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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2016, Vol. 37 ›› Issue (3): 771-779.doi: 10.7527/S1000-6893.2015.0253

• Fluid Mechanics and Flight Mechanics • Previous Articles     Next Articles

Numerical simulation of a helicopter operating in a reconstructed ship airwake based on POD method

JI Honglei, CHEN Renliang, LI Pan   

  1. National Laboratory of Science and Technology on Rotorcraft Aeromechanics, College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
  • Received:2015-03-31 Revised:2015-09-14 Online:2016-03-15 Published:2015-09-23
  • Supported by:

    National Natural Science Foundation of China(51405227);The Fundamental Research Funds for the Central Universities(NS2014011)

Abstract:

The proper orthogonal decomposition(POD) method is used to reduce the large amount of ship airwake data and a simulation method of a helicopter operating in a reconstructed ship airwake based on the POD method is developed. Firstly, a commercial computational fluid dynamics(CFD) software is used to calculate and sample the unsteady ship airwake. Secondly, the POD mode functions of the sample data are extracted, and a small number of the mode functions can well capture the main characteristics of the original fluid field and are used to reconstruct the ship airwake. Finally, a higher-order helicopter flight dynamic model coupled with the reconstructed ship airwake is established. An example of a helicopter recovery task in an unsteady ship airwake is simulated, and the time histories of control stick inputs and helicopter states are compared with the flight test results. The results show that the reconstructed ship airwake data with the POD method is about 8.5% of the original sample data and the reconstructed fluid field agrees well with the original fluid field, so the POD method is useful for reducing the ship airwake data. The comparison between the simulation results and flight test data indicates that the impact of the unsteady ship airwake on helicopter is captured, therefore the simulation method is suitable for the research of a helicopter operating in an unsteady ship airwake.

Key words: helicopter, unsteady, ship airwake, proper orthogonal decomposition, flight dynamics

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