Simulation and validation of a spatially evolving turbulent boundary layer up to Reθ=8300Reθ=8300

• Large eddy simulation (LES) of zero-pressure gradient turbulent boundary layer at high Reynolds number (Re) is presented.
• LES is validated against high-fidelity direct numerical simulation (DNS) and experiments.
• Excellent agreement is found for integral quantities, statistics and spectra.
• Pressure statistics are evaluated and compared to existing experiments. 1D spectra show k-1 region as Re is increased.
• 1D and 2D velocity spectra show clear scale separation. Amplitude modulation between inner and outer layer is quantified.

Results of a finely resolved large-eddy simulation (LES) of a spatially developing zero-pressure-gradient turbulent boundary layer up to a Reynolds number of Reθ=8300Reθ=8300 are presented. The very long computational domain provides substantial assessment for suggested high Reynolds number (Re  ) trends. Statistics, integral quantities and spectral data are validated using high quality direct numerical simulation (DNS) ranging up to Reθ=4300Reθ=4300 and hot-wire measurements covering the remaining Re  -range. The mean velocity, turbulent fluctuations, skin friction, and shape factor show excellent agreement with the reference data. Through utilisation of filtered DNS, subtle differences between the LES and DNS could to a large extent be explained by the reduced spanwise resolution of the LES. Spectra and correlations for the streamwise velocity and the wall-shear stress evidence a clear scale-separation and a footprint of large outer scales on the near-wall small scales. While the inner peak decreases in importance and reduces to 4% of the total energy at the end of the domain, the energy of the outer peak scales in outer units. In the near-wall region a clear k-1k-1 region emerges. Consideration of the two-dimensional spectra in time and spanwise space reveals that an outer time scale λt≈10δ99/U∞λt≈10δ99/U∞, with the boundary layer thickness δ99δ99 and free-stream velocity U∞U∞, is the correct scale throughout the boundary layer rather than the transformed streamwise wavelength multiplied by a (scale independent) convection velocity. Maps for the covariance of small scale energy and large scale motions exhibit a stronger linear Re dependence for the amplitude of the off-diagonal peak compared to the diagonal one, thereby indicating that the strength of the amplitude modulation can only qualitatively be assessed through the diagonal peak. In addition, the magnitude of the wall-pressure fluctuations confirms mixed scaling, and pressure spectra at the highest Re give a first indication of a −7/3 wave number dependence.