VT con mare formato

[mania2]

Citazione:TestaCuore ha scritto:

Citazione:volapiuk ha scritto:

mi pare sia stato ben spiegato che le polari (o, almeno, quello serie) tengono conto della corrente e dell'onda per quella condizione di vento.

relativamente al fatto che le VPP tengono conto del moto ondoso:

6.5 Added Resistance in Waves, RAW
The addition of an added resistance in waves (RAW) module to the VPP40 was brought about by the fact that cruising yachts, with outfitted interiors, were disadvantaged relative to their “stripped out” racing rivals. This is not surprising, since reducing the yacht’s moment of inertia by concentrating weight close to the centre of gravity will yield a performance gain when sailing in waves. The US Sailing funded project to introduce this feature into the VPP had three aims which tackled the fundamentals of predicting RAW :
1) Define a sea spectrum (wave energy density function) appropriate to the sailing venue
2) Devise a plausible and appropriately sensitive physical model of how parametric changes to the
yacht affect RAW when sailing in the sea state defined in 1
3) Devise a method by which a yacht’s pitch inertia could be determined directly by a physical test,
in the same way that stability is measured by an inclining test.

6.5.1 Wave Climate
As part of the research prior to introducing the RAW module, US Sailing funded the deployment of a
wave height measuring buoy at several popular sailing venues. The buoy was deployed during
typical races and the water surface elevations were recorded together with the wind speed.
On the basis of these measurements a single definition of wave climate was derived in the form of a wave energy spectrum normalised for a true wind speed of one knot. This approach has the merit that it is relatively easy to apply, because, whilst the significant height becomes a function of wind speed the modal period remains fixed at 5 seconds.
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