DNS vs coarse meshes of a mixed convection in a 3D ventilated cavity

Direct numerical simulation of a mixed convection turbulent flow in a 3D ventilated cavity. The configuration resembles the experimental set-up performed by Blay et al. [1]: namely, the domain is a square cross-section with a depth aspect ratio of D/H=0.3. Cold air enters the cavity through a thin inlet slot at the top of the left wall with a laminar (Poiseuille flow) velocity profile. The inlet slot has an aspect ratio Lin/H=. The air is discharged through the outlet slot with an aspect ratio of Lout/H= at the bottom of the right wall. The cavity is filled with air (Pr = ) at Rayleigh number based on the cavity height Ra=. Froude number based on the inlet height, Lin, is equal to Fr= and the Reynolds number based on the the inlet height is equal to Re=684. Convective boundary condition are used at the outflow. The four closing walls are isothermal (bottom wall is hot whereas the rest are cold) with no-slip boundary conditions for velocity. Periodic boundary conditions are imposed in th