Effects of aspect ratio and orientation on the wake characteristics of low Reynolds number flow over a triangular prism

• Published in: Journal of fluids and structures 2014-04, Vol.46, p.59-76
• Main Authors: Ganga Prasath, S., Sudharsan, M., Vinodh Kumar, V., Diwakar, S.V., Sundararajan, T., Tiwari, Shaligram
• Format: Article
• Language: English
• Subjects: Aspect ratio; Critical Reynolds number; Fixed-grid simulation; Hydrodynamic forces; Triangular prism; Wake characteristics
• ISSN: 0889-9746; 1095-8622
• DOI: 10.1016/j.jfluidstructs.2013.12.008

The wake characteristics of unconfined flows over triangular prisms of different aspect ratios have been numerically analysed in the present work. For this purpose, a fixed Cartesian-grid based numerical technique that involves the porous medium approach to mimic the effect of solid blockage has been utilised. Correspondingly, laminar flow simulations ranging from the sub-critical regime (before the onset of vortex shedding) to the super-critical regime have been considered here within the limits of two-dimensionality. In the sub-critical regime, correlations relating the wake bubble length with Reynolds number (Re) have been proposed for various aspect ratios. Also, the effects of aspect ratio and Reynolds Number on the drag force coefficient (CD) have been characterised for two different geometrical orientations of the prism (base or apex facing the flow). Subsequently, the critical Reynolds number at the onset of vortex shedding has been predicted for each of the aspect ratio considered, by an extrapolation procedure. The unsteady flow characteristics of the super-critical regime are finally highlighted for different aspect ratios and triangular orientations considered in the study. •Laminar flows over triangular prisms are analysed by fixed grid porous body approach.•In the sub-critical regime, wake bubble length and Re have been linearly correlated.•The post-critical unsteady flow characteristics have also been highlighted.•Aspect ratio and orientation effects on the onset of vortex shedding are discussed.