Plume merger from area sources*

Rising temperatures pose a threat to industrial projects requiring cooling. At large-scale, cooling is often provided by wet cooling towers. Water vapor is then discharged to the atmosphere where, depending on ambient conditions, it may condense to form a visible plume. Because such plumes are generally undesirable, major investments have been made into abatement technologies. However, any successful deployment of these technologies requires an understanding of plume merger and its impact on entrainment. Previous theoretical work on plume merger has used velocity potential contours to mark the boundary between the plume interior vs. exterior. Analyses are performed in the point source limit where the plume source is small. We propose a modification that allows plumes to originate from sources of arbitrary size. We study merger in three contexts: (i) two plumes placed side-by-side, (ii) two parallel rows of plumes in a quiescent environment, (iii) a single row of plumes in a crosswind. In the former case, comparisons are drawn with a classical and purely-geometric description of plume merger. In the latter case, comparisons are drawn against existing tow tank experimental data. Results of these comparisons and implications for industrial-scale plume abatement are discussed.