Loading...

Evaluation of Turbulent Mixing in Lake Gull Using Numerical Modeling and Comparison with Field Data

Rafiee, Fatemeh | 2024

0 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 57301 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Safaie, Ammar
  7. Abstract:
  8. Vertical turbulent mixing in lakes plays a critical role in the distribution and transfer of nutrients, oxygen, and heat, significantly impacting lake productivity and the growth of algae and aquatic plants. During summer, the persistent and intense solar radiation creates a thermal stratification in lakes, which inhibits deep vertical mixing. In stratified lakes and oceans, small-scale mixing processes are key drivers of vertical fluxes that transport particles and substances, including nutrients, pollutants, and microorganisms. Despite the significant influence of small-scale turbulent mixing, numerical models of stratified lakes often neglect these effects due to the challenges associated with accurately modeling them. This study aims to compare and analyze turbulent mixing in a stratified lake by calculating the depth-dependent turbulent diffusion coefficient (Kz) and examining thermal stratification structures at various length scales. A one-dimensional turbulent mixing model, GOTM, is used for numerical modeling. Field data from the SCAMP device, collected in 2014 in Lake Gull, Michigan, USA, is employed in this research. The results show that the logarithm of the turbulent diffusion coefficient (Kz) is approximately -5.5 in strongly stratified regions of the lake and increases to about -3.5 in regions with more mixing. Additionally, the study uses the D index, derived from the relationship between different length scales and the number of mixing layers, to assess the intensity of thermal stratification over time. Finally, numerical modeling with the GOTM turbulent mixing model, along with the calibration of related turbulent mixing parameters, shows good agreement with observed temperature and salinity profiles in the lake. These results can be used in conjunction with three-dimensional hydrodynamic models to incorporate the impacts of turbulent mixing
  9. Keywords:
  10. Thermal Stratification ; Self-Contained Autonomous MicroProfiler (SCAMP)Field Data ; Turbulent Mixing ; Gull Lake ; Generalized Ocean Turbulence Model (GOTM)Turbulent Mixing Model ; Numerical Modeling

 Digital Object List

 Bookmark

No TOC