Thank you very much for your reply. But I need some more clarifications, as in my case, the bubble will be formed within the fluid domain due to pressure difference and shape of the geometry. So initially the whole domain will be filled by water, later as the flow occurs vapour will be generated in the low-pressure region and it will be carried along with the flow and collapse at the high-pressure region. So should I need to create the multi-fluid volumes? And also I was not able to access the link attached above.