Numerical study of the airflow over forest clearings

Oxford

2008

S. 259-277

18 Abb., 3 Tab., 33 Lit. Ang.

Artikel aus einer ZeitschriftUnselbständiges Werk

200150085

In order to better understand the behaviour of the turbulent flow around forests interrupted by clearings, numerical simulations with a LVEL k-{epsilon} turbulence model have been performed. The effects of the clearing width on the flow field were studied for two-dimensional forest-clearing-forest sequences. Furthermore, three-dimensional calculations were conducted in order to investigate the influence of the clearing shape. The numerical results were validated against our own wind tunnel data. The impact of the clearing width on the flow field is marginal above and within the upstream forest area, but significant further downwind. With increasing clearing width, the volume flux through the downstream forest and the streamline patterns resemble more and more those of an individual forest stand. For the forest configuration with maximum investigated clearing width (a/H = 11, where H is the forest height), the flow around the forest downstream of the clearing is still clearly affected by the presence of the upstream forest area. With increasing clearing width, the mean bending moment coefficients of trees standing near the leeward clearing edges increase gradually. For small clearings, the influence of clearing shape (round or rectangular) on the flow field is marginal.