296 J. Eng . Te c hno l. Sc i., Vo l. 47, No . 3, 2015, 296-305 Received March 12 th , 2014, 1 st Revision October 16 th , 2014, 2 nd Revision November 27 th , 2014, 3 rd Revision March 17 th , 2015, Accepted for publication May 11 th , 2015. Copyright ©2015 Published by ITB Journal Publisher, ISSN: 2337-5779, DOI: 10.5614/j.eng.technol.sci.2015.47.3.5 Analytical Study of Wind Influence on In-Flight Sprinkler Droplets Frank Agyen Dwomoh 1,2* , Yuan Shouqi 1 & Li Hong 1 1 Research Centre of Fluid Machinery Engineering and Technology, Jiangsu University, 212013, Zhenjiang, Jiangsu, P. R. China 2 School of Engineering, Koforidua Polytechnic, P.O. Box 981 Ghana * Email: agyen2007@gmail.com Abstract. An analytical model to describe the dynamics of in-flight droplets is presented in this paper to augment information on wind influence on travel distance of in-flight sprinkler droplets. The model is ballistic-theory based. It employs a relatively simple, wide-range empirical relationship between drag coefficient and Reynolds’ number to replace the several sets of relations for a specified range of Reynolds numbers. The fourth-order Runge-Kutta numerical integration techniques were used to solve the trajectory equations. A modified exponential model for droplet size distribution was used during the simulation. Comparative analysis showed that agreement exists between the predictions of this model and that of earlier models. Droplets with a diameter smaller than 0.1 mm travelled farthest. Within the droplet range of 0.5 mm to 4.5 mm, as droplet diameter increased, travelled distance increased with increasing wind speed. The extent of drift increased sharply within the droplet range of 0.5 mm to 0.05 mm and increased mildly for droplet diameters greater than 0.5 mm. The model also attempts to identify droplets that are likely to contribute to drift loss and those that have a high probability of contributing only to distortion of the distribution pattern. Keywords: analytical model; droplet drift; distribution pattern; simulation; sprinkler droplets; traveled distance; wind influence. 1 Introduction The influence of wind during sprinkler irrigation pose challenges that need attention especially in this era of water conservation towards a sustainable use of resources. Most sprinklers apply water to the ground by projecting water jets into the air at high velocity, which later fall down as water droplets. Under windy conditions, in-flight sprinkler water droplets may impact the ground or plant canopy, experience droplet evaporation or be wind drifted [1-3]. Sprinkler droplet travel under no-wind condition is undisturbed and thus a characteristic of the sprinkler nozzle for a given operation configuration. If droplets travel beyond their characteristic distances for the same sprinkler