Direct numerical simulation of turbulent channel flow of polymer solution

The drag reduction characteristic of polymer turbulence in channel flows was investigated using the direct numerical simulation (DNS). In the simulations, the spectral methods employing Fourier series and Chebyshev polynomial were used to make the spatial discretization and the time-splitting method with second-order time accuracy was adopted to carry out time advancement. For three-dimension turbulent channel flows of a polymer solution, based on the FENE-P model, the obtained efficiency of drag reduction for the four cases show that there exists the "onset" phenomena. Based on the O-B model, the simulations show that in low drag reduction, the effect of polymer on turbulence mainly occurs in the near wall region, and in high drag reduction, the effect of polymer on turbulence occurs in the whole flowfield.