Saber Yekani Motlagh - Assistant Professor, Urmia University of Technology, Department of Mechanical Engineering, Urmia, Iran
Salar Taghizadeh - Master Student, Urmia University of Technology, Department of Mechanical Engineering, Urmia, Iran
Hosseinali Soltanipour - PhD Student, Urmia University, Department of Mechanical Engineering, Urmia, Iran.

This paper presents a numerical investigation of mixed convection in a square lid driven cavity with a rib mounted on hot wall. Flow in the cavity is considered as 2D, steady and laminar. The variation of fluid density is approximated using Boussinesq model. Computations are done by solving continuity, Navier-Stokes and energy equations using finite volume method. The effects of rib height and thickness on heat transfer rate are examined in a wide range of Reynolds number and for three Richardson numbers i.e. Ri=0.5, 1 and 2. It is observed that when Richardson number is kept constant, by increasing both Reynolds and Grashof numbers, the Nusselt experiences a sudden drop and with the use of ribs, it is possible to delay this unexpected trend to higher Reynolds numbers. Numerical results reveal that rib can increase or decrease the average Nusselt number depending on rib size, Reynolds and Richardson numbers.

Heat transfer, Lid driven cavity, Nusselt number, rib