Trimming analysis of flexible aircrafts based on computational fluid dynamics/computational structural dynamics coupling methodology

Abstract

A numerical methodology based on the coupling of computational fluid dynamics (CFD) and computational structural dynamics is established to obtain the trimming characteristics of flexible aircrafts in this paper. Reynolds-averaged Navier–Stokes equations are solved through CFD technique. Based on the frame of unstructured mesh, techniques of dynamic chimera mesh and morphing mesh are adopted to treat the data transfer between different computational zones and structure deformation caused by aeroelasticity, respectively. When it is applied to a projectile model with large slenderness ratio constructed in this paper, convergence histories of various initial conditions demonstrate the efficiency and robustness of the algorithm. The influence of the structural rigidity and normal loads on the trimming condition of flexible projectiles is investigated, and the locations of the aerodynamic center with various rigidities present the explanation that elastic deformation can move the aerodynamic center forward and weaken the margin of the stability. Furthermore, the trimming condition of flexible projectiles with propulsion is researched, which indicates that thrust misalignment will increase the effect of elastic deformation on the trimming condition, and the stability margin will be further weakened because of thrust misalignment. The conclusion provided in this paper can provide guidance for the structural design, control system design, and stability analysis for modern aircrafts with small stability margin and low rigidity.

Keywords

Flexible aircrafts computational fluid dynamics/computational structural dynamics coupling trimming analysis elastic deformation stability margin

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References

Vepa

. Flight dynamics, simulation, and control: for rigid and flexible aircraft, Boca Raton, FL: CRC Press, 2014.

Sotoudeh

Hodges

Seok

. Validation studies for aeroelastic trim and stability analysis of highly flexible aircraft. J Aircr 2010; 44: 1528–1545.

Van Schoor

Von Flotow

. Aeroelastic characteristics of a highly flexible aircraft. J Aircr 1990; 27: 901–908.

Wright

Cooper

. Introduction to aircraft aeroelasticity and loads: second edition, Hoboken, NJ: Wiley, 2015.

Oliveira E, Gasbarriy P and Fonseca IM. Flight dynamics numerical computation of a sounding rocket including elastic deformation model. AIAA2015-2710, 2015.

Rui

Abbas

. Elastic dynamic effects on the trajectory of a flexible launch vehicle. J Spacecr Rockets 2015; 52: 1586–1602.

Rodden WP and Johnson EH. MSC/NASTRAN Version 68 Aeroelastic Analysis Users Guide. New York: The MacNeal-Schwendler Corporation, 1994.

Patil MJ. Nonlinear aeroelastic analysis of joined-wing aircraft. AIAA 2003-1487, 2003.

Zhang

Xiang

. Static and dynamic characteristics of coupled nonlinear aeroelasticity and flight dynamics of flexible aircraft. Acta Aeronaut Astronaut Sin 2011; 32: 1569–1582.

10.

Xie

Wang

Yang

, et al.Static aeroelastic analysis of very flexible wing based on the non-planar vortex lattice method. Chin J Aeronaut 2013; 26: 514–521.

11.

Liu

Xie

Wang

, et al.Nonplanar aerodynamic computation and trim analysis under large deflection of flexible aircraft. Eng Mech 2015; 32: 239–249.

12.

Palacios R and Cesnik C. Static nonlinear aeroelasticity of flexible slender wings in compressible flow. AIAA 2005-1945, 2005.

13.

Guo

Liu

. Numerical determination of trim angle of attack for reentry vehicles using dynamic unstructured grids. ACTA Aerodyn Sin 2004; 22: 255–258.

14.

Ritter M. Nonlinear Numerical Flight Dynamics of Flexible Aircraft in the Time Domain by Coupling of CFD, Flight Mechanics, and Structural Mechanics. In: Dillmann A. et al (eds) New Results in Numerical and Experimental Fluid Mechanics VIII, Notes on Numerical Fluid Mechanics and Multidisciplinary Design 2013; 121: 339–347. Springer-Verlag.

15.

Bagherzadeh

. Flight dynamics modeling of elastic aircraft using signal decomposition methods. Proc IMechE, Part G: J Aerospace Engineering 2019; 233: 4380–4395.

16.

Zhang

, et al.Effects of aeroelasticity on the performance of hypersonic inlet. Proc IMechE, Part G: J Aerospace Engineering 2018; 232: 2108–2121.

17.

Meng

. Effects of structural thermal boundary conditions on hypersonic aerothermoelasticity of all-movable control surface. Proc IMechE, Part G: J Aerospace Engineering 2019; 233: 2673–2689.

18.

Zhang

. GA-SQP algorithm for solving equilibrium states of hypersonic vehicles. Acta Aeronaut Astronaut Sin 2012; 33: 138–146.

19.

Hua

. Effect of elastic deformation on the trajectory of aerial separation. Aerosp Sci Technol 2015; 45: 128–139.

20.

Hua

Lei

, et al.Effect of elastic deformation on flight dynamics of projectiles with large slenderness ratio. Aerosp Sci Technol 2017; 71: 347–359.

21.

Neumann J and Ritter M. Steady and unsteady aeroelastic simulations of the HIRENASD and wind tunnel experiment. IFASD 2009-132, 2009.

22.

Lijewski

Suhs

. Time-accurate computational fluid dynamics approach to transonic store separation trajectory prediction. J Aircr 1994; 31: 886–891.