Numerical investigations of hydrodynamic performance of hydrofoils with leading-edge protuberances. (26th June 2015)

• Record Type: Journal Article
• Authors: Cai, Chang; Zuo, Zhigang; Liu, Shuhong; Wu, Yulin
• Is Part Of: Advances in mechanical engineering. Volume 7:Number 7(2015:Jul.)
• Publication Date: 2015-06-26
• Subjects: Hydrofoil -- stall -- leading-edge protuberance -- passive control -- computational fluid dynamics; Mechanical engineering -- Periodicals; 621.05
• DOI: 10.1177/1687814015592088
• Languages: English
• ISSNs: 1687-8132

Abstract

Leading-edge protuberances on airfoils or hydrofoils have been considered as a viable passive method for flow separation control recently. In this article, the hydrodynamic performance of a NACA 634 -021 (baseline) foil and two modified foils with leading-edge protuberances was numerically investigated using the Spalart–Allmaras turbulence model. It was found that modified foils performed worse than the baseline foil at pre-stall angles, while the lift coefficients at high angles of attack of the modified foils were increased. Both the deterioration of pre-stall and the improvement of post-stall performance were enhanced with larger amplitude of protuberance. Near-wall flow visualizations showed that the leading-edge protuberances worked in pairs at high angles of attack, producing different forms of streamwise vortices. An attached flow along some valley sections was observed, leading to a higher local lift coefficient at post-stall angles. The leading-edge protuberances were considered as sharing a similar mechanism as delta wings, increasing nonlinear lift at large angles of attack. The specific stall characteristics of this leading-edge modification could provide some guidelines for the design of some special hydrofoils or airfoils.