A direct numerical simulation of a turbulent channel flow is performed.The unsteady Navier-Stokes equations are solved numerically at aReynolds number of 3300, based on the mean centerline velocity andchannel half-width, with about 4 million grid points. All essentialturbulence scales are resolved on the computational grid and no subgridmodel is used. A large number of turbulence statistics are computed andcompared with the existing experimental data at comparable Reynoldsnumbers. Agreements as well as discrepancies are discussed in detail.Particular attention is given to the behavior of turbulence correlationsnear the wall. A number of statistical correlations which arecomplementary to the existing experimental data are reported for thefirst time.