Numerical Analysis of Drag Reduction Effect in Turbulent Pipe Flow with Traveling Wavy Blowing and Suction

ORAL

Abstract

Skin friction drag greatly increases in turbulent flows compared with that in laminar flows. Therefore, reduction of the skin friction drag by flow control is of great significance to contribute to energy saving. It is well known that traveling wave control shows large drag reduction. In the present study, DNS of a turbulent pipe flow was performed in order to clarify mechanisms of drag reduction by traveling wave control. The traveling wave was implemented by blowing and suction at the wall and is expressed as the boundary condition of the wall-normal velocity. Pathlines were analyzed in order to investigate the flow field generated by the control. The analysis indicated that injected particles return toward the wall by the suction flow. Therefore, the flow is “closed” in the region near the wall. Drastic reduction of the random component of Reynolds shear stress in the closed flow suggests that there is no turbulence in the closed flow and it contributes to drag reduction.

–

Presenters

  • Shinya Koganezawa

    Department of Mechanical Systems Engineering, Tokyo University of Agriculture and Technology

Authors

  • Shinya Koganezawa

    Department of Mechanical Systems Engineering, Tokyo University of Agriculture and Technology

  • Akihiko Mitsuishi

    Department of Mechanical Systems Engineering, Tokyo University of Agriculture and Technology

  • Takaaki Shimura

    Department of Mechanical Systems Engineering, Tokyo University of Agriculture and Technology

  • Kaoru Iwamoto

    Department of Mechanical Systems Engineering, Tokyo University of Agriculture and Technology

  • Hiroya Mamori

    Department of Mechanical and Intelligent Systems Engineering, The university of Electro-Communications

  • Akira Murata

    Department of Mechanical Systems Engineering, Tokyo University of Agriculture and Technology