In this paper, the author derives a rephrased form of equations of conservation for a two-dimensional incompressible flow field inside a natural convection boundary layer.

The novelty of this work is the obtainment of an approximate analytical solution to the system of equations of mass and momentum conservation for natural convection boundary layer flows with the related boundary conditions, without the contribution of energy equation.

According to the adopted approach, there exists no distinction of the flow field as external or internal; hence this proposed method can be effective for both types of flow.

natural convection, buoyancy effect, boundary layer, Prandtl’s assumptions.