Modelling the helicopter rotor aerodynamics at forward flight with free wake model and URANS method

    Yuri Ignatkin Affiliation
    ; Pavel Makeev   Affiliation
    ; Sergey Konstantinov   Affiliation
    ; Alexander Shomov   Affiliation


The presented work is dedicated to the numerical study of the aerodynamic characteristics of the helicopter rotor. Two approaches to modeling of the rotor are applied: the free wake model developed by the Authors with using steady airfoil characteristics and the Unsteady RANS method based on the Ansys Fluent software. The modes of hovering and horizontal flight in the range of advancing ratio μ = (0-0.45) are considered. The shapes of the rotor wake, the distributions of the normal force coefficient and the fields of inductive velocities for all considered flight modes are calculated. For a particular case with μ = 0.25 there is a comparison with experimental data. The time needed for calculation of the applied methods is estimated. Accuracy of the used methods in the framework of the solved task is analysed with taking into account used models assumptions. It is shown that in the range of μ = (0-0.25) the free wake model provides a fast and reliable calculation of the aerodynamic characteristics of the helicopter rotor. For values of μ > 0.35 it is necessary to take into account the unsteady characteristics of the airfoil.

Keyword : helicopter rotor, free wake model, URANS method, forward flight, aerodynamic characteristics

How to Cite
Ignatkin, Y., Makeev, P., Konstantinov, S. and Shomov, A. 2020. Modelling the helicopter rotor aerodynamics at forward flight with free wake model and URANS method. Aviation. 24, 4 (Nov. 2020), 149-156. DOI:
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Nov 9, 2020
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Alvarez, E. J., & Ning, A. (2018). Development of a vortex particle code for the modeling of wake interaction in distributed propulsion. Proceedings of AIAA Applied Aerodynamics Conference (p. 22). Atlanta, USA.

Belotserkovskii, S. M., & Loktev, B. E. (1992). Computer-aided study of aerodynamic and aeroelastic characteristics of the helicopter rotors. Mashinostroenie.

Bhagwat, M. J., & Leishman, J. G. (2000). Time-accurate modeling of rotor wakes using a free-vortex wake method. Proceedings of 18th AIAA Applied Aerodynamics Conference (pp. 236–246). Denver, USA.

Bhagwat, M., Moulton, M. A., & Caradonna, F. X. (2006). Hybrid CFD for rotor hover performance prediction. Proceedings of 24th Applied Aerodynamics Conference. San Francisco, USA.

Colmenares, J. D., Lopez, O. D., & Preidikman, S. (2015). Computational study of a transverse rotor aircraft in hover using the unsteady vortex lattice method. Mathematical Problems in Engineering, 1, 1–9.

Dehaeze, F., Barakos, G. N., Kusyumov, A. N., Kusyumov, S. A., & Mikhailov, S. A. (2018). Exploring the detached-eddy simulation for main rotor flows. Russian Aeronautics, 61(1), 37–44.

Deng, J., Fan, F., Liu, P., Huang, S., & Lin, Y. (2019). Aerodynamic characteristics of rigid coaxial rotor by wind tunnel test and numerical calculation. Chinese Journal of Aeronaut, 32(3), 568–576.

Dindar, M., Shephard, M. S., Flaherty, J. E., & Jansen, K. (2000). Adaptive CFD analysis for rotorcraft aerodynamics. Computer Methods in Applied Mechanics and Engineering, 189, 1055–1076.

Dominique, F., Lone, M., Weber, S., & Sharma, A. (2018). Fast computational aeroelastic analysis of helicopter rotor blades. Proceedings of AIAA Aerospace Sciences Meeting, 1–23.

Farrokhfal, H., & Pishevar, A. R. (2014). A new coupled free Wake-CFD method for calculation of helicopter rotor flow-field in hover. Journal of Aerospace Technology and Management, 6(2), 129–147.

