On the interaction of a compliant wall with a turbulent boundary layer

Abstract

Abstract

Experiments and Modeling of a Compliant Wall Response to a Turbulent Boundary Layer with Dynamic Roughness Forcing

“…Some deviation can be seen very near the wall, particularly in the u rms . In addition, while v rms very close to the rigid wall appears to exceed that for the compliant wall in apparent contrast to the findings of [5], this could be attributed to the differences in the parameters. More specifically, the study of Wang et al [5], which identified a significant increase in v rms near the wall, had similar levels of wall deformation in viscous scale while having significantly higher Re τ than our study.…”

“…In addition, while v rms very close to the rigid wall appears to exceed that for the compliant wall in apparent contrast to the findings of [5], this could be attributed to the differences in the parameters. More specifically, the study of Wang et al [5], which identified a significant increase in v rms near the wall, had similar levels of wall deformation in viscous scale while having significantly higher Re τ than our study. The study of Rosti and Brandt [8], at lower Re τ , showed no significant changes in the Reynolds stress tensor for the studied case with smallest wall deformation, which is still an order of magnitude larger in viscous scales compared with the measured wall deformation presented here.…”

“…The experimental measurements showed minimal difference in mean profile and flow statistics between the RW-DRF and CW-DRF cases and suggested a one-way coupling between the fluid and surface in the classical sense, or at least only mild changes relative to the rigid wall turbulence structure [5]. This may be the result of the low Reynolds number, therefore low inertia flow not causing enough surface deformation to create significant changes in the flow statistics.…”

“…Together, these simplifications significantly reduced the costs for the resolvent computation while still capturing the most significant aspects of the structure of the modes. The comparison between the experimental and model responses of the flow to the synthetic excitation by dynamic roughness for the RW and CW cases demonstrate that resolvent analysis is capable of identifying the type of near-wall changes that may underlie the observations of changes to turbulence structure for even sub-viscous-scale wall deformations [5,8,9], a topic for future work.…”

“…In a similar experiment, Choi et al [4] reported drag reduction on a slender body of revolution as high as 7%. Wang et al [5] studied the wall deformation and flow response over a compliant wall for a range of material properties and identified the associated changes to the mean velocity and turbulence profiles. Tempering some of the optimistic experimental findings are more recent Direct Numerical Simulation (DNS) studies.…”