Numerical investigation of aberrant aerodynamic behavior of wrap-around fins in collation with planar fins

Abstract

The anomalistic aerodynamic behavior of wrap around fins has kept the researchers engrossed in devising new design methods and analysis techniques. Rolling moment at zero incidence angle, induced forces and moments due to fin curvature, roll reversal phenomenon, static side moment and Magnus side moment are the main aggravations that make their aerodynamics more complex when compared with the planar fins. The present research effort provides a deep insight and explanation for this uncertain aerodynamics associated with wrap-around fins. At first, simulations of flow around isolated planar fin and curved fin has been performed to identify the effect of curvature. The results indicate a pressure loading for the curved fin at zero incidence angle, which was more confined towards the leading edge. Both curved and flat fins showed symmetric pressure distribution about mid chord on top and bottom surfaces. As a result, no side force was observed for isolated fins. Pressure loadings have distinct divisions for both the planar and curved fins that are similar in appearance to Mach lines. Subsequently, the effect of wall and the support hinges have been studied for wrap-around fins. Due to wall boundary the pressure distribution becomes asymmetric, which originates a side force. The presence of the support hinges creates shocks patterns at the bottom surface and generates unbalanced pressure loading. The predicted aerodynamic load for the wrap around fins is then used to perform static computational aeroelastic analysis to obtain true structural deformations. The results highlights the fact that the uneven structural displacements give rise to out of the plane forces that effects the aerodynamics and flight performance of systems with wrap around fins.

Numerical investigation of aerodynamic effects of opposite wrap-around fins at supersonic speeds

“…Their investigations demonstrated that the two fins differ in resulted rolling angles only, with other aerodynamic properties being mostly the same. Omar et al 12 further studied the aerodynamic behavior of displaced WAFs to that of flat fins. They illustrated that, at zero angle of attack, the pressure is different on either sides of the WAF, as compared to similar pressures on either sides of the flat fin.…”