Effect of Yaw Angle and Ambient Wind on Fabric Penetration of a Simulated Sleeve.

摘要

As part of a program to develop a systematic method to test and quantify Individual Protective Equipment effectiveness, a methodology was developed to test component (sleeve) specimens at elevated wind speeds in the Naval Aerodynamic Test Facility wind tunnel. Tests were conducted to determine the azimuthal pressure characteristics of a circular cylinder with a simulated fabric sleeve. A support screen was placed between the fabric and the circular cylinder to create an idealized flow condition with a constant air gap. With the constrained sleeve, the pressure coefficient around the model inner core was measured and found to be nearly invariant with azimuth and wind velocity and had a value of approximately -0.5. Fabric pressure drop was measured as a variation with model azimuth and found to exhibit a net inflow for angles less than 30??. Above this value the pressure was positive indicating a net outflow. Particle penetration was measured for three yaw angles and at four wind speeds. In general the maximum particle penetration was found to increase with increasing wind velocity and decrease with increasing yaw angle. The results were found to be consistent and repeatable. Fabric pressure differential/fabric face velocity was found to be a parameter, but not the sole parameter, to quantify particle penetration performance. Further research or analysis may be needed quantify this complex phenomenon completely.