Accession Number:

ADA509010

Title:

Rotorcraft Downwash Flow Field Study to Understand the Aerodynamics of Helicopter Brownout

Descriptive Note:

Conference paper

Corporate Author:

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION MOFFETT FIELD CA AMES RESEARCH CENTER

Report Date:

2008-10-01

Pagination or Media Count:

28.0

Abstract:

Rotorcraft brownout is caused by the entrainment of dust and sand particles in helicopter downwash, resulting in reduced pilot visibility during low, slow flight and landing. Recently, brownout has become a high-priority problem for military operations because of the risk to both pilot and equipment. Mitigation of this problem has focused on flight controls and landing maneuvers, but current knowledge and experimental data describing the aerodynamic contribution to brownout are limited. This paper focuses on downwash characteristics of a UH-60 Blackhawk as they pertain to particle entrainment and brownout. Results of a full-scale tuft test are presented and used to validate a high-fidelity Navier-Stokes computational fluid dynamics CFD calculation. CFD analysis for an EH-101 Merlin helicopter is also presented, and its flow field characteristics are compared with those of the UH-60.

Subject Categories:

  • Helicopters
  • Electric Power Production and Distribution
  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE