PANS SIMULATIONS: LOW VERSUS HIGH REYNOLDS NUMBER APPROACH

Different approaches for specifying the ratio of modelled-to-total dissipation (f(epsilon)) in the PANS model, based on the k - omega SST model, are evaluated for different ratios of the modelled-to-total kinetic energy, f(k). Based on theoretical reasoning it is argued that applying f(epsilon) = a center dot f(k) should have little effect, and that fe = fk is not expected to improve the results. This is confirmed by applying the approaches to a turbulent channel flow at R-e tau = 395 and 180, and comparing the results to the often used 'high Reynolds number' approach (f(epsilon) = 1.0). Reducing f(epsilon) leads to a reduction in range of scales in the flow; dissipation is allowed at larger scales and therefore smaller scales are suppressed.