Direct numerical simulation of a turbulent boundary layer up to Re-theta=2500

Direct numerical simulations (DNSs) of a turbulent boundary layer (TBL) with Re??=570-2560 were performed to investigate the spatial development of its turbulence characteristics. The inflow simulation was conducted in the range Re??=570-1600 by using Lund's method. To resolve the numerical periodicity induced by the recycling method, we adopted a sufficiently long streamwise domain of x/??in,i=1000 (=125??0,i), where ??in,i is the inlet momentum thickness and ??0,i is the inlet boundary layer thickness in the inflow simulation. Furthermore, the main simulation with a length greater than 50??0 was carried out independently by using the inflow data, where ??0 is the inlet boundary layer thickness of the main simulation. The integral quantities and the first-, second- and higher-order turbulence statistics were compared with those of previous data, and good agreement was found. The present study provides a useful database for the turbulence statistics of TBLs. In addition, instantaneous field and two-point correlation of the streamwise velocity fluctuations displayed the existence of the very large-scale motions (VLSMs) with the characteristic widths of 0.1-0.2?? and that the flow structure for a length of approximately ???6?? fully occupies the streamwise domain statistically.close1