Surface roughness and thermal stratification effects on the flow behind a twodimensional fence—I. Field study
Abstract
A smallscale field study was conducted to investigate the flow around a twodimensional fence which was placed perpendicular to the oncoming flow. Characteristics of the oncoming flow and flow behind the fence were measured and, in addition, the flow behind the model was visualized with small wind vanes. The turbulent Reynolds number ( Re _{turb} = UH/K, where U is the mean velocity at model height H and K is the turbulent diffusivity) and flux Richardson number at the model height are chosen as the characteristic nondimensional numbers for the oncoming flow. These nondimensional numbers, derived from the normalized momentum and energy equations, are useful and convenient when comparing the field and wind tunnel data for similarity. The cavity wake length L_{c} (chosen as flow characteristic) normalized by the model height H, L _{c}/H, was found to increase as Re_{turb} increases. The effects of thermal stratification are unclear for the range of weak stratification tested. For such cases, the effect of the (weak) stratification is probably felt indirectly through its effect on the turbulence. These results will later serve as input and comparative data for a related wind tunnel study (Ogawa and Diosey, 1980) which will investigate the similarity criteria required for laboratory simulation of such phenomena.
 Publication:

Atmospheric Environment
 Pub Date:
 1980
 DOI:
 10.1016/00046981(80)902310
 Bibcode:
 1980AtmEn..14.1301O
 Keywords:

 Air Pollution;
 Atmospheric Stratification;
 Fences (Barriers);
 Ground Wind;
 Pollution Transport;
 Surface Roughness Effects;
 Wind Tunnel Tests;
 Flow Distortion;
 Temperature Gradients;
 Wind Velocity;
 Fluid Mechanics and Heat Transfer