Garipova, L. I., Batrakov, A. S., Kusyumov, A. N., Mikhailov, S. A., & Barakos, G. N. (2015). Estimates of hover aerodynamics performance of rotor model. Russian Aeronautics, 57(3), 223–231.

He, C., & Rajmohan, N. (2016). Modeling the aerodynamic interaction of multiple rotor vehicles and compound rotorcraft with viscous vortex particle method. Proceedings of AHS 72nd Annual Forum, 18.

He, C., & Zhao, J. (2009). Modeling rotor wake dynamics with viscous vortex particle method. AIAA Journal, 47(4), 902–915.

Homayoun, E., & Amir, N. (2003). Application of vortex lattice and quasi-vortex lattice method with free wake in calculation of aerodynamic characteristics of a hovering helicopter rotor blade in ground effect. Scientia Iranica, 10(1), 84–90.

Ignatkin, Y. M., & Konstantinov, S. G. (2012). Researches of aerodynamic characteristics of a main rotor helicopter using CFD method. Trudy MAI, 57, 1–22.

Ignatkin, Y. M., Makeev, P. V., Grevtsov, B. S., & Shomov, A. I. (2009). A nonlinear blade vortex propeller theory and its applications to estimate aerodynamic characteristics for helicopter main rotor and anti-torque rotor. Vestnik MAI, 16(5), 24–31.

Johnson, W. (2013). Rotorcraft aeromechanics. Cambridge university press.

Kelly, R., Jemcov, A., Rennie, M., Jumper, E. J., Whiteley, M., & Goorskey, D. (2015). Computation of the aero-optical effect of a helicopter rotor wake using unsteady RANS and LES. Proceedings of 53rd AIAA Aerospace Sciences Meeting, 15.

Kinzel, M. P., Cornelius, J. K., Schmitz, S., Palacios, J., Langelaan, J. W., Adams, D. S., & Lorenz, R. D. (2019). An investigation of the behavior of a coaxial rotor in descent and ground effect. In AIAA Scitech 2019 Forum.

Kritsky, B. S., Mahnyov, M. S., Mirgazov, R. M., Subbotina, P. N., & Trebunskih, T. V. (2016). Aerodynamic characteristics calculation of single rotor blade using FLOWFD, ANSYS FLUENT and RC-VTOL. Civil Aviation High Technologies, 223, 77–83.

Leishman, J. G. (2006). Principles of helicopter aerodynamics. Cambridge university press.

Long, L., & Fritz, T. E. (2004). Object-oriented unsteady vortex lattice method for flapping flight. Journal of Aircraft, 41(6), 1275–1290.

Potsdam, M., Smith, M., & Renaud, T. (2009). Unsteady computations of rotor-fuselage interaction. Proceedings of the 35th European Rotorcraft Forum, 23.

Shcheglova, V. M. (2011). Aerodynamic calculation method of the main rotor taking into account diffusion of free vortices for small flight speeds. TsAGI Science Journal, 42, 179–203.

Shi, Y., Xu, Y., Xu, G., & Wei, P. (2017). A coupling VWM/CFD/CSD method for rotor airload prediction. Chinese Journal of Aeronautics, 30, 204–215.

Singh, P., & Friedmann, P. (2017). Application of vortex methods to coaxial rotor wake and load calculations in hover. Journal of Aircraft, 55, 1–9.

Tan, J., Sun, Y., & Barakos, G. (2018). Unsteady loads for coaxial rotors in forward flight computed using a vortex particle method. The Aeronautical Journal, 122, 1–22.

Wenping, S., Zhong-Hua, H., & Qiao Zhi, D. (2007). Prediction of hovering rotor noise based on reynolds-averaged navier–stokes simulation. Journal of Aircraft, 44, 1391–1395.

Zhao, Y., Shi, Y., & Xu, G. (2017). Helicopter blade-vortex interaction airload and noise prediction using coupling CFD/VWM method. Applied Sciences, 7(4), 381.