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arXiv · 1908.09565

Drag Reduction and Energy Saving by Spanwise Traveling Transversal Surface Waves for Flat Plate Flow

Marian Albers·Pascal S. Meysonnat·Daniel Fernex·Richard Semaan·Bernd R. Noack·Wolfgang Schröder
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Abstract

Wall-resolved large-eddy simulations are performed to study the impact of spanwise traveling transversal surface waves in zero-pressure gradient turbulent boundary layer flow. Eighty variations of wavelength, period, and amplitude of the space- and time-dependent sinusoidal wall motion are considered for a boundary layer at a momentum thickness based Reynolds number of $Re_\theta = 1000$. The results show a strong decrease of friction drag of up to $26\,\%$ and considerable net power saving of up to $10\,\%$. However, the highest net power saving does not occur at the maximum drag reduction. The drag reduction is modeled as a function of the actuation parameters by support vector regression using the LES data. A substantial attenuation of the near-wall turbulence intensity and especially a weakening of the near-wall velocity streaks are observed. Similarities between the current actuation technique and the method of a spanwise oscillating wall without any normal surface deflection are reported. In particular, the generation of a directional spanwise oscillating Stokes layer is found to be related to skin-friction reduction.

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Marian Albers, Pascal S. Meysonnat, Daniel Fernex, Richard Semaan, Bernd R. Noack, Wolfgang Schröder. 2019-08-26. Drag Reduction and Energy Saving by Spanwise Traveling Transversal Surface Waves for Flat Plate Flow. https://arxiv.org/abs/1908.09565

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