The Challenge: Moving Beyond $Pr = 1$
When performing Large Eddy Simulations (LES) around a 3D circular cylinder, achieving a validated solution for $Pr = 1$ is a great milestone. However, increasing the Prandtl number to $Pr = 2$ introduces a tighter constraint on your thermal resolution. While the momentum mesh (velocity field) remains the same, the thermal scales shrink.
If your mesh is just fine enough to resolve 80% of the Turbulent Kinetic Energy (TKE), it might fail to resolve the same percentage of the Thermal Variance (Scalar Energy) because the thermal dissipation occurs at smaller scales when $Pr > 1$.
