6. Conclusion

Thermal-hydraulics must meet the challenges of fluid mechanics, i.e. achieve closure relationships that best model the phenomena. However, the coexistence of several phases in the flow makes this a highly complex task, given the multiple interactions between phases and the ever-changing interfaces. In the current state of knowledge, following a one-dimensional averaging approach, satisfactory models have been established and integrated into scientific calculation tools. These computational tools have reached a level of confidence and robustness that faithfully reproduces the large number of experiments carried out in support of nuclear power plant development. However, a detailed understanding of the phenomena involved is multidimensional, and is an essential step in achieving a high level of modeling. This requires sophisticated analysis, computing and experimental resources. Although computational...