Looking for a reference for upper limit of fire travel or fire flow
Average speed is around 20 km per hour
ref
https://sciencing.com/fast-can-forest-fires-spread-23730.html
This is good reading
Bushfires 1: Understanding bushfires
https://www.science.org.au/curious/bushfires
Bushfires are a natural, essential and complex part of the Australian environment and have been for thousands of years.
Fire has three essential requirements: fuel, heat and oxygen. Deprive it of any one of these and it will go out.
Different types of bushfire fuel (vegetation) burn differently: finer fuels like grasses burn more quickly, while more substantial, woodier fuels burn with greater intensity.
A bushfire will occur when there is sufficient dry fuel to burn, weather conditions are hot, dry and windy, and there is a source of ignition, such as lightning.
People living in fire-prone areas must prepare a bushfire survival plan and be ready to carry it out.
Much of the Australian bush has been shaped by bushfires, with some plants requiring intermittent burning to complete their life cycles.
more….
During a fire, embers can travel up to 40 kilometres, starting spot fires well ahead of the fire-front – often without warning.
Flame temperatures can reach up to 11000C and radiant heat fluxes high enough to vaporise vegetation, only adding speed to the scorching hot flames.
A fire will burn faster uphill. This is because the flames can easily reach more unburnt fuel in front of the fire. Radiant heat pre-heats the fuel in front of the fire, making the fuel even more flammable.
For every 10˚ slope, the fire will double its speed. For example, if a fire is traveling at 5 km per hour along flat ground and it hits a 10˚ slope it will double in speed to 10 km per hour up the hill.
By increasing in speed the fire also increases in intensity, becoming even hotter.
still not much on upper travel limits
still seeing low numbers
here is something
https://www.science.org.au/curious/bushfires
The heat of the fire can cause thunderstorms or pyrocumulus clouds. These can produce lightning strikes, which can start new fires. With the right combination of atmospheric conditions, fire tornadoes can be created. These can have wind speeds of greater than 250 km/h and are extremely destructive.
but does the fire travel at that speed or just the tornadoe?
See if this link works. It’s CSIRO stuff, but it’s not recent.
https://sci-hub.tw/https://doi.org/10.1071/WF9930193
buffy said:
See if this link works. It’s CSIRO stuff, but it’s not recent.https://sci-hub.tw/https://doi.org/10.1071/WF9930193
geeez sibeen will be all over that!
buffy said:
See if this link works. It’s CSIRO stuff, but it’s not recent.https://sci-hub.tw/https://doi.org/10.1071/WF9930193
Thanks.
This is an interesting video
The CSIRO have the Pyrotron.
https://www.csiro.au/en/Do-business/Services/Enviro/Pyrotron
There are links to published papers.
ChrispenEvan said:
buffy said:
See if this link works. It’s CSIRO stuff, but it’s not recent.https://sci-hub.tw/https://doi.org/10.1071/WF9930193
geeez sibeen will be all over that!
The link works? I had to go to it in a roundabout way.
Starting point for CSIRO
https://www.csiro.au/en/Research/Environment/Extreme-Events/Bushfire/Bushfire-research
buffy said:
ChrispenEvan said:
buffy said:
See if this link works. It’s CSIRO stuff, but it’s not recent.https://sci-hub.tw/https://doi.org/10.1071/WF9930193
geeez sibeen will be all over that!
The link works? I had to go to it in a roundabout way.
yep, goes to a page where you download a PDF BEER1993
And the fire behaviour section of the Bushfire CRC. Quite a bit of reading there, I think.
http://www.bushfirecrc.com/category/bushfiretopic/fire-behaviour
ChrispenEvan said:
buffy said:
ChrispenEvan said:geeez sibeen will be all over that!
The link works? I had to go to it in a roundabout way.
yep, goes to a page where you download a PDF BEER1993
Thanks. I’m sometimes not sure about something I followed through the wilds of SciHub.
speed of sound
Tau.Neutrino said:
Looking for a reference for upper limit of fire travel or fire flow
Average speed is around 20 km per hour
ref
https://sciencing.com/fast-can-forest-fires-spread-23730.html
> speed of sound.
LOL
I’ve struck three cases where bushfires move very fast.
An EF1 tornado has wind speeds of 138–177 kph. https://en.wikipedia.org/wiki/Enhanced_Fujita_scale
The speed up valleys. “For every 10˚ slope, the fire will double its speed” from https://www.cfa.vic.gov.au/plan-prepare/how-fire-behaves So a fire at 6 km/hr along the flat could become about 192 km/hr up a 50 degree slope, perhaps.
But these are relatively local. Let’s see if I can look at bulk speed over long periods of time, though.
https://www.firescience.gov/projects/09-S-03-1/project/09-S-03-1_final_report.pdf
“Wind-driven crown fires have been documented to spread at up to 100 m/min for several hours and in excess of 200 m/min for up to an hour.” 200 m/min is only 12 km/hr.
The Black Saturday fires (Kinglake area in 2009) were fanned by winds 125 km/hr. From https://en.wikipedia.org/wiki/Black_Saturday_bushfires