Drag-Reduction Effectiveness of Riblet Films in Adverse Pressure Gradients

ORAL

Abstract

Riblet films are micro-grooved structures that are widely known to passively reduce skin friction. Past studies have almost solely focused on riblet performance in channel-flows. However, possible applications of riblets include wind turbine blades, gas turbine blades, and other complex bodies that are exposed to non-zero pressure gradient flows---specifically adverse pressure gradients. We use high-resolution large eddy simulations of turbulent flow over three-dimensional riblets under an adverse pressure gradient. We analyze the computed results to quantify drag reduction effectiveness for different riblet shapes and to examine pertinent turbulent structures to gain a fundamental understanding of riblet performance.

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Authors

  • Aaron Boomsma

    University of Minnesota

  • Fotis Sotiropoulos

    University of Minnesota, St. Anthony Falls Laboratory, University of Minnesota, Minneapolis, USA, St. Anthony Falls Laboratory, University of Minnesota, St. Anthony Falls Lab., University of Minnesota, St. Anthony Falls Laboratory, Department of Civil Engineering, 2 Third Avenue SE, Minneapolis, MN 55414, USA, St. Anthony Falls Laboratory, College of Science and Engineering, Department of Civil Engineering, University of Minnesota, St. Anthony Falls Laboratory, Dept. of Civil Engineering, University of Minnesota, Saint Anthony Falls Laboratory, Civil Engineering, University of Minnesota