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Title: | Modelling visibility in particle-fluid flow fields generated by helicopter rotors |
Authors: | Langdon, S Needham, D |
Issue Date: | 16-Jul-2025 |
Publisher: | American Institute of Aeronautics and Astronautics (AIAA) |
Citation: | Langdon, S. and Needham, D. (2025) 'Modelling visibility in particle-fluid flow fields generated by helicopter rotors', AIAA Aviation Forum, Las Vegas, NE, USA, 21-25 July. AIAA 2025-3824, pp. 1 - 16. doi: 10.2514/6.2025-3824. |
Abstract: | As a helicopter descends towards a bed of sand, a high velocity particle laden cloud can form around the helicopter body, a phenomenon known as “brownout”, and a consequence of which can potentially be a significant deterioration in visibility for the helicopter pilot. Here we consider a recently developed physically based rational mathematical model for the generation of wind-driven particle flow fields from otherwise static particle beds, one application of which is the scenario considered here. We introduce a directional opacity measure, defined for each observation angle from the helicopter cockpit, and show how visibility may vary in the model as certain parameters are varied. In particular, we demonstrate a counterintuitive result suggesting that, with specific yet potentially realistic parameter choices, pilot visibility may be improved in some viewing directions if the helicopter were hovering at a lower altitude. |
Description: | Paper presented at the AIAA Aviation Forum and Ascend, Las Vegas, NE, USA, 21-25 July, Session: Multiphase Flows I. |
URI: | https://bura.brunel.ac.uk/handle/2438/31412 |
DOI: | https://doi.org/10.2514/6.2025-3824 |
ISBN: | 978-1-62410-738-2 (ebk) |
Other Identifiers: | ORCiD: Stephen Langdon https://orcid.org/0000-0002-0572-5137 |
Appears in Collections: | Dept of Mathematics Research Papers |
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FullText.pdf | This is the accepted manuscript version of an article which has been published in final form on AIAA Electronic Library at https://doi.org/10.2514/6.2025-3824, Copyright © 2025 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. All requests for copying and permission to reprint should be submitted to CCC at https://www.copyright.com; employ the eISSN 1533-385X to initiate your request. See also AIAA Rights and Permissions https://www.aiaa.org/randp. | 909.48 kB | Adobe PDF | View/Open |
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