CATHENA Study of Two phase Water Hammer Inter-Peak Timing

Abstract

A development effort is underway to prepare CATHENA for use as a two-phase water hammer simulation tool. Preliminary investigations have shown that although the basic physics of water hammer is being modelled correctly by CATHENA, the inter-peak timing between pressure excursions in CATHENA simulations can be much larger than shown in the experimental data. In this paper, an effort is made to identify possible factors influencing the inter-peak riming, and their influence on the simulation results. The results show that the wall shear stress calculation in CATHENA must be adjusted to properly account for unsteady wall shear stress under accelerating and decelerating flow conditions.