Summary:
In this study natural convection in air-filled rectangular cavity is studied numerically by two commercial CFD codes. Numerical simulations are carried out for air and water for different aspect ratios and wall temperatures. Calculations are compared with experimental correlations in the literature and with each other. Calculation time and mesh number therefore used GPU are the main parameters considered in this study. According to the numerical results SIMCENTER FLOEFD is an effective CFD code as ANSYS FLUENT and gives accurate results for this type of problems.