This　paper　provides　a　numerical　simulation　to　explore　natural　convection　and　fluid　flow　in　a　three-dimensional　wavy　cubical　enclosure　subjected　to　a　magnetic　field　along　the　z-axis.　The　main　emphasis　of　this　research　is　to　discuss　entropy　generation　inside　a　wavy　porous　cavity.　Brinkman＇s　extended　non-Darcy　flow　model　is　utilized　for　studying　the　free　convection　in　the　permeable　medium.　The　equations　of　the　mathematical　model　were　solved　using　Galerkin　finite　element　method.　Isotherms,　streamlines,　velocity　profile,　and　variation　of　average　Nusselt　number　are　calculated　for　various　values　of　Ra　(103–106),　Ha　(0–100),　and　φ　(0–0.08).　The　results　show　that　the　streamlines　and　isotherms　increase　with　the　increase　of　Darcy　and　Rayleigh　numbers.　Besides,　entropy　generation　is　sensitive　to　the　values　of　Darcy　number,　Rayleigh　number,　Hartmann　number,　and　the　number　of　undulations.　Besides,　the　variation　of　the　Nusselt　number　is　affected　by　the　Rayleigh　number　and　Darcy　number.　The　highest　Nusselt　number　can　be　obtained　for　a　maximum　number　of　undulations　only　at　the　small　values　of　the　Rayleigh　number.　Otherwise,　this　pattern　will　be　changed　in　the　opposite　trend　at　large　values　of　the　Rayleigh　number.　At　the　highest　values　of　Ra,　increasing　Ha　from　0　to　100　decreased　Nuavg　by　23%,　while　increasing　Da　from　10−5　to　10−2　enhanced　it　by　177%.　Finally,　it　was　found　that　the　values　of　Beavg　are　only　being　enhanced　by　only　one　parameter,　namely　the　Hartmann　number.　The　obtained　results　from　the　current　non-Darcy　flow　model　agree　well　with　the　available　literature　results.　©　2023　Elsevier　B.V.