- A special S classification has been performed for the anemometer Thies First Class Advanced II to assess the classification value for all temperature range and as well for warm climate.
- This classification uses the same parameter as the A classification with exception of the temperature which is variable in the range -20 to +30°C.
The results obtained are:
Classification Report Thies First Class Advanced ll warm climate
| -20 °C | -15 °C | -10 °C | -5 °C | 0 °C | +5 °C | +10 °C | +15 °C | +20 °C | +25 °C | +30 °C | |
| Class S | 4.4 | 3.5 | 2.8 | 2.6 | 2.3 | 2.1 | 1.9 | 1.8 | 1.8 | 1.8 | 1.8 |
Table: Classification index Class s for different air temperatures
We notice that for all temperature ranges +15 to +30°C, the S classification value matches the A1,8 classification value “heating ON” of the anemometer Thies First Class Advanced II, see class A and class B uncertainty. This makes sense since warm temperatures have the same effect on the anemometer as the heating ON.
| Class A | Class B | |
| Heating ON or Temperature range +15°C … + 40°C | 1.8 | 2.0 |
| Heating OFF | 2.3 | 2.7 |
Source: Summary report AK 151023-1.2 Cup Anemometer Classification, Deutsche WindGuard Tunnel Services GmbH, Varel, Germany, 2017.
Impact:
Actually, the classification is linked to the uncertainty with the equation
where Uj is the wind speed bin; k the classification value.
For this reason the standard operational uncertainty is as follows:
| standard operational uncertainty by a wind speed of 10 m/s | Class A | Class B |
| Heating ON or Temperature range +15°C … + 40°C | 0.10 m/s | 0.12 m/s |
| Heating OFF | 0.13 m/s | 0.16 m/s |
