Development and validation of unstructured adaptive mesh technique for gas-liquid two-phase flows

Ito, Kei; Kunugi, Tomoaki*; Ohshima, Hiroyuki

For the purpose of direct numerical simulations of gas entrainment (GE) phenomenon in sodium-cooled fast reactors, a high-precision numerical simulation method for gas-liquid two-phase flows have been developed. To reproduce the GE phenomenon, the locality of the GE phenomenon has been addressed by developing an unstructured adaptive mesh technique by which high mesh resolutions can automatically applied transiently to the occurrence regions of the GE phenomenon. In this paper, the unstructured adaptive mesh technique was extended to two-phase flows. For that purpose, the redistribution algorithms for two-phase flow variables were developed based on the conservation laws of the variables. The unstructured adaptive mesh technique was validated by solving the well-known slotted-disk revolution and dam-break problems. As a result, the adaptive mesh technique succeeds in maintaining the slotted-disk shape after one revolution and resolving the dynamic dam-breaking behavior.