Aerodynamic performance improvement of WIG aircraft

Abstract

Purpose This paper aims to investigate the aerodynamic characteristics as well as static stability of wing-in-ground effect aircraft. The effect of geometrical characteristics, namely, twist angle, dihedral angle, sweep angle and taper ratio are examined. Design/methodology/approach A three-dimensional computational fluid dynamic code is developed to investigate the aerodynamic characteristics of the effect. The turbulent model is utilized for characterization of flow over wing surface. Findings The numerical results show that the maximum change of the drag coefficient depends on the angle of attack, twist angle and ground clearance, in a decreasing order. Also, it is found that the lift coefficient increases as the ground clearance, twist angle and dihedral angle decrease. On the other hand, the sweep angle does not have a significant effect on the lift coefficient for the considered wing section and Reynolds number. Also, as the aerodynamic characteristics increase, the taper ratio befits in trailing state. Practical implications To design an aircraft, the effect of each design parameter needs to be estimated. For this purpose, the sensitivity analysis is used. In this paper, the influence of all parameter against each other including ground clearance, angle of attack, twist angle, dihedral angle and sweep angle for the NACA 6409 are investigated. Originality/value As a summary, the contribution of this paper is to predict the aerodynamic performance for the cruise condition. In this study, the sensitivity of the design parameter on aerodynamic performance can be estimated and the effect of geometrical characteristics has been investigated in detail. Also, the best lift to drag coefficient for the NACA 6409 wing section specifies and two types of taper ratios in ground effect are compared.

Numerical study of boundary layer transition using intermittency model

“…According to the numerical studies by Tahani et al (2017a), k-v SST produces the lowest error rate of lift and drag compared with measurements for flow over an airfoil in ground effect. In another work, Tahani et al (2017b) assessed different turbulence models including k-v SST, SAS and DDES over a pitching NACA-0012 airfoil in a transonic regime to investigate the accuracy of these models to predict shock-buffet and separation of boundary layer and concluded that DDES can produce better results than the other models in such flows compared with experiment.…”

Aerodynamic ground effects on DLRF6 vehicle

“…Owing to the Mach number of 0.75, computation predicts the shock location and strength. All the simulation results simulate the pressure distribution on the lower surface perfectly well (Tahani et al , 2017a, 2017b, 2017c). The results from all number of meshes predict the shock locations quite well, with a little difference in the shock strength.…”

“…Owing to the Mach number of 0.75, computation predicts the shock location and strength. All the simulation results simulate the pressure distribution on the lower surface perfectly well (Tahani et al, 2017a(Tahani et al, , 2017b, The numerical dataset for validation of this study is based on a series of articles (Brodersen et al, 2002;Laflin et al, 2005;Vassberg et al, 2007), experimental findings of ONERA wind tunnel lab (Rossow et al, 1994) (Figure 6) and a recent article on configuration of DLRF6 in ground effect (Deng et al, 2017).…”

“…The numerical simulation is conducted by solving the equations for conservation of mass, momentum and energy simultaneously (Tahani et al , 2012; 2017a, 2017b, 2017c; Djavareshkian et al , 2011). The transport equations for k and ε are expressed as equations (1) and (2): …”

“…Tahani et al (2017a, 2017b, 2017c) considered the wing as one of the main components of the vehicle. The stability sensitivity and generated lift and drag owing to geometric specifications of a wing including the angle of twist, dihedral angle, sweep angle and taper ratio were studied.…”