Humor Random Comments Thread

[steph]

Yep, it's been a few wild days for severe weather in Central Europe. Normally, the one forming due to a stationary front would be of the landspout variety, but yes...while I wouldn't go as far as saying they form from the ground up, it's almost always stuff in the lower-most inflow layers in surface-based storms that kicks up the feedback loops leading to tornadic formation. I've been a storm spotter for over 10 years now, seen a few funnels, but I still find it hard to wrap my head around the whole thing.

Even with supercells, having a deep rotating updraft and the RFD kicking in surely helps, but even so, not all produce even if all the conditions are met. Packs of more buoyant air, as well as local air currents producing low level shear due to the topography might form the initial vortex, which then gets picked up and stretched, or integrated, in the bigger circulation.

 

[Urwumpe]

Yep, it's been a few wild days for severe weather in Central Europe. Normally, the one forming due to a stationary front would be of the landspout variety, but yes...while I wouldn't go as far as saying they form from the ground up, it's almost always stuff in the lower-most inflow layers in surface-based storms that kicks up the feedback loops leading to tornadic formation. I've been a storm spotter for over 10 years now, seen a few funnels, but I still find it hard to wrap my head around the whole thing.

Even with supercells, having a deep rotating updraft and the RFD kicking in surely helps, but even so, not all produce even if all the conditions are met. Packs of more buoyant air, as well as local air currents producing low level shear due to the topography might form the initial vortex, which then gets picked up and stretched, or integrated, in the bigger circulation.

I think this recent research is very impressive, especially since the problems of creating a tornado in a simulation show that the mechanism must be some kind of chain reaction. Even just compiling the simulation code again with a different version of the same math library is enough to switch a simulation run from EF4 to nothing. At a 30m grid the trigger for a tornado must be something taking place at the least-significant bits of a floating point number.



http://orf.media/


Especially, he speaks my language as a CFD kind of guy - those things like vorticity and procession of vortices makes sense to me and I can point at them in thunderstorms.


In his most recent presentation, he also shows with simulation data, how the tornado is triggered on the ground, showing a sudden increase in vortex stretching (dw/dz) low on the ground.



And it seems like the RFD isn't really as important for the tornado as classic tornado research claims. Things look different if you can make the invisible wind visible.

 

[Matias Saibene]

I can't login in to Orbit Hangar Mods

Hello everyone. I have not used Orbiter (and Orbiter-Forum) for a long time and that's why I'm a bit confused. Is there a problem with Orbit Hangar Mods? I can not log in with my Orbiter Forum account. The site also has an unknown error shown at the top of the page.

My browser is Opera 60.0.3255.151, OS Manjaro GNU/Linux and Windows 7.


I did not want to start a new topic for such a short question, so I posted it here.

Greetings to all.

 

[Marijn]

I can not log in with my Orbiter Forum account.

Your Forum account is not supposed to work for the Orbiter Hanger as well. My account certainly does not work either as I would expect.

 

[Lucy]

Hello everyone. I have not used Orbiter (and Orbiter-Forum) for a long time and that's why I'm a bit confused. Is there a problem with Orbit Hangar Mods? I can not log in with my Orbiter Forum account. The site also has an unknown error shown at the top of the page.

My browser is Opera 60.0.3255.151, OS Manjaro GNU/Linux and Windows 7.


I did not want to start a new topic for such a short question, so I posted it here.

Greetings to all.

No, this should work - but the Hangar is struggling a bit due to some recent essential maintenance works.


I'm looking into it.

Your Forum account is not supposed to work for the Orbiter Hanger as well. My account certainly does not work either as I would expect.

It should do - Vash linked them some years back, so you would log in with a Forum account. You can still log in with older accounts on the Hangar from before the link, but you can't register a new one.

 

[Marijn]

Ok, thanks for making that clear.

 

[Matias Saibene]

I also want to comment that sometimes Orbiter-Forum tells me Error 500 when I try to access my user profile (https://www.orbiter-forum.com/member.php?u=9882).

No, this should work - but the Hangar is struggling a bit due to some recent essential maintenance works.


I'm looking into it.





It should do - Vash linked them some years back, so you would log in with a Forum account. You can still log in with older accounts on the Hangar from before the link, but you can't register a new one.

Thank you for your quick response, I can imagine that maintain a server and two web pages can't be easy, so your work is appreciated keeping everything running for many years. I known O-F since 2012 and it is excellent.

Greetings.

 

[Urwumpe]

A WW2 bomb just exploded in a field near Limburg last night, at 4 AM local time. Created a 10m wide and 4 m deep crater and caused a magnitude 1.7 earthquake

 

[steph]

In a way, it's amazing that the chemicals powering the reaction haven't leaked/degraded in all this time. Makes me think of the few broken arrow incident (and sunken subs) where they haven't recovered the nukes. But then again, the complexity of a nuke should also mean that an impact would screw up the mechanism enough that you get at most a fizzle. It would only be logical that the classical ones are designed to blow pretty much no matter what (hence the late detonations) and a nuke only has a very specific chain of triggers that could make it go off.

Edit: shouldn't the natural decay of the uranium render them incapable of criticality after a few decades?

 

[Linguofreak]

In a way, it's amazing that the chemicals powering the reaction haven't leaked/degraded in all this time. Makes me think of the few broken arrow incident (and sunken subs) where they haven't recovered the nukes. But then again, the complexity of a nuke should also mean that an impact would screw up the mechanism enough that you get at most a fizzle. It would only be logical that the classical ones are designed to blow pretty much no matter what (hence the late detonations) and a nuke only has a very specific chain of triggers that could make it go off.

Edit: shouldn't the natural decay of the uranium render them incapable of criticality after a few decades?

Nope. The primary isotopes used in nukes are U235, which has a half life in the hundreds of millions of years, and Pu239, with a half life around 24,000 years. Neither will be significantly depleted by decay within decades. It takes about 300 years for Pu239 to be depleted by even 1%. For U235, that will take 10 million years.

---------- Post added at 10:28 ---------- Previous post was at 10:19 ----------

A WW2 bomb just exploded in a field near Limburg last night, at 4 AM local time. Created a 10m wide and 4 m deep crater and caused a magnitude 1.7 earthquake

Not a controlled detonation of a known bomb? Farmer Hans is just minding his own business, and then his wheat field gives him an abrupt 4 AM wakeup call?

 

[tl8]

Not a controlled detonation of a known bomb? Farmer Hans is just minding his own business, and then his wheat field gives him an abrupt 4 AM wakeup call?

As long as you ignore the bag of blasting caps in his back pocket. I mean, less faffing around if it goes off 'by itself' at 4 in the morning.

 

[Urwumpe]

Not a controlled detonation of a known bomb? Farmer Hans is just minding his own business, and then his wheat field gives him an abrupt 4 AM wakeup call?

No, it was not even known that there was still a bomb left. It simply exploded.

https://www.fnp.de/lokales/limburg-...xplosion-weithin-hoeren-sagt-zr-12660945.html

About 500 lb heavy, according to experts. It exploded not far away from the main road in that region, I already drove by the location a few times.

And now we also have two Eurofighters that collided midair over Mecklenburg-Vorpommern. One ejected pilot found, the other is still missing. The crash sites are 10 km apart.

https://www.tagesschau.de/inland/eurofighter-absturz-101.html

 

[Notebook]

Are there many of these "spontaneous" explosions?
Any idea what it was aimed at, any airfields or factories nearby?

N.

 

[Urwumpe]

Are there many of these "spontaneous" explosions?
Any idea what it was aimed at, any airfields or factories nearby?

N.

Not sure. West of it is Hadamar, east of it the former main road from Siegen to Mainz. Not known if any of those were target of a bigger raid. 10 km away to the south, Limburg was bombed 12 times in WW2 because of the important train maintenance depot.

Would need some more research to find out what other targets had been bombed during those raids.

 

[Linguofreak]

No, it was not even known that there was still a bomb left. It simply exploded.

Wow. I'm used to hearing about UXO finds with subsequent evacuations and controlled detonations in Germany, but this is the first time I've heard of an undiscovered, undisturbed bomb just going off randomly.

Article says it had buried itself 4m deep when it fell. Good thing it was deep enough not to be disturbed by plowing.

 

[Urwumpe]

Wow. I'm used to hearing about UXO finds with subsequent evacuations and controlled detonations in Germany, but this is the first time I've heard of an undiscovered, undisturbed bomb just going off randomly.

Yeah, but statistically, we have one such explosion every year. Most of the time they happen far away from civilization.



A local historian has now shed light on what was bombed there in WW2. There was an army radio station on the top of a hill there during WW2, that was bombed in Autumn 1943.

 

[Notebook]

Just had a look on the map and Limburg is quite a connection point to various cities.
Radio/Radar stations are more tactical targets. Any info why it was bombed? Or just a miss from the loco depot?

N.

 

[Urwumpe]

Just had a look on the map and Limburg is quite a connection point to various cities.
Radio/Radar stations are more tactical targets. Any info why it was bombed? Or just a miss from the loco depot?

N.

Can't find much except oral history from witnesses of WW2, but there had been two different radio stations that had been bombed in that place.


- A small mobile radio station was setup in the parish garden. That is fairly close to the bomb site.

- A large fixed radio station was in the forest of lower Hadamar. It was also the site of the last small ground combat between US forces and Germans during the liberation of Limburg. But that one is about 10 km away from the bomb today, somewhere west of Hadamar.





I am not sure if it was really a miss - those radio stations had been used to coordinate the air defenses, attacking them shortly before a bombing raid could really make it harder to coordinate fighters.

 

[jedidia]

New fun idea to lighten up my workday:

Write all class and property names in yeOldeEnglishe

 

[Notebook]

Re #25385 above.

I grew up in Blyth, North East England about 10 miles up the coast from Newcastle.
I never head of any UXB activity, I'm guessing all were sorted soon after the raids.

Newcastle was the target of a few raids, but not as heavily bombed as some cities:
https://en.wikipedia.org/wiki/Newcastle_Blitz

My parents where children then and don't recall any sustained bombing, but the Luftwaffe did seem keen on "Aerial Mines" or parachute bombs as they called them.
These single raiders went on for quite a while till near the end of the war.

When I was growing up the beach still had tank traps on it. 8' cubes of concrete scattered all over the sand-dunes. Of course it was obvious to small boys that you dug under them to make them roll over...Darwinism hadn't reached the North then.

Recently the Naval Gun Battery has been restored. It protected Blyth Harbour and beaches:
https://www.blythbattery.org.uk/

The gun type originally installed
https://en.wikipedia.org/wiki/BL_6-inch_Mk_VII_naval_gun
N.