Please use this identifier to cite or link to this item: http://bura.brunel.ac.uk/handle/2438/31412
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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