Turbulence without Tears : Residual-Based VMS , Weak Boundary Conditions , and Isogeometric Analysis of Wall-Bounded Flows

In this work, we combine i) NURBS-based isogeometric analysis, ii) residual-driven turbulence modeling and iii) weak imposition of Dirichlet boundary conditions on uniform, unstretched meshes to compute wall-bounded turbulent flows. While the first two ingredients were shown to be successful for turbulence computations at medium Reynolds number [1, 5], it is the weak imposition of no-slip boundary conditions on coarse uniform meshes that maintains the good performance of the proposed methodology at higher Reynolds number [7, 8]. These three ingredients form a basis of a possible practical strategy for computing engineering flows, somewhere between RANS and LES in complexity. We demonstrate this by solving two challenging incompressible turbulent benchmark problems: channel flow at friction-velocity based Reynolds number 2003 and flow in a planar asymmetric diffuser. We observe good agreement between our calculations of mean flow quantities and both reference computations and experimental data. This lends some credence to the proposed methodology, which we believe may become a viable engineering tool.