This paper analyzes the fluid and heat flow within entrapped porous triangular cavities involving various thermal boundary conditions (case 1: hot horizontal walls and cold inclined walls; case 2: cold horizontal walls and hot inclined walls). Finite element based numerical study has been performed for various values of Prandtl number (Prm=0.026 and 7.2), Darcy number (Dam=10-4-10-2), Reynolds number (Re=1-1000) at a high value of Grashof number (Gr=105). The upper cavity for the case 1 and the lower cavity for the case 2 show almost similar trends and vice versa based on the exact opposite thermal boundary conditions. Heat transfer is conduction dominant at Dam=10-4involving both Prmwhereas, convection heat transfer dominates at Dam=10-2especially for Prm=7.2. Although the motion of the horizontal walls significantly influences the fluid flow field within the cavities, due to the decoupling between the fluid and thermal fields at the low Pem(Pem=0.026,0.26 and 2.6), conduction dominant heat transfer occurs. At the high Damand Prm=7.2, a pair of symmetric streamline or heatline cells are seen for Re≤1 whereas, a bigger primary streamline or heatline cell is accompanied by a secondary streamline or heatline cell for 1⩽Re≤100. At 500⩽Re⩽1000, the single larger streamlines or heatline cells are seen especially for Prm=7.2 involving Dam=10-2. At Prm=0.026, the average heat transfer rates (Nut‾,Nub‾, Nul‾ and Nur‾) are almost constant with Re and Dam. At Prm=7.2, the larger magnitudes ofNut‾ and Nul‾ are observed for Re≤10 compared to those for Re=100 involving Dam⩾10-3whereas, the magnitudes of Nur‾ are almost similar for all Re involving all Damin the upper cavity (case 1) within Re⩽100. In the lower cavity (case 1), the magnitudes of Nub‾ and Nur‾ are larger for Re=100 whereas, the magnitudes of Nul‾ are larger for Re≤1 for almost entire range of Damwithin Re≤100 involving Prm=7.2. The average Nusselt numbers are significantly larger at the high Re (Re=500 and 1000) involving all Dam(except for the horizontal walls involving Dam⩽8×10-4) in the cases 1 and 2 at Prm=7.2. © 2016 Elsevier Ltd