Abstract: To make balance between numerical accuracy and computational efficiency,a deferred correction method coupled with high order scheme is proposed for computation of convection flux.Classical benchmark problems,cavity driven flow with high Reynolds numbers,are solved numerically to verify precision and stability of the method.Finally,the method is used to solve Boussinesq fluid of natural convection heat transfer.It shows that the method overcomes numerical divergence effectively in high Rayleigh number problem.It captures accurately isothermal lines and stream lines at different eccentricities in natural convection heat transfer.

Key words: unstructured, natural convection heat transfer, Boussinesq fluid