Maosheng Wang, Yanyang Wang, Yihua Cao^*, Qiang Zhang

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.5, pp. 1301-1315, 2023, DOI:10.32604/fdmp.2023.023435 - 30 November 2022

Abstract The so-called coaxial compound helicopter features two rigid coaxial rotors, and possesses high-speed capabilities. Nevertheless, the small separation of the coaxial rotors causes severe aerodynamic interactions, which require careful analysis. In the present work, the aerodynamic interaction between the various helicopter components is investigated by means of a numerical method considering both hover and forward flight conditions. While a sliding mesh method is used to deal with the rotating coaxial rotors, the Reynolds-Averaged Navier-Stokes (RANS) equations are solved for the flow field. The Caradonna & Tung (CT) rotor and Harrington-2 coaxial rotor are considered to More >

Inamul Hasan^1,2,*, R. Mukesh², P. Radha Krishnan^1,2, R. Srinath¹, R. B. Dhanya Prakash²

Intelligent Automation & Soft Computing, Vol.33, No.1, pp. 567-584, 2022, DOI:10.32604/iasc.2022.023252 - 05 January 2022

Abstract In this research, the aerodynamic performance and flow characteristics of NASA SC (2)-0714 airfoil and HH02 airfoil in the helicopter main rotor are evidently analyzed. The supercritical airfoil is used in the aircraft for attaining better transonic and high-speed flow characteristics. Moreover, a specialized helicopter airfoil called HH02 is used in the Apache helicopter rotor for increasing the operational speed. As most of the high-speed helicopters are using four-bladed main rotor configuration, it is analyzed with prior attention. The lift and thrust act in different directions for the forward phase of the flight whereas the… More >

Guozhi Li¹, Yihua Cao^2,*

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.2, pp. 235-252, 2021, DOI:10.32604/fdmp.2021.014814 - 02 April 2021

Abstract The wake generated by the rotor of a helicopter can exert a strong interference effect on the fuselage and the horizontal/vertical tail. The occurrence of icing on the rotor can obviously make this interplay more complex. In the present study, numerical simulation is used to analyze the rotor wake in icing conditions. In order to validate the overall mathematical/numerical method, the results are compared with similar data relating to other tests; then, different simulations are conducted considering helicopter forward flight velocities of 0, 10, 20, 50, and 80 knots and various conditions in terms of More >

C. Mapelli¹, A. Manes^1,2, M. Giglio¹, D. Mombelli¹

Structural Durability & Health Monitoring, Vol.9, No.2, pp. 181-199, 2013, DOI:10.32604/sdhm.2013.009.181

Abstract The definition of a complex operative scenario like ballistic damage, that introduces large strains and failure, is a current challenge in the design of critical mechanical components. Aerospace, automotive and manufacturing industries have recently increased their interest in numerical simulations with the long term aim to make these approaches not only reliable enough to reproduce the experimental results but also to provide a trustworthy and effective tool for design. To achieve this aim, the knowledge and calibration of material behaviour is required. Starting from a previous characterization of the constitutive law and ductile failure criterion More >

Seawook Lee¹, Leesang Cho², Jin-Soo Cho³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.7, No.3, pp. 113-122, 2008, DOI:10.3970/icces.2008.007.113

Abstract Computational methods based on the solution of the flow model are widely used for the analysis of low-speed, inviscid, attached-flow problems. Most of such methods are based on the implementation of the internal Dirichlet boundary condition. In this paper, the time-domain panel method uses the piecewise constant source and doublet singularities. The present method utilizes the time-stepping loop to simulate the unsteady motion of the rotary wing blade for the KHP. The wake geometry is calculated as part of the solution with no special treatment. To validate the results of aerodynamic characteristics, the typical blade More >

Jyoti Ranjan Majhi, Ranjan Ganguli¹

CMES-Computer Modeling in Engineering & Sciences, Vol.27, No.1&2, pp. 25-36, 2008, DOI:10.3970/cmes.2008.027.025

Abstract The flapping equation for a rotating rigid helicopter blade is typically derived by considering 1) small flap angle, 2) small induced angle of attack and 3) linear aerodynamics. However, the use of nonlinear aerodynamics can make the assumptions of small angles suspect. A general equation describing helicopter blade flap dynamics for large flap angle and large induced inflow angle of attack is derived in this paper with nonlinear aerodynamics . Numerical simulations are performed by solving the nonlinear flapping ordinary differential equation for steady state conditions and the validity of the small angle approximations are More >

V.C. Santos¹, P.S. Lopes¹, R. Gärtner², A.B. Jorge¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.4, No.2, pp. 53-58, 2007, DOI:10.3970/icces.2007.004.053

Abstract This work presents an approach for weight and reliability optimization of aeronautical armors. Military and police helicopters are usually exposed to highly risky situations, with a high probability for these aircrafts to be hit by projectiles. In this context, floor aircraft armor can be used to protect the crews' lives. However, the armoring of an aircraft causes an increase in weight. If this extra weight is poorly arranged, the changes in aircraft centroid position may even destabilize the aircraft. Thus, it is essential to design an armor not only to protect the aircraft, but also… More >