Droplet Kinetic Energy Research Articles

Long range self-transport of liquid droplets driven by electric field and roughness gradient

It is well known that roughness and charge gradients could be used for droplet self-transport. The key issue is how to synergize the two effects. The uniform density charge can form linearly increasing charge gradient on a roughness gradient surface. Under this condition, the influence on the droplet self-transport under the synergy of these two effects was obtained by statics analysis, and the driving function was presented. An energy equation was constructed to study the conditions for crossing periodic boundaries, and the problem of distance limitation on periodic surfaces due to energy dissipation was solved by converting electric potential into droplet kinetic energy. A periodic roughness gradient surface with K = 0.07 was designed and prepared via 3D printing. Water droplets can be transported over long distances and the maximum velocity increases with charge density up to 46 mm/s. Finally, the effect of different structures on the maximum charge density in the Cassie state was investigated by simulation. The biomimetic structures exhibit great compressive stability, which can increase the surface charge density of droplets in the Cassie state by 3.6 times compared to pillar structures. It can be widely used in the fields of materials science and interface chemistry, etc.

Droplet detachment from a vertical filament with one end clamped

Understanding whether a droplet adheres to or detaches from a flexible filament upon axial impact is of significant interest, particularly in the context of raindrop impact on natural surfaces. This process involves dynamic buckling followed by mode coarsening, dissipating the initial droplet kinetic energy and converting the remaining into elastic energy of the filament. To elucidate this phenomenon, we construct two phase diagrams, one while fixing the filament height and the other the droplet diameter. Notably, we observe that the energy conversion rate is inversely proportional to a Cauchy number, defining the transition between attached and detached droplet in the filament length–falling height diagram. This enables us to derive an expression for the critical falling height as a function of the filament parameters, accounting for the energy conversion rate, which emerges as a key factor for droplet detachment. Published by the American Physical Society 2024

Microbubbles enhance oil-in-water emulsion separation in fibrous coalescers

The principle of fibrous coalescers is to induce the coalescence and growth of small oil droplets in oil-in-water emulsions to achieve oil–water separation. However, they are poorly adaptable to emulsions containing high-viscosity oil. In this study, pressurized air is dissolved in the oil-in-water emulsion, microbubbles are released by reducing the pressure, and the emulsion is subsequently processed through a fibrous coalescer. Adding microbubbles altered the oil removal mechanism within the fibrous bed from oil droplet coalescence and growth to oil droplet–microbubble floc flotation, which significantly improved the emulsion separation efficiency of the fibrous bed, especially in complex emulsions containing surfactants and low salinity. Notably, the decrease in the interfacial energy of the oil droplet–microbubble floc caused oil droplets adhered to fibers to detach and renew quickly. Moreover, the curved interfacial tension increased oil droplet buoyancy and kinetic energy collectively drove the detachment of oil droplets from the fibrous bed. Effective, dynamic anti-fouling of the fibrous bed was able to maintain high throughput during long-term emulsion separation. This study provides a theoretical basis for the industrial application of fibrous coalescers for the treatment of oily wastewater produced during extraction high-viscosity crude oil.

Enhancing crop yield and conserving soil moisture through mulching practices in dryland agriculture

Dryland agriculture requires the efficient utilization of water resources and the implementation of water-conserving technologies. Mulching is a water conservation practice used in arid land areas to preserve soil moisture, control temperature, and minimize soil evaporation rates. Organic mulching minimizes soil deterioration, enhances organic matter, and boosts the soil’s ability to retain water. Mulching can help keep moisture in the root zone, allowing plants to receive water for extended periods. Mulching with composted yard waste led to higher soil nutrient levels, including phosphorus (P), potassium (K), calcium (Ca), and organic matter when compared to uncovered soil. Under plastic mulch, soluble nutrients such as nitrate (NO3−), ammonium (NH4+), calcium (Ca2+), magnesium (Mg2+), potassium (K+), and fulvic acid are released as organic matter decomposes, enhancing the soil’s nutrient availability. Mulching has several advantages for dryland agriculture, such as reducing soil water loss, soil erosion, weed growth, water droplet kinetic energy, and competition for nutrients and water with nearby fields. This review article aimed to demonstrate the effectiveness of ground mulching in water conservation. This is particularly important in arid regions where agricultural sustainability is at risk due to drought, heat stress, and the inefficient use of limited water resources during the cropping season. Ground mulching is essential for minimizing surface evaporation and hence decreasing water loss. This review research thoroughly examines the advantages of organic and synthetic mulches in crop production, as well as their use in the preservation of soil and water resources.

