Effect of aspect ratio variation on subsonic aerodynamics of cascade type grid fin at different gap-to-chord ratios. (3rd April 2020)

• Record Type: Journal Article
• Authors: Tripathi, M.; Sucheendran, M.M.; Misra, A.
• Is Part Of: Aeronautical journal. Volume 124:Number 1274(2020)
• Page Start: 472
• Page End: 498
• Publication Date: 2020-04-03
• Subjects: Grid fin, -- Cascade fins, -- Subsonic, -- Wind tunnel, -- Gap-to-chord ratio, -- Aspect ratio; Aeronautics -- Periodicals; 629.1305
• DOI: 10.1017/aer.2019.146
• Languages: English
• ISSNs: 0001-9240

Abstract

ABSTRACT: This paper dwells upon investigating the effect of aspect ratio ( AR ) variation on the aerodynamic performance of unconventional control surfaces called grid fins by virtue of a series of subsonic experiments on a simplified grid fin variant called the cascade fin. Wind tunnel tests were performed for different AR (variable span) grid fins. The same had been investigated for different gap-to-chord ratio ( g / c ) variants. Results demonstrated a tangible increase in the aerodynamic efficiency as well as stall angle reduction for higher AR . Moreover, higher AR leads to increased pitching moment, which emphasizes elevated hinge moment requirements. The study ensued the presence of higher deviation between the low AR fins, that is $AR<2$ compared to the pertinent deviations between the high AR fins, that is $AR\geq2$ . The effect associated with these variations was termed as span effect in this paper. It was established that, the deviations arising due to this phenomena were lesser for higher g / c and higher AR . The analysis of AR variation for different g / c presented a limiting value of AR reduction for stall performance enhancement. Thus, optimised selection of the g / c and AR values can lead to enhanced aerodynamic efficiency alongside an improved stalling characteristic.