Prandtl’s Secondary Flows of the Second Kind. Problems of Description, Prediction, and Simulation

Abstract— The occurrence of turbulent pulsations in straight pipes noncircular cross-section leads to the situation, when average velocity field includes not only longitudinal component but also transverse components that form a secondary flow. This hydrodynamic phenomenon discovered at twenties last century (J. Nikuradse, L. Prandtl) has been object active research present day. intensity flows is high; usually, it greater than 2–3% characteristic flow velocity. Nevertheless, their contribution processes transfer momentum and heat comparable pulsations. In this paper, review experimental, theoretical, numerical studies channels given. Emphasis placed on issues revealing physical mechanisms formation developing models apriori assessment forms. specific features development open with inhomogeneously rough walls are touched upon. approaches semiempirical simulation presence discussed.