The Effects of Reynolds Number Variation on Measurement of Limb Flail Forces and Moments
Abstract
The Air Force Medical Research Laboratory (AFAMRL) has used wind tunnels to conduct research on the problem of windblast protection since 1971. This research has been focused upon the measurement of aerodynamic forces acting on the human body during and after emergency egress from aircraft using volunteer human subjects, anthropomorphic dummies, and scale models. The use of scale models in the wind tunnel has potential problems associated with attempting to create dynamically similar airflow and thus aerodynamically similar forces. Dimensional analysis has shown that the force coefficient for a body of given orientation and shape is a function of the Reynolds number and Mach number provided that parameters such as surface roughness, stream turbulence, and the presence of other bodies in the vicinity are not neglected. Variations in Reynolds number might cause variations in the type and thickness of the airflow surrounding the crewmember/seat combination. This, in turn, can affect the upstream flow separation point in front of a bluff body such as the crewman/seat, and thereby affect the magnitude of the forces acting on various segments of the body. The influence of these factors must be known when using scale model data for full-scale applications. Therefore, AFAMRL conducted wind tunnel tests using 1/2-scale models to determine the effects of Reynolds number variation on aerodynamic forces acting on a crewmember during emergency escape or after inadvertent canopy loss.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1985
- Accession Number
- ADA359977
Entities
People
- Lawrence J. Specker
Organizations
- Armstrong Laboratory