SIMULATION OF A TURBULENT POLYMER SOLUTION FLOW OVER A FLAT PLATE

摘要

A non-Newtonian fluid Direct Numerical Simulation (DNS) tool is developed to predict the reduction of turbulent skin friction drag observed when the fluid is a dilute polymer solution. Results obtained with this tool are to be used to develop a Reynolds Averaged Navier Stokes (RANS) design tool that will allow the design of ship hulls and other external bodies that benefit in a predictable way from polymer-induced drag reduction. The FENE-P dumbbell model for viscoelastic fluids is used to provide the non-Newtonian stresses. The approach is tested with a turbulent flat-plate boundary layer case (Re_(δ~*) =1000). The inflow data is generated by a recycling method extended to include the polymer stresses. Results are presented for a coarse grid case in which the turbulence is not completely resolved and consist primarily of comparisons between Newtonian and polymer ocean turbulence characteristics, such as turbulence intensity and velocity profiles. Although the predicted drag is lower for the polymer solution case, it is not as significant as experimental observation. This discrepancy is attributed to the coarseness of the simulation.