Two-dimensional cross-spectrum of the streamwise velocity in turbulent boundary layers
Rahul Deshpande, Dileep Chandran, Jason P Monty, Ivan Marusic
Journal of Fluid Mechanics | Cambridge University Press (CUP) | Published : 2020
In this paper, we present the two-dimensional (2-D) energy cross-spectrum of the streamwise velocity (u) component and use it to test the notion of self-similarity in turbulent boundary layers. The primary focus is on the cross-spectrum (Φw cross) measured across the logarithmic (zo) and near-wall (zr) wall-normal locations, providing the energy distribution across the range of streamwise (λx) and spanwise (λy) wavelengths (or length scales) that are coherent across the wall-normal distance. Φw cross may thus be interpreted as a wall-filtered subset of the full 2-D u-spectrum (Φ), the latter providing information on all coexisting eddies at zo. To this end, datasets comprising synchronized t..View full abstract
The authors wish to acknowledge the Australian Research Council for financial support and thank the authors of Sillero et al. (2014) for making their DNS data available. The authors are also grateful to the anonymous reviewers for their helpful comments which improved the quality of the manuscript.