Effect of surface radiation on natural convective flows and onset of flow reversal in asymmetrically heated vertical channels

► Combined surface radiation and natural convection is numerically investigated for laminar air flow. ► Variable property effects are accounted for. Comparisons with experimental data are provided. ► Surface radiation deletes the onset of recirculations at the top of the channel. Comparisons with methods used for decoupling the two transfer modes are discussed. ► For maximum temperature differences less than 200 K, the influences of temperature dependence properties are weak.