For the flat terrain covered by roughness blocks, three different occupancy rates (25.0%, 12.5% and 5.6%) were examined.
Roughness blocks whose heights were one eighth of the hill height were arranged in a staggered pattern with a roughness density of 4.1% to model the rough conditions.
Adding or removing roughness blocks on the hill surface or inflow area changes the velocity deficit and creates a completely different turbulence structure in the wake.
The effects of the roughness blocks were clarified by comparing the flow characteristics over hill models, with emphasis on speedup ratio and turbulence structure.
The results show that the roughness blocks both on the hill surface and on the upstream ground affect the speed-up ratio over the hill.
In this study, (a) flat terrain covered by roughness blocks, (b) flat terrain covered by vegetation, (c) a 3-D hill covered by vegetation, and (d) a real forest covered complex terrain, were modeled step by step.
Wind tunnel experiments were carried out to investigate the effects of roughness blocks on the atmospheric boundary layer flow over a two-dimensional low hill with maximum slope 0.21.
The main purposes of this study are to generate a large turbulence scale and simulate a turbulent flow fitted to specified power spectrum and co-coherence in a low frequency range, both of which are not easily accomplished only by the means of roughness blocks, spires and grids.
3D coordinates extraction, 3D distances and area measurement, planar best-fit for discontinuity orientation, directional roughness profiles, block size estimation, and other tools have been experimented on a calcareous quarry in the French Alps.
Atomic force microscopy images of PS-b-PMMA films having thickness similar to the domain periodicity permitted us to study the effects of substrate roughness and block affinity on domain orientation.
