Direct Numerical Simulations of Turbulent Flow Over Various Riblet Shapes in Minimal-Span Channels
S Endrikat, D Modesti, M MacDonald, R Garcia-Mayoral, N Hutchins, D Chung
Flow, Turbulence and Combustion | Springer Verlag | Published : 2020
Riblets reduce skin-friction drag until their viscous-scaled size becomes large enough for turbulence to approach the wall, leading to the breakdown of drag-reduction. In order to investigate inertial-flow mechanisms that are responsible for the breakdown, we employ the minimal-span channel concept for cost-efficient direct numerical simulation (DNS) of rough-wall flows (MacDonald et al., J. Fluid Mech., vol. 816, 2017, pp. 5–42). This allows us to investigate six different riblet shapes and various viscous-scaled sizes for a total of 21 configurations. We verify that the small numerical domains capture all relevant physics by varying the box size and by comparing to reference data from full..View full abstract
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Awarded by Australian Research Council
This project was supported by the Australian Research Council Discovery Project DP170102595. D. Modesti was partially funded through the "EZ Founder's Scholarship".