Skip to main content Accessibility help
×
Home

Turbulent flow over a flexible wall undergoing a streamwise travelling wave motion

  • LIAN SHEN (a1), XIANG ZHANG (a1), DICK K. P. YUE (a1) and MICHAEL S. TRIANTAFYLLOU (a1)

Abstract

Direct numerical simulation is used to study the turbulent flow over a smooth wavy wall undergoing transverse motion in the form of a streamwise travelling wave. The Reynolds number based on the mean velocity $U$ of the external flow and wall motion wavelength $\lambda$ is 10 170; the wave steepness is $2\pi a/\lambda=0.25$ where $a$ is the travelling wave amplitude. A key parameter for this problem is the ratio of the wall motion phase speed $c$ to $U$, and results are obtained for $c/U$ in the range of $-1.0$ to $2.0$ at $0.2$ intervals. For negative $c/U$, we find that flow separation is enhanced and a large drag force is produced. For positive $c/U$, the results show that as $c/U$ increases from zero, the separation bubble moves further upstream and away from the wall, and is reduced in strength. Above a threshold value of $c/U\approx 1$, separation is eliminated; and, relative to small- $c/U$ cases, turbulence intensity and turbulent shear stress are reduced significantly. The drag force decreases monotonically as $c/U$ increases while the power required for the transverse motion generally increases for large $c/U$; the net power input is found to reach a minimum at $c/U\approx 1.2$ (for fixed $U$). The results obtained in this study provide physical insight into the study of fish-like swimming mechanisms in terms of drag reduction and optimal propulsive efficiency.

Copyright

Corresponding author

Author to whom correspondence should be addressed: yue@mit.edu
MathJax
MathJax is a JavaScript display engine for mathematics. For more information see http://www.mathjax.org.

Turbulent flow over a flexible wall undergoing a streamwise travelling wave motion

  • LIAN SHEN (a1), XIANG ZHANG (a1), DICK K. P. YUE (a1) and MICHAEL S. TRIANTAFYLLOU (a1)

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed.