Computational Fluid Dynamics Framework for Turbine Biological Performance Assessment

Over the past decade, there have been many studies describing injury mechanisms associated with turbine passage, the response of various fish species to these mechanisms, and the probability of survival through specific dams under certain conditions.  However, transforming and integrating these data into tools to design turbines that improve survival by minimizing impacts to fish during passage has been difficult and slow. Although identifying the locations and hydraulic conditions where injuries occur is challenging, a more robust quantification of the turbine environment has emerged through integrating balloon tag, sensor fish data, and CFD studies. Field-testing new designs is very expensive, so tools that improve the linkage between fish injury data and turbine characteristics are needed to identify the most promising designs.  In this presentation, a method for turbine biological performance assessment is introduced to bridge the gap between field and laboratory studies on fish injury and turbine design.  Using this method, a suite of biological performance indicators is computed based on simulated data from a computational fluid dynamics (CFD) model of a proposed turbine design.  Each performance indicator is a measure of the probability of exposure to a certain dose of an injury mechanism.  If the relationship between the dose of an injury mechanism and frequency of injury (dose–response) is known from laboratory or field studies, the likelihood of fish injury for a turbine design can be computed from the performance indicator.  By comparing the values of the indicators from various turbine designs, the engineer can identify the more-promising designs.  Discussion here is focused on Kaplan-type turbines, although the method could be extended to other designs. Following the description of the general methodology, we will present sample risk assessment calculations based on CFD data from models of the John Day Dam and Wanapum Dam turbines.