**5. Conclusions**

A numerical model is developed to understand the effect of surface roughness elements on the evolution of stratification and self pressurization. The Volume of Fluid (VOF) method is used to predict the liquid–vapor interface movement, and the Lee phase change model is adopted for evaporation and condensation calculations. From previous studies, it is observed that the shape of the inner wall surface of the storage tank plays an essential role in the development of the stratified layer. Using the computational model developed, a detailed study has been conducted on a cylindrical storage tank with an iso grid and rib structure. The major conclusions are:

