Drag Reduction via Phase Randomization in Turbulent Pipe Flow

In this study, possibility of reducing drag in turbulent pipe flow via phase randomization is investigated. Phase randomization is a passive drag reduction mechanism, the main idea behind which is, reduction in drag can be obtained via distrupting the wave-like structures present in the flow. To facilitate the investigation flow in a circular cylindrical pipe is simulated numerically. DNS (direct numerical simulation) approach is used with a solenoidal spectral formulation, hence the continuity equation is automatically satisfied (Tugluk and Tarman, Acta Mech 223(5):921–935, 2012). Simulations are performed for flow driven by a constant mass flux, at a bulk Reynolds number (Re) of 4900. Legendre polynomials are used in constructing the solenoidal basis functions employed in the numerical method.