A wind tunnel study was performed to investigate how a dense gas plume could affect the mean flow and turbulence structure in a neutral boundary layer. Special consideration was given to make accurate velocity measurements within the dense-gas plume due to the sensitivity of hot-film (wire) antemometers to the dense gas (CO_2) concentration. The results of the experiments show that, in the presence of the dense-gas plume, the mean velocity profiles were changed significantly in shape near surface at low wind speeds. Consistently, singificant reductions in roughness lengths and friction velocities were also obsserved. Both the longitudinal and vertical turbulence intensities were found greatly reeduced in the presence of the dense-gas plume at low wind speeds. These changes and reductions were not only related to the magnitude of the dense-gas concentration, but also to the vertical extent of the desne-gas plume. The gradient Richardson number is shown to be the most appropriatee parameter for describing the changes in the mean flow and turbulence structure.
展开▼