Using 2DVD technology to explore droplet characteristic variations of sprinkler irrigation as affected by a maize canopy

Canopy cover influences the water distribution and droplet characteristics of sprinkler irrigation, creating uncertainty in the design optimization of sprinkler irrigation systems. To evaluate the effects of canopy cover on water distribution and droplet characteristics of sprinkler irrigation, the radial distribution of droplet diameters, velocities, impact angles, shear stresses, and kinetic energies were investigated by an indoor experiment using a two-dimensional video disdrometer (2DVD) with Nelson R33LP low-pressure sprinklers at three operating pressures (100, 200, and 300 kPa), three nozzle diameters (4.4, 4.8, and 5.2 mm), and two growing stages of the maize canopy. Additionally, the water application rates were measured by catch-can devices for each treatment. The results show that small droplets passing through the canopy converge into larger-diameter droplets and large droplets passing through the canopy break up into smaller-diameter droplets. The canopy cover significantly affected droplet kinetic energy and velocity and reduced shear stress by 2.48–96.09 %, which could minimize the risk of soil erosion. Meanwhile, an increase in the leaf area index (LAI) reduced the kinetic energy by 0.26–99.00 %. Canopy cover also had an obvious effect on the irrigation uniformity coefficients (CU). The CU without the canopy exhibited a significant linear correlation with the CU with the canopy. When the irrigation CU without the canopy was 62.00 %, the maize canopy at the jointing stage improved it by 16.62 %, and when the CU without the canopy was 88.47 %, the maize canopy cover at the jointing stage reduced it by 4.68 %. An increase in operating pressure improved the uniformity of the sprinkler by 0.57–151.58 % and reduced shear stress by 2.80–95.11 %. An increasing nozzle size increased the application rate and specific power. This study provides technical support for the design of sprinkler irrigation systems.

Effect of film properties on droplet impact on suspended films

Understanding the dynamics and underlying mechanisms of droplet impact on suspended films is crucial for controlling droplet motion. In this study, we conducted experiments to investigate droplet impact on suspended films and examined the typical phenomena and corresponding Weber number domains. We explored the effects of changing sodium dodecyl sulfate (SDS) concentration and glycerol content on the surface tension and dynamic viscosity of the films. Additionally, we elucidated the characteristics of film deformation and droplet trajectory. An energy analysis was performed, considering the droplet kinetic energy (Ek0), surface energy increment of the film (ΔEfs), and viscous dissipation (Evis). The results demonstrate that as the SDS concentration increases, the upper critical Weber number (Wecru) between bouncing and passing decreases, while the lower critical Weber number (Wecrl) between coalescence and bouncing first decreases and then increases. For droplet bouncing, increasing the SDS concentration makes the films more susceptible to deformation, whereas increasing the glycerol content enhances film rigidity. Moreover, increasing the SDS concentration and glycerol content leads to higher energy losses, resulting in a reduction in the maximum bouncing height (hbdmax). Regarding droplet passing, the passing velocity (Vpd) increases with increasing SDS concentration. For films without SDS, Vpd increases with increasing glycerol content, while for films with SDS, Vpd decreases. The different impact modes are categorized based on the dimensionless energy parameter E* = Ek0/(ΔEfs + Evis). We have successfully predicted the critical height thresholds (Hd0crl and Hd0cru) and established a relationship of We* = f (Re*, Bo*) that aligns well with experimental results.

Water droplet distribution for non-circular sprinkler nozzles

<div><p>Objective: The study sought to investigate the distribution law of the diameter, velocity, and kinetic energy of water droplets in specially designed nozzles. Method: An indoor windless water droplet dispersion test on the PY15 rocker-arm sprinkler was performed using a video raindrop spectrometer at five working pressures: 100 kPa, 150 kPa, 200 kPa, 250 kPa, and 300 kPa. Result: The equal-flow nozzle has the following range: circle > rhombus > ellipse; the shape coefficient of the special-shaped nozzle decreases with increasing outlet diameter and increases with increasing aspect ratio; the diameter of the rhombus nozzle’s water droplet increases radially. Conclusion: Under the same working pressure, the diameter of the water droplet at the end decreases as the form coefficient increases. The wider the outlet’s diameter, the longer the range and the greater the increase in the velocity of the water droplets. The larger the aspect ratio, the shorter the range and the greater the average diameter and velocity of the droplets. The elliptical nozzle has the lowest droplet velocity increase as droplet diameter increases. The impacting kinetic energy and growth range of water droplets per unit volume at the same position decrease as the pressure increases. Along the radial direction, the droplet velocity and diameter are logarithmic, while the droplet kinetic energy and diameter are exponential and linear functions. The relationship between the shape coefficient, outlet diameter, aspect ratio, and droplet distribution characteristics of the shaped nozzle can be simulated using the fitting coefficients of the three droplet distribution prediction models, all of which are above 0.9.</p></div>

