Kinetic energy in sprinkler irrigation: different sources of drop diameter and velocity

Abstract

Sprinkler kinetic energy has been linked to a number of problems in irrigated fields. This work presents the characterization of sprinkler drop kinetic energy and specific power from low-speed photographic drop data using a commercial impact sprinkler and three operating pressures. The spatial variability of specific power (W m -2 ) was assessed for different sprinkler spacings, showing different patterns in rectangular and triangular spacings. The specific power uniformity coefficient ranged from 38 % to 77 %, depending on sprinkler spacing and operating pressure. An attempt was made to characterize specific power from estimated (measured diameter and estimated velocity) and simulated data (using a ballistic model). While estimated data produced adequate results, simulated data resulted in a large overestimation. Discrepancies in kinetic variables between measured and simulated drop data permit to conclude that it is important to continue experimental drop characterization efforts as well as sprinkler simulation model development.

Comprehensively evaluating and modelling droplet diameters and kinetic energies of low‐pressure sprinklers

“…Droplet diameter and velocity together affect droplet kinetic energy. These results were comparable to Bautista‐Capetillo et al’s (2012) findings for a VYR35 sprinkler with a nozzle diameter of 4.8 mm.…”

“…With increasing distance from the sprinkler, the kinetic energy range of KPT always maintained a robust expansion trend, while those of the other two sprinklers expanded very little until the middle of the spray jet. Regarding D3000 and R3000, their average maximum droplet kinetic energies at 5 m were only 1.32 × 10 −4 J larger than those at 2 m. This was in line with the result obtained by Bautista‐Capetillo et al, (2012) using a VYR35 impact sprinkler, i.e. the range in the droplet kinetic energy was very similar within 3–6 m from the sprinkler.…”

“…Moreover, it was clear that the kinetic energy ranges under different nozzle diameters were generally larger at 103 kPa than at 138 kPa. As mentioned above, both the droplet diameter and velocity range decreased as the working pressure increased, which seemed to be the primary cause of this relationship (Bautista‐Capetillo et al, 2012).…”

A modified particle tracking velocimetry technique to characterize sprinkler irrigation drops

“…When water drops are originated in sprinkler irrigation systems, their characterization permits to assess and limit their potential negative effects on the soil surface (erosion or mechanical compaction). Additionally, the analysis of water droplets can lead to the optimization of irrigation performance indicators, such as uniformity and efficiency, under different environmental, operational, and hardware conditions (Keller and Bliesner 1990;Bautista-Capetillo et al 2012;Salinas-Tapia et al 2014). The assessment of sprinkler irrigation systems requires this type of analyses to understand the processes and to conserve water, soil and energy.…”

“…When large, fast-moving drops impact the soil surface, a reduction in water infiltration rate has been observed due to a change in the physical properties of the soil surface, potentially causing crusting, runoff and erosion (King and Bjorneberg 2012). A number of researchers have found strong relations between these phenomena and the kinetic energy of large water drops (Thompson and James 1985;Kincaid 1996;Basahi et al 1998;Bautista-Capetillo et al 2012, Ge et al 2016.…”