2013 Chinese GP - Shanghai

[godlameroso]

Post Thu Mar 28, 2013 6:37 pm

My weather prediction, a perfect weather(for Shanghai) weekend. Perhaps overnight rain on one of the days, but temps will be around 24-28 C Track about 33. This race will show us who's where really.

[Nando]

Pretty sure it´s the opposite.

Blowing south (or south west-ish) means head wind. Surely that would mean less drag with a head wind.

Eh? A head wind down the straight means that the wings have a higher air speed, and hence produce both more DF and drag.

My mistake, mixed up head wind with tail wind.

Basically what i was getting at is if the car is travelling south and the wind is blowing south there´s less resistance on the long straight.

And not "It means enormous downforce and drag down the straight" since the wind is blowing in the same direction the car is travelling at if the wind is blowing south.

[beelsebob]

Pretty sure it´s the opposite.

Blowing south (or south west-ish) means head wind. Surely that would mean less drag with a head wind.

Eh? A head wind down the straight means that the wings have a higher air speed, and hence produce both more DF and drag.

My mistake, mixed up head wind with tail wind.

Basically what i was getting at is if the car is travelling south and the wind is blowing south there´s less resistance on the long straight.

And not "It means enormous downforce and drag down the straight" since the wind is blowing in the same direction the car is travelling at if the wind is blowing south.

Right, the key is that the wind is blowing *from the* south, not blowing south.

[Richard]

I think wind directions were invented by agrarian societies that wanted to know what the wind brought , they didn’t care where it was going. For example what is important for a farmer in the northern hemisphere is that winds from the south bring warm air, and the north brings cold air.

One could wonder why societies dependant on sail didn’t name winds based on where they would go. However I suspect the same thing applies, sailors want to know the wind characteristics and that is dictated by where the wind has come from.

[godlameroso]

Wind doesn't blow in a direction it circulates from a direction, the difference is subtle, keep that in mind. What might be a tailwind through 3/4ths of the back straight may be a side wind before the breaking zone.

[beelsebob]

Wind doesn't blow in a direction it circulates from a direction, the difference is subtle, keep that in mind. What might be a tailwind through 3/4ths of the back straight may be a side wind before the breaking zone.

The size of the circulations you're talking about are so large that for the purpose of a race track, it blows from a direction. Circles thousands of miles across are effectively straight lines on the 1-2 mile scale.

Note – of course small variations, (or even large local variations) occur, due to the wind being funneled through or sheered around buildings, but that does not mean that the general trend is for a circular pattern over the circuit.

[dren]

We might see a Lotus resurgence here. Mclaren will be in the mix too. Should be a close race.

[seventhsin]

Has Nando aligned the S marker with the south direction? Or the direction blowing to?

As above, weather forecasts always say something 'winds 4knots blowing south easterly' and yeah its the direction it's blowing from

[beelsebob]

Has Nando aligned the S marker with the south direction? Or the direction blowing to?

As above, weather forecasts always say something 'winds 4knots blowing south easterly' and yeah its the direction it's blowing from

The S marker is at the south of the map. The wind is forecast to be blowing against the cars as they drive down the main straight.

[FrukostScones]

my forecast says 18-22 C over the race weekend.
With this temps it should be an easy Lotus 1-2.

[godlameroso]

Wind doesn't blow in a direction it circulates from a direction, the difference is subtle, keep that in mind. What might be a tailwind through 3/4ths of the back straight may be a side wind before the breaking zone.

The size of the circulations you're talking about are so large that for the purpose of a race track, it blows from a direction. Circles thousands of miles across are effectively straight lines on the 1-2 mile scale.

Note – of course small variations, (or even large local variations) occur, due to the wind being funneled through or sheered around buildings, but that does not mean that the general trend is for a circular pattern over the circuit.

All the data I'm privy to says otherwise, there is always localized eddy and vortex formation in air masses that can cause partial shearing forces in the overall flow direction in even unobstructed flow(thus a tail wind can become a side or even head wind temporarily). The statistically relevant flow of air can remain constant for hundreds of miles, but there will always be localized shifts. This is even observed in laboratory conditions in essentially closed loop air tunnels and can throw air tunnel data off. We noticed the effect was even greater when the pressure distribution in the tunnel wasn't uniform(the nature of a wind tunnel makes completely uniform pressure impossible). Once the tunnel pressure was stabilized to the maximum we could muster the effects were mitigated somewhat, but I digress, that is whole 'nother can-o-worms.

For one, China's mountainous topography easily causes pressure gradients that can affect overall wind patterns. Also to some small but important effect is the increased air density caused by pollution, and the way the sun interacts with the track as the haze changes the refraction of the sun and the way it interacts with the track. Typically the China race has a very minimal delta with ambient to track temperature compared to say Barcelona, or Germany.

[dave34m]

Do drivers like this circuit? It has never really grabbed me as a viewer. That 1st corner is interesting on the opening lap but after that it just becomes painfully slow and it just keeps turning forever.

[godlameroso]

From a purely driving perspective it's definitely an interesting challenge. The corners are all very tricky to get perfect, take the first sequence of turns, it's really 4 turns and it goes right then left but you have to treat it as one turn to get the best line, not to mention the angle of the turn makes it hard to put the power down on exit. Turns 7 and 8 are great high speed turns, which lead to a double apex left hander, of which it's hard to balance the exit, and it's so crucial to nail it as well. Then the long unwinding right hander, there are multiple lines available which makes it for good racing as it leads to the long back straight. Then the slowest part of the track, again very trick because the road changes width after the hairpin making the exit more complicated.

Even the last turn is rather tricky because the apex is so difficult to spot.

[Nando]

It´s very very technical but it do share some traits with Malaysia.

T1 and 2 is almost identical but with a much bigger radius for T1 at China.
Then you have the high speed left/right handers. (which can also be seen in Abu Dhabi and probably other Tilke-tracks)

[Gridlock]

Then you have the high speed left/right handers. (which can also be seen in Abu Dhabi and probably other Tilke-tracks)

Yeah, he really broke the mould when he sat down to draw his tracks.



I like China to drive, virtually, but not so much to watch.