Title

Numerical Investigations Of The Thermal Characteristics Of Lakes

Date of Award

1981

Availability

Article

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Mechanical Engineering

Abstract

A one-dimensional model for studying the thermal dynamics of cooling lakes has been developed. The model is essentially a set of partial differential equations which are solved by finite difference techniques. The model includes the effects of variation of cross-sectional area with depth, surface heating due to the solar radiation absorbed at the upper layer and internal heating due to the transmission of the unabsorbed solar radiation to sub-surface layers. The exchange of mechanical energy between the lake and the atmosphere is included through the influence of friction velocity on thermal diffusivity. The effects of discharge and intake by power plants are also included.The numerical model was calibrated by applying it to Cayuga lake in New York. The performance of the model was found to be excellent. The simulation covered one annual cycle. The model was then verified through a long term simulation using lake Keowee (South Carolina) data base. The simulation covered 9 years. The comparison between measured and predicted vertical temperature profiles was found to be good.The governing equations and associated boundary conditions were non-dimensionalized and analyzed. Five non-dimensional numbers were obtained and discussed. These numbers were then used in a numerical study of the stratification variability in sub-tropical cooling basins as a result of power plant heated discharge.

Keywords

Engineering, Mechanical

Link to Full Text

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