{"id":372418,"date":"2024-07-17T14:48:48","date_gmt":"2024-07-17T14:48:48","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/strange-divergence-in-natural-circulation-simulation-simulation-using-vof\/"},"modified":"2024-07-17T14:48:48","modified_gmt":"2024-07-17T14:48:48","slug":"strange-divergence-in-natural-circulation-simulation-simulation-using-vof","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/strange-divergence-in-natural-circulation-simulation-simulation-using-vof\/","title":{"rendered":"Strange Divergence in natural circulation simulation simulation using VOF"},"content":{"rendered":"

Hi everyone, <\/p>\n

I’m a freshman doing transient simulation. I’m doing 2D tranient natural circulation simulation using VOF model. In the case, Water will be heated and generated vapor to drive the circulation. Model is shown below. <\/p>\n

<\/p>\n

 <\/p>\n

Firstly, solution converge and contour seemed reasonable. However, solution suddenly diverged with global courant number surged to 9322.7.  <\/p>\n

Discretization scheme and  residual and console is shown below. <\/p>\n

<\/p>\n

messages shown indicates that velocity field is abnormal and it did. Below velocity, volume fraction of vapor and  at last time step. <\/p>\n

<\/p>\n

I really have no idea that I have encountered the siuation when I run it again. <\/p>\n

I’m using Lee model and parameters used in the model is by default. Fixed e-4 time step is set. <\/p>\n

<\/p>\n

I’m really confused by the sudden ascending courant number and abrupt divergence. Any kind of suggestions would do me a great help<\/p>\n

 <\/p>\n","protected":false},"template":"","class_list":["post-372418","topic","type-topic","status-closed","hentry","topic-tag-c-vof","topic-tag-courant-number","topic-tag-fluent","topic-tag-transient"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t