Packed towers are widely used in process industries in unit operations, e.g., distillation, absorption, water cooling, and catalytic gas-liquid reactions in which flowing gas and liquid need to be brought into intimate contact. The liquid is introduced through a distributor at the top of the packed bed and it trickles down over the particles in the form of rivulets or films. An engineering hydrodynamic model was developed for rivulet flow, which can be extended to explain wetting efficiency in packed beds. The width of rivulet flowing down an inclined plane surface was measured as a function of liquid flow rate and correlated through friction factor. The correlation for rivulet width with rivulet flow rate on inclined plane surfaces was adopted to liquid flow down the packing elements in a packed bed. Literature data showed that wetting efficiency in packed beds is dominated by gravity and inertial forces; liquid-surface interaction characterized by contact angle influences wetting efficiency. This is an abstract of a paper presented at the 2013 AIChE Spring Meeting & 9th Global Congress on Process Safety (San Antonio, TX 4/28-5/2/2013).