Shun He^1,*, Gaowei Cui²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.24, No.1, pp. 1-4, 2022, DOI:10.32604/icces.2022.08753

Abstract An investigation has been made into the nonlinear aeroelastic behavior of a supercritical airfoil (NLR 7301) considering free-play in transonic flow. Computational Fluid Dynamics (CFD) based on NavierStokes equations is implemented to calculate unsteady aerodynamic forces. A loosely coupled scheme with steady CFD and a graphic method are developed to obtain the static aeroelastic position. Frequency domain flutter solution with transonic aerodynamic influence coefficient is used to capture the linear flutter characteristic at different angle of attack (AoA). Time marching approach based on CFD is used to calculate the nonlinear aeroelastic response. The bifurcation diagram of pitching motion shows that… More >

Saima Akram^1,*, Allah Nawaz¹, Muhammad Bilal Riaz², Mariam Rehman³

Intelligent Automation & Soft Computing, Vol.31, No.3, pp. 1467-1482, 2022, DOI:10.32604/iasc.2022.019767

Abstract In this article, the maximum possible numbers of periodic solutions for the quartic differential equation are calculated. In this regard, for the first time in the literature, we developed new formulae to determine the maximum number of periodic solutions greater than eight for the quartic equation. To obtain the maximum number of periodic solutions, we used a systematic procedure of bifurcation analysis. We used computer algebra Maple 18 to solve lengthy calculations that appeared in the formulae of focal values as integrations. The newly developed formulae were applied to a variety of polynomials with algebraic and homogeneous trigonometric coefficients of… More >