Author(s): Akira Murota; Kohji Michioku
Linked Author(s): Kohji Michioku
Keywords: No Keywords
Abstract: To examine the contribution of external thermal and dynamic energies, such as surface wind stress, thermal convection and inflow and outflow discharges, to the destratif ication process in reservoirs, the authors carried out a year-long field survey of temperature fields at the upper reservoir of a pumped storage plant. The field data provides insight into the effects of meteorological and hydrological factors on the formation and deformation of thermal strata. The reservoir undergoes two distinct thermal cycles: (1) During the heating period, l. e., spring to summer, the advective process, resulting from successive pumped storage operation, predominantly effects the thermal structure. (2) During the cooling season, i. e., fall through winter, the discharge- to- volume ratio is radically reduced by the, absence' of the一turbine operation; .. thu. . therma. .. convec. t. ion. .. gain. .. relative. . importance. . ln. .. the. . thermoc line. . descending process. . By. . the. action of pumping and power generation, as well as by the surface heat-exchange process, distinct thermoclines develop and thus the temperature field presents a typical layer structure. Based on the field data, we develop a mathematical model for the prediction of the temperature fields in reservolrs. The model is formed paying. attention on the mechanically and thermally induced vertical mixing process. It is demonstrated that, despite the simplicity of the model, the present analysis is. capable of accurately reproducing field' measurement of thermal structure. We wish to emphasize that the model reasonablly predicts the thermocline descending and the resulting turnover process which have never been successfully predicted by any prevlous models.
Year: 1985