Wall y+ Strategy for Dealing with Wall-bounded Turbulent Flows

A strategy for dealing with turbulent flows over a two dimensional surface mounted obstacle using the wall y(+) as guidance in selecting the appropriate grid configuration and corresponding turbulence models are investigated using Fluent. The CFD results were compared with experimental data from Zeidan's Turbulent Shear Recovery behind Obstacles on Smooth and Rough Surfaces. Both undisturbed and disturbed (over ridge) flows are studied. For both cases, a wall y(+) in the range of 30 to 60 is determined to be sufficiently accurate, where the log-law region is resolved. It is also advisable to avoid having the wall-adjacent mesh in the buffer region since neither wall functions nor near-wall modeling approach accounts for it accurately. RSM predicts the flow properties more consistently because it accounts for all the Reynolds Stress components.