The method of thwaites ppt1/1/2023 ![]() ![]() Because of the slow approach of the velocity to the free stream, different conventions used to define the thickness lead to different values of R τ assigned to a given flow. It is a little unusual to use R τ for the boundary layer since it requires that the velocity profile be cutoff using an arbitrarily defined overall boundary layer thickness, δ. The primary measure of the Reynolds number used in this work is the friction Reynolds number R τ = u τ δ / ν. ![]() ![]() At a low Reynolds number, the profile approaches the laminar channel/pipe flow limit. More recently, the same profile was shown to accurately approximate velocity profiles in channel flow, the zero pressure gradient boundary layer, and the boundary layer in an adverse pressure gradient The universal velocity profile is uniformly valid from the wall to the free stream at all Reynolds numbers from zero to infinity. A recently developed mixing length model of the turbulent shearing stress has been shown to generate a universal velocity profile that provides an accurate approximation to incompressible pipe flow velocity profiles over a wide Reynolds number range. ![]()
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