Evaluation of 5-cm Agent Fate Wind Tunnel Velocity Profiles
Abstract
Velocity profiles measured in 5-cm Agent Fate wind tunnels have been evaluated for conformance to specified profiles. These facilities are used to determine evaporation and desorption rates of chemical warfare agents (CWA) from various surface materials. The specified profiles represent an atmospheric boundary layer for velocity conditions of 6, 3, and 0.5 m/s at a height of 2 m. The 5-cm tunnels are designed to duplicate the part of this profile closest to the surface to provide realistic conditions for agent volatilization. The friction velocity that characterizes the flow in the wall layer of turbulent boundary layers was obtained for each profile from the semi-logarithmic region of the velocity distribution. Results show that the average friction velocities at the two highest velocities are slightly below that of the predetermined values by 7.5 and 8.4%, respectively. This difference corresponds to a systematic error in agent evaporation rate of 4-5%. Other characteristics of the velocity distributions (e.g., the intercept in the semi-logarithmic coordinates) varied significantly from the zero pressure gradient turbulent boundary layer. The low velocity measurements were found to be essentially laminar with turbulence intensity measurements confirming this laminar character.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2007
- Accession Number
- ADA472909
Entities
People
- James E. Danberg
Organizations
- Leidos