Different from conventional streamwise-aligned riblets, converging and diverging (C–D) riblets are arranged obliquely along the main-flow direction, intending to induce a large-scale secondary flow that modulates or controls existing vortical structures in wall turbulence. In this study, we perform direct numerical simulations of turbulent over C–D at low Reynolds number investigate impacts on ...

Abstract In this paper, a model problem of viscous flow and heat transfer in rectangular converging (diverging) channel has been investigated. The governing equations are presented Cartesian Coordinates consequently they simplified solved with perturbation numerical methods. Initially, symmetrical solutions the boundary value found for upper half channel. Later on, these extended to lower then ...

We present results on modeling magnetic flux tubes in an unstably stratified medium and the flows around them using 2D axisymmetric magneto-hydrodynamic (MHD) simulations. The study is motivated by the formation of magnetic field concentrations at the solar surface in sunspots and magnetic pores and the large-scale flow patterns associated with them. The simulations provide consistent, self-mai...

A balanced force Refined Level Set Grid method for two-phase flows on structured and unstructured flow solver grids is presented. To accurately track the phase interface location, an auxiliary, high-resolution equidistant Cartesian grid is introduced. In conjunction with a dual-layer narrow band approach, this Refined Level Set Grid method allows for parallel, efficient grid convergence and err...