G107 On the Difference Between Mean Velocity Profiles on the Turbulent Boundary Layer and the Channel Flow

Abstract

Many researches of the wall bounded turbulent flow have been performed so far. However, the differences between mean velocity profiles (MVP) in turbulent boundary layer (TBL), channel and pipe flow are not sufficiently understood. It is traditionally considered that the outer region of MVP has unique profile but the inner region is collapsed with one another. In this study, we define a new region named Quasi Logarithmic Region (QLR). QLR is another universal region which satisfies approximately log-law profile and is different from classical log-region in the MVP. We present the difference between MVPs in the TBL and channel flow using QLR. It is found that von Karman constant is 0.41 in the TBL flow but is 0.43 in channel flow under the low Reynolds number conditions. This implies that outer flow condition affects on the inner region.