Direct Numerical Simulation of Turbulent Flow in a Square Pipe

A numerical analysis is conducted without introducing any turbulence model for the turbulent flow in a square pipe. The direct numerical calculation approach generally requires a huge computational time and memory size, and is possibly performed on a relatively coarse grid system. Therefore, evaluation of the solution for the coarse grid system is important in practical applications. Comparison with the experiment and the large eddy simulation (LES) reveals that the present calculation successfully predicts the characteristic feature of the turbulent flow even with the coarse grid system. Quantitative improvement of the solution is achieved nearly in proportion to the grid resolution squared.