On the Comparison of Flow Physics between Minimal and Extended Flow Units in Turbulent Channels

Direct numerical simulations were performed to study the effects of domain size a minimal flow unit (MFU) and its inherent periodic boundary conditions on physics turbulent channel in range 200≤Reτ≤1000. This was accomplished by comparing statistics with those computed sub-domains (SD) extended simulations. The dimensions MFU SD matched, dynamics set minimize artificial periodicities. Streamwise spanwise healthy MFUs found increase linearly Reynolds number. It also that both good agreement. suggests represent extended-domain well up Reτ=1000, indicating nearly negligible effect MFUs. However, there small deviation within buffer layer for at Reτ=200, which manifested an increased mean velocity tail Q2 quadrant u′-v′ plane. Thus, it should be noted when considering size, stricter criteria may need put place ensure dynamics.