Critical factors influencing soil runoff and erosion in sprinkler irrigation: Water application rate and droplet kinetic energy

Critical factors influencing soil runoff and erosion in sprinkler irrigation: Water application rate and droplet kinetic energy

Impact of controlled prewetting on part formation in binder jet additive manufacturing

Binder jetting is an additive manufacturing process that bonds powder through selectively depositing binder by inkjet printing. The part is then extracted and densified by sintering and/or infiltration. The process offers low costs and fast build rates, but properties can be poor due to residual porosity after sintering. The inkjet printing process may contribute to this residual porosity by creating large pores. The droplet kinetic energy ejects some powder particles from the bed and rearranges others. Particle ejection and rearrangement are theorized to create porous regions in binder-jetted parts. In this work, small amounts of moisture are added to the spread powder before printing and the impact on part formation, part properties, and printing parameters measured with varied droplet spacing, droplet velocity, and print frequency. Moisture is added by applying an atomized fluid mixture to the powder between layer spreading and binder printing. The fluid mixture partially evaporates but leaves a stable residue to increase cohesion and enhance imbibition. Moisture addition to the powder increases the range of droplet spacings for line formation while reducing particle ejection, powder rearrangement, and balling in layer and multilayer parts. Excessive moisture addition decreases the effective saturation of printed lines, but saturation in 3D parts is less impacted. Increased surface roughness in the first few layers of a print was also mitigated with prewetting. High-speed X-ray imaging verified prewetting reduction in particle ejection and rearrangement.

Performance transition in droplet-based electricity generator with optimized top electrode arrangements

Harvesting electrical energy from water droplet is a sustainable and promising way to meet challenges in energy scarcity. The water kinetic energy has been successfully harvested into electricity energy by droplet-based electricity generator (DEG). By virtue of its novel transistor-like design with a top electrode, the DEG achieves a high instantaneous power density basing on bulk effect instead of interfacial effect. Despite this, how top electrode arrangement influences the electricity generation as a basic question is still obscure. Here, we study the impact of top electrode arrangement on the output performance of DEG. A transition between open system and closed system is found in the generator when the top electrode arrangement changes at vertical and horizontal direction. Such transition is further analyzed from the working mechanism, droplet dynamic behavior and output performance. Finally, an optimal top electrode arrangement is acquired, which will provide guidance in DEG design. We envision that such optimal top electrode arrangement of DEG will open new pathway for efficiently harvesting water droplet kinetic energy.

Experimental Study on Water Distribution and Droplet Kinetic Energy Intensity from Non-Circular Nozzles with Different Aspect Ratios

(1) Background: In sprinkler irrigation systems, the water distribution and droplet kinetic energy are affected by the shape of the nozzle. In this paper, the effects of working pressure and aspect ratio (L/D) of circular and non-circular nozzles (diamond and ellipse) on water distribution and droplet kinetic energy intensity were investigated; (2) Methods: The hydraulic performance of a PY15 impact sprinkler with circular and non-circular nozzles was assessed under different working pressures, and the droplet diameter, velocity, and kinetic energy intensity were measured by a 2D video disdrometer. Moreover, the coefficient of variation (CV) and form factor (β) were introduced to represent the water distribution and droplet characteristics; (3) Results: The results revealed that, under the same working pressure, the CV of the diamond nozzle was the smallest compared with that of the circular and elliptical nozzles, reflecting a more uniform water distribution. The uniformity of water distribution was the best when the L/D of the elliptical nozzle was the smallest. In general, the larger the outlet diameter, the larger the wetted radius and water application rate. In addition, the smaller the L/D, the smaller the peak water distribution value and the radial increase of the kinetic energy intensity of a single nozzle. The maximum droplet kinetic energy per unit volume of the elliptical nozzle was the smallest compared with that of the circular and diamond nozzles. The circular nozzle