Low Reynolds Number Multiple-Time-Scale Turbulence Model and Calculations of Steady and Pulsating Shear Layers

Download or read book Low Reynolds Number Multiple-Time-Scale Turbulence Model and Calculations of Steady and Pulsating Shear Layers written by National Aeronautics and Space Adm Nasa and published by . This book was released on 2018-10-21 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: A low Reynolds number multiple-time-scale turbulence model (LMS) and its application to fully developed turbulent channel flows and pulsating pipe flows are presented. The LMS can describe the inequilibrium turbulence phenomena down to the viscous sublayer. The calculated fluid flow and turbulence fields for the channel flows are in better agreement with the direct numerical simulation (DNS) results than those obtained using a Reynolds stress turbulence model, and the calculated near-wall dissipation rates are in qualitatively correct agreement with the DNS results. The LMS also successfully predicts the rapidly varying phase-lead of the wall shearing stress that occurs in a narrow range of the dimensionless frequency omega (+) = (omega x nu)/(upsilon x tau(exp2)) for the pulsating pipe flows while various other turbulence models fail to predict this phenomenon, and the LMS yields significantly improved numerical results for a wide range of the dimensionless frequency compared with those obtained using a rapid distortion theory (RDT). Kim, Sang-Wook Unspecified Center NCC3-229...