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The virtual AirDyn: a simulation technique for evaluating the aerodynamic impact of ship superstructures on helicopter operations

Published online by Cambridge University Press:  27 January 2016

C. H. Kääriä ,
J. S. Forrest  and
I. Owen
C. H. Kääriä
Affiliation:
School of Engineering, University of Liverpool, Liverpool, UK
J. S. Forrest
Affiliation:
Prism Defence, Adelaide, Australia
I. Owen*
Affiliation:
School of Engineering, University of Lincoln, Lincoln, UK
*
iowen@lincoln.ac.uk
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Abstract

This paper describes a simulation technique that has been developed to quantify the unsteady forces and moments that are imposed onto a maritime helicopter by a ship’s airwake during a deck landing. An unsteady CFD-generated airwake, created using a CAD model of the ship, is integrated with a flight dynamics model of a helicopter. By holding the helicopter at a fixed position in the airwake it is possible to quantify the unsteady forces and moments imposed on the aircraft. The technique is therefore a software-based airwake dynamometer, and has been called the virtual AirDyn. As well as determining the mean loads, from consideration of the unsteady loads in the closed-loop pilot response frequency range of 0·2-2Hz it is also possible to quantify the magnitude of the unsteady disturbance in each axis. The loads are also indicators of the control activity the pilot would have to exert to maintain aircraft position and attitude. By placing the virtual AirDyn at different positions around the landing deck in different wind conditions, it is able to quantify the effect of the airwake on the mean and unsteady loads. The quantified loads can be explained by examining the CFD-generated flow field, and the geometric features on the ship’s superstructure that gave rise to them can be identified. The virtual AirDyn is therefore a tool that can be used to evaluate and inform ship design for maritime helicopter operations.

Type
Research Article
Information
The Aeronautical Journal , Volume 117 , Issue 1198 , December 2013 , pp. 1233 - 1248
Copyright
Copyright © Royal Aeronautical Society 2013 

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