2026-05-12 東北大学
図1. 東北大学流体科学研究所の1m磁力支持天秤装置（1m-MSBS）で浮揚された流線型模型
＜関連情報＞
- https://www.tohoku.ac.jp/japanese/2026/05/press20260512-02-DMR.html
- https://www.cambridge.org/core/journals/journal-of-fluid-mechanics/article/dmr-effect-on-drag-reduction-of-a-streamlined-body-measured-by-magnetic-suspension-and-balance-system/0E3FF950CCC66DEFCBA3D3DCD36CE2B6
磁気浮上式バランスシステムで測定した、流線型物体の抗力低減に対するDMR効果 DMR effect on drag reduction of a streamlined body measured by magnetic suspension and balance system
Aiko Yakeno[,Hiroyuki Okuizumi,Kento Inokuma and Yoshiyuki Watanabe
Journal of Fluid Mechanics Published:07 May 2026
DOI:https://doi.org/10.1017/jfm.2026.11520
Abstract
This study experimentally investigates the aerodynamic drag reduction capabilities of distributed micro-roughness (DMR) coatings on a streamlined model, utilising the 1-m magnetic suspension and balance system (MSBS) at Tohoku University. Previous direct numerical simulations indicated that DMR can mitigate turbulent-energy growth by suppressing Tollmien–Schlichting waves and influencing the breakdown of streamwise vortices. The present work provides the first experimental validation of these effects using an interference-free MSBS, which is essential for accurate measurement in the laminar and transitional regimes. A streamlined model was tested with two rows of artificial tripping tape to induce transition; the DMR height was approximately 1 % of the local boundary layer thickness, significantly smaller than typical roughness elements. Direct aerodynamic drag measurements using the MSBS revealed a substantial reduction of up to 43.6 % within the transitional flow regime. Crucially, integrated analysis using wall-resolved large eddy simulations (LES) and dynamic oil-flow visualisation confirmed that this benefit does not mainly originate from the suppression of flow separation. The LES drag decomposition established that the total pressure-drag budget is subordinate to skin friction, a finding complemented by oil-flow observations, which revealed qualitatively similar flow patterns regardless of the surface condition. Consequently, the observed drag reduction is primarily ascribed to friction drag reduction achieved through the modification of the boundary layer state. These findings provide compelling experimental evidence for the efficacy of DMR and offer valuable insights for optimising surface designs for passive flow control.
