>> Any knowledge would be most appreciated.
>
> The solid fragments will fly off in all directions, with the total 
> momentum equal to the total momentum of the ship before the explosion.
>
> Acceleration will be be comprised of an amount from gravity (constant 
> acceleration, straight down), plus a component of drag (directly opposite 
> current motion, directly proportional to velocity, directly proportional 
> to cross-sectional area, inversely proportional to mass). Remember that 
> velocities and accelerations are all vector values. Choose the right 
> coefficient of drag and you will have a convincing path of motion for each 
> particle.
>
> The fireball is gaseous, and while it may have a large mass, it will also 
> have a very large wind resistance, and less gravity, so its trajectory 
> will depart from the solid fragments very quickly.
>
> You will probably need to do some math to step through each frame leading 
> up to the frame that you're rendering.

There is also blast shadow, objects behind other objects will pick
up less of the momentum from the blast, and be thrown in slightly
different directions because of deflection of the gaseous wave.

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Thanks for all the help, especially to John.

I think I got the effect programmed right, now I just have to wait for a final
result.

I'll post that result probably in the animations section when it is finished.

Post a reply to this message

"Nimish Ajmani" <nomail@nomail> wrote:
> Thanks for all the help, especially to John.
>
> I think I got the effect programmed right, now I just have to wait for a final
> result.
>
> I'll post that result probably in the animations section when it is finished.

For a first approximation I'd add a velocity in a random direction to each
fragment's forward velocity at the point of the explosion, and then let gravity
control them from then on. As others mentioned, any fireball or smoke/fine
particle cloud will likely stay virtually stationary at the point of the
explosion until it dissipates. With some tweaking this would probably look good
enough for most purposes. A simple wind resistance factor (a decelerating force
proportional to existing speed squared) could also be calculated for each
fragment for added realism.

I hope it looks good, this is something I keep meaning to try!

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I posted a preliminary test over in the animations section.  If you all would
take a look and comment, I would be most grateful.

Thanks again for all your help, and Thanks in advance for more help.

 -Nimish

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