Numerical Investigation of Nature-Inspired Dune-Shaped Vortex Generators for Drag Reduction in a D-Shaped Cylinder Flow

Abstract Motivated by the geometric characteristics of barchan dunes, this study presents a numerical investigation of flow control strategies for a modified D-shaped cylinder equipped with nature-inspired barchan dune-shaped vortex generators (BDVGs). The research combines computational fluid dynamics (CFD) to systematically evaluate the aerodynamic performance enhancements achieved through this bio-inspired design. A comparative analysis of flow field characteristics between the baseline configuration and BDVGs-equipped configurations reveals significant improvements in flow management. The vortex generator design incorporates two critical geometric parameters: configuration and elevation amplitude. This investigation implements an improved delayed detached-eddy simulation (IDDES) approach to perform parametric optimization of BDVG dimensions at Reynolds number Re = 3.6 × 104. To ensure variable consistency and computational tractability, the optimized dimensional parameters were also retained for investigations at elevated Reynolds numbers. The underlying mechanisms of drag mitigation and aerodynamic oscillation suppression exerted by the BDVGs on D-shaped cylinder flows were comparatively analyzed under both Reynolds number regimes. Numerical results demonstrate substantial improvements in aerodynamic performance metrics. Compared to the baseline configuration, BDVGs-equipped cylinder achieves a maximum mean drag coefficient reduction of 32.3% and an 89.1% decrease in lift coefficient root-mean-square values. Detailed flow analysis reveals that the optimized BDVG geometry enhances flow characteristics through following primary mechanisms: downstream displacement of the pressure center, attenuation of large-scale vortex structures, and delay in vorticity dissipation.