In this article the natural convection of nano-fluid water - copper in a square cavity has been studied numerically. The left wall is maintained at high temperature . right wall is maintained at low temperature and the other walls are adiabatic. The numerical model is based on the SIMPLE algorithm is used to solve the equations of continuity. https://www.lightemupsequences.com/mega-pick-Danger-Area-Under-Construction-Do-Not-Enter-mega-offer/