REVISED DOUBLE PLUME MODEL -THE EVALUATION OF EFFECTIVENESS OF BUBBLE CIRCULATION COUNTERMEASURE-

Abstract

 We investigated the differences in the effects of the previous double plume model and the revised version on reservoir hydraulics and prevention of harmful cyanobacteria. Using the two-dimensional reservoir simulation model developed by JWA as a platform, the differences between the two double-plume models were evaluated in terms of their effectiveness in combating bubble circulation. As reported recently, the previous double plume model was developed focusing only on strong effects of density stratification compared to diffused bubble buoyancy. This paper presents the quantitative characteristics of overestimation of the far field surface horizontal flow quantity estimated by the previous model. Furthermore, due to these characteristics, numerical simulations under actual reservoir conditions revealed that the previous double plume model underestimated the surface layer retention time, an important habitat condition of harmful cyanobacteria and overestimated the preventive effects of the bubble circulation countermeasure. Finally, the lessons from the numerical simulation for the design and application of a countermeasure and future research topics for the bubble plume are discussed.