Numerical and Experimental Unsteady Flow Analysis on Interflap Seals

Abstract

Interflap seals are often located between inner and outer flaps to maintain structural consistency and aerodynamic properties. This seals, often made of an elastomer material, have been observed to suffer from aeroelastic phenomena during the take-off and landing phases. In prior work, Dubois, R. established the baselines of the investigation, being this study focused on the characterization of low-subsonic flow around a three device airfoil system (slat, airfoil and flap) for a variable range of Reynolds numbers and angles of attack, with particular emphasis on the flap. The evolution of the aerodynamic coefficients and the Strouhal number at such conditions is determined by CFD computations and compared to wind tunnel measurements. The results reveal a remarkable dependence of the flow behavior to the Reynolds number, with shedding vortices observed under conditions similar to the ones encountered during landing and take-off. The Strouhal number of this fluctuations is observed to decrease with the angle of attack, with an increase in the amplitude of the fluctuations. The angle of attack has also a decreasing effect in the lift coefficient, while the opposite effect is observed in the drag coefficient, increasing with the mentioned angle.