Aerodynamic studies at Thetford forest
Measurements of wind speed were made within and above a 16 metre pine forest with sensitive anemometers linked to a computer controlled data acquisition system. The considerable interference of the supporting tower on the airflow was determined. The zero plane displacement, d, was about 12 metres. P...
| Main Author: | |
|---|---|
| Published: |
University of Reading
1974
|
| Subjects: | |
| Online Access: | http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.645989 |
| Summary: | Measurements of wind speed were made within and above a 16 metre pine forest with sensitive anemometers linked to a computer controlled data acquisition system. The considerable interference of the supporting tower on the airflow was determined. The zero plane displacement, d, was about 12 metres. Profiles above the canopy approximated to a pure logarithmic form with a roughness length of about 1 metre. The applicability of the log-linear and power profile equations was investigated. One minute speed fluctuations showed a progressive decoupling with height with increasing stability. Swaying in strong gusts is thought to cause progressive loosening of the soil-root complex in extreme cases resulting in windthrow. The canopy wind profile followed the theoretical form fairly closely with the canopy top eddy approximating to 0.4 (tree height - d). A mean wind direction shift through the canopy of 270 was measured. The bulge often found in the trunk space wind profile is explained in terms of convective processes; smoke trails confirming the existence of convective plumes. |
|---|