WebbFor this purpose, various riblet geometries were tested experimentally. With an increasing misalignment to the flow direction the drag reduction ability of the riblets deteriorates. This effect is related to the geometry of the riblets, e.g., a riblet geometry with trapezoidal grooves and a tip angle of the ribs of α = 45° is less affected by ... WebbDrag reduction by riblets 1413 Riblet experiments have also been conducted in oil channels, which allow larger riblet dimensions and better control of the geometry, …
Model-based design of riblets for turbulent drag reduction
Webb12 maj 2015 · A Taylor–Couette facility was used to measure the drag reduction of a riblet surface on the inner cylinder. The drag on the surfaces of the inner and outer cylinders is determined from the measured torque when the cylinders are in exact counter-rotation. The three velocity components in the instantaneous flow field were obtained by tomographic … Webb13 apr. 2011 · The interaction of the overlying turbulent flow with riblets, and its impact on their drag reduction properties are analysed. In the so-called viscous regime of vanishing … kitchenaid coffee maker canada
Riblet drag reduction in mild adverse pressure gradients
Webb6 nov. 2024 · The fluid drag performance was evaluated using a rheometer. Results showed that the shark–skin-like surface with 90 degree orientation of scales exhibited the lowest viscosity drag. Its maximum viscosity reduction was 9%. A viscosity map was constructed based on the principals of fluid dynamic. WebbKeywords: Turbulence, drag reduction, riblets, boundary layers, skin friction . Introduction: In recent years, turbulent boundary layer drag reduction has become an important area of fluid dynamics research. Specifically, rising fuel costs greatly emphasized the usefulness and necessity of developing efficient viscous drag reduction methods. WebbThe skin of fast swimming sharks exhibits riblet structures aligned in the direction of flow which are known to reduce skin friction drag in the turbulent flow regime. Structures have been fabricated for study and application which replicate and improve upon the natural shape of the shark skin riblets, providing a maximum drag reduction of nearly 10%. mablethorpe motorhome parking