Ruochuan Gu

Validation of cold climate lake temperature simulation

Abstract A detailed data set of water temperature profiles, ice thicknesses, snow depths, and weather parameters collected on an urban Minnesota lake is reported and compared to simulations with a one-dimensional, unsteady heat transfer model.

Jet Mixing in Lake or Reservoir Stratification Simulations

ABSTRACT MINLAKE, a dynamic, one-dimensional, unsteady lake water stratification simulation model has been extended by a water jet mixing submodel (JETMIX). The model is intended primarily to evaluate lake management and control strategies. The extended model simulates the continuous change of lake stratification in response to artificial mixing induced by water jets and natural mixing by wind and cooling. Artificially forced summer destratification with a recirculating pump/jet discharge system, and a warm water jet discharged into an ice-covered lake were studied. Numerical results were obtained to predict the effect of jet mixing on the evolution of water temperature and dissolved oxygen profiles in time. The effect of the warm water jet discharge on the ice cover was of particular interest. The simulation model was verified with laboratory experimental data. The capabilities and applicability of the model were illustrated with simulations of a hypothetical summer destratification and a planned winter ...

Submerged warm water jet discharge in an ice-covered reservoir or lake

Abstract A submerged warm water jet discharge into an ice-covered lake or reservoir is investigated by one-dimensional and two-dimensional flow and heat transfer simulation. A one-dimensional jet integral model combined with a one-dimensional, unsteady heat transfer model for a natural lake is used to predict jet trajectories and vertical temperature distributions in the receiving water under an ice cover. A two-dimensional and unsteady flow and temperature simulation is made by solving the Reynolds equations with a buoyancy-modified κ-ϵ model for closure. The results of both 1-D and 2-D simulations show the great significance of buoyancy effects on the jets. The progressive mixing and warming of the initially stratified (0° to 4°C) ambient water are illustrated. Feedback from changing ambient conditions changes buoyancy forces acting on the jet dramatically. Buoyancy reversal is illustrated for jets discharged at initial temperatures from 8° to 15°C, as the jets become diluted by entrainment of colder ambient water. Ice covers are affected by this reversal. Jet discharge temperature and ambient water depletion are shown to be the most important factors controlling the behavior of submerged water jet discharges into ice-covered reservoirs or lakes.