The spreading of Newtonian liquid drops after impact with a solid m#ace is reported for a range of liquid and surface properties, drop diameters, and impact velocities. Results for liquid viscosities up to 300 mPa-s are given. For a given drop diameter and velocig, a range of liquid viscosities result in splashing even for smooth su#aces. The maximum spread radius, made dimensionless with the drop radius, is correlated as RE,, = 0.61 (Re20h)0.'66, where Re and Oh are the Reynolds and Ohnesorge numbers, respectively. A model is proposed to account for inertial, viscous, and su#ace tension forces on the maximum spread radius. Good agreement is found between the model and experimental data from several sources.

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The interaction between drop impact and vapor breakthrough for several kinds of air-permeable fabric composites (an outer shell with an adsorbent liner) is determined under convective flow conditions. Vapor breakthrough is measured using methyl salicylate, a chemical agent simulant, for static and dynamic liquid drop placement on either the shell fabric alone or in combination with an activated carbon-loaded foam liner backing. Vapor concentration, detected by means of a photo-ionizer, is used to determine breakthrough curves, while image analysis provides a quantitative characterization of the impact behavior of the liquid drops by measuring liquid spreading. splashing, and breakthrough. Drop impact velocities up to 6 m/s are measured on cotton/Kevlar®/nylon and cotton/nylon twill weave outer shell fabrics. For static drops, fabric composites with an outer wicking fabric give much lower total vapor breakthrough than do nonwicking fabrics, whereas for dynamic drops at subterminal impact velocities, the difference between nonwicking and wicking shell fabrics is reduced because of surface spreading and splashing. There is an inverse correlation between wetted area and vapor breakthrough due to localized vapor saturation of the adsorbent liner fabric. Below a critical drop velocity of 4.5 m/s, there is no direct liquid penetration through the shell fabric.