Calc group discussion: Calculations of explosions using nuclear weapon laws

[DontTalk]

So this thread is mostly of interest to the calc group.

So what I want to do is to officially decide how the calculation of explosions based on their radius should be handeled, so that we are all on the same page regarding that.


My method to this point is what currently stands on our calculations page in combination with what was discussed here.

In other words if it's an actual nuclear explosion just use the calculator for what fits, if it's not an actual nuclear explosion use near-total fatalities and take the result times 0.4 (low end) or 0.5 (high end).


Are there special cases or completly other methods that should be considered? If yes: That is what this thread is for.

 

[Gwynbleiddd]

I'm fine with these, just one more thing.If the explosion is clearly a fireball then we should use the fireball option in the calculator while in other cases where there is a lot of smoke like here then we should use near total fatalities.

 

[DontTalk]

If we use fireball 0.3-0.5 should be used, but I am not sure if that is a good idea. To quote myself from a recent conversation with Alakabamm:

"The size of a fireball is more complicated. For example small amounts of tnt more or less produce none. In case of a nuke thermal radiation and so on are the cause for a fireball, while another explosive might cause it through burnable material that is spread by the shockwave and ignited. If you throw fiction energy in it it's even more uncertain.

In that sense the near total fatalities value might be safer, because it is a low end for once and because it is likely legitimate to assume that a normal human would have died in the explosion diameter, which they usually do through impact and not through being burned. Impact can be better assumed to hold true even if fiction energy is involved.

But all in all I guess it's just the safer bet. "

 

[Gwynbleiddd]

0.4-0.5 should be used at all times except for cases like nuclear bombs, anti matter stuff etc.

What Alakabamm said is true, that's why it's better to use near total fatalities.But in cases like this fireball is the best option

 

[DontTalk]

the above was a quote from myself not from alakabamm.

Well, Thermal radtation from nuclear weapons is actually 0.3-0.5, so if you talk about the fireball the energy to consider is the energy of heat that causes the fireball, not that of the blast that contributes to the pressure wave.


And cases like you have shown are the ones why I have the opinion fireball should not be used.

We have here something that is first a giant energy/chakra sphere and only later on turns into a fire explosion. In other words not the whole expansion of the fire is done from the center, and the energy causing the fireball is transmitted most of the radius though chakra and the fire is directly caused by the chakra instead through the heat radiating outwards.

In other words the spread behavior of the fire here is very different when compared to the fireball spread of a nuclear weapon, which at the center for short instances have temperatures far above what usual fire techniques in fiction display.

 

[Alakabamm]

Well, to an extent, the chakra techniques that we see (from Bijuu at least) end up with blasts far larger than the form they start in, so there must be some form of decompression occurring. Whether this is close enough to the spread of a nuclear weapon to work with the equations given, however, seems beyond me. Maybe we need to read the source of the calculator, as I believe it is still up on some sites.

BTW, I decoded the equations from the nuclear page. I will just copy and paste them here if you are interested.

var Y0 = form.yield.value; var Y1 = Y0 * 400; var Y2 = Y0 * 1000; var thermal = pow(Y1,0.41); var blast = pow(Y1,0.33); var radiation = pow(Y1,0.19); var blastkill = pow(Y2,0.33)*0.28; var duration = pow(Y0,0.45)*4.5; var rad1 = round((pow(Y2,0.4)*90/3.3)/10)/100; var rad2 = round((pow(Y2,0.4)*110/3.3)/10)/100; var rad3 = round((pow(Y2,0.4)*145/3.3)/10)/100

This can be decoded into the following equations:

Thermal radiation radius (3rd degree burns) Yield: Y=((x)^2.439)/400

Air blast radius (widespread destruction) Yield: Y=((x)^3)/400

Air blast radius (near-total fatalities) Yield: Y=((x/0.28)^3)/1000

Ionizing radiation radius (500 rem) Yield: Y=((x)^5.26)/400

Fireball duration: D=(x/4.5)^2.22

Fireball radius (minimum) Yield: Y=((x/(27.3))^2.5)/1000

Fireball radius (airburst) Yield: Y=((x/33.33)^2.5)/1000

Fireball radius (ground-contact airburst) Yield: Y=((x/43.93)^2.5)/1000

Where Y is the yield in megatons, x is the radius used and D is the duration of the fireball.

Where duration is in seconds, the first four radii are in km and the last three radii in meters.

 

[Lina_Shields]

The equations posted seem to be handy in cases where the explosion is considered to be an air blast, or a fireball.

Drawing explosions similar to what is shown Kkapoios' picture probably would be a pain for the artists and animators, so they just draw a dome-shaped fireball to indicate that an explosion has occurred in that area.

As such, we only see stuff being destroyed when the fireball of the explosion directly reaches stuff, as the fireball is the animator's way of displaying the actual explosion itself, including shockwaves and all [This is because we rarely see actual shockwaves produced by an explosion causing damage in fictional media]

Just use near-total fatalities and multiply the result by 0.5 for general explosions and stuff, keeping thing simple.

 

[Antvasima]

I just wanted to check how things are going with this project?

 

[Lina_Shields]

Well looks like Alakabamm's all set up with the equations. I was wondering if we can use these, or store them somewhere here on site.

 

[Antvasima]

Well, you can obviously incorporate the equations into the page itself, and when it is finished, we can add a link to the front page help section, and the navigation bar.

 

[Lina_Shields]

Just wanted to ask, what is the Ionizing radiation radius? Does anyone know the definition for it?

Anyways, I will add the above equations to the calculations page if there is time.

 

[Antvasima]

Well, it should preferably be added to the specific new explosion calculations page.