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TDG Prediction

An illustration of TDG downstream of a dam.

An illustration of TDG downstream of a dam.

Over the years, serious efforts have been made to develop a reliable numerical model to predict TDG downstream of spillways. The development of a reliable predictive numerical tool can be achieved only if transport, mixing, production and degasification of TDG can be adequately modeled.

Computation of transport and mixing of TDG requires accurate modeling of the hydrodynamics in the tailrace. In particular, the attraction of ambient water by surface jets must be predicted since it might dilute the spillway region close to the powerhouse but also has the potential to increase the resulting TDG downstream of a dam due to additional water entrained into the aerated zone.

The TDG production depends on pressure, temperature and interfacial area of the bubbles. Bubble interfacial area is determined by complex processes such as air entrainment, bubble breakup and coalescence, pressure, and mass transfer between bubbles and water.

Last modified on September 26th, 2012
Posted on March 14th, 2012