Anisotropy and Inhomogeneity Effects on Stable Atmospheric Surface Layer Flow Over an Aligned Obstacle Array
Abstract
In an effort to better understand flow in urban environments, velocity measurements were acquired within an aligned, large scale, obstacle array submerged in the atmospheric surface layer. Sonic anemometer measurements were acquired below the obstacle height at a number of locations downstream of the leading edge of the array in thermally stable conditions. After an initial deceleration due to the approach flow encountering the array, the flow was found to gradually accelerate with downstream distance. This result contradicts previous results on canopy layer flow in obstacle arrays. The behavior of the flow in the first few rows of the array was found to depend on upstream velocity. The velocity fluctuations were found to be more isotropic within the array for higher velocities, while lower flow velocities exhibited a tendency for the spanwise velocity fluctuations to be relatively stronger than axial fluctuations. Acceleration through the array is thought to cause the axial production term of the axial stress transport equation to become significant, transferring axial fluctuations to spanwise fluctuations.
- Publication:
-
APS Division of Fluid Dynamics Meeting Abstracts
- Pub Date:
- November 2002
- Bibcode:
- 2002APS..DFD.KH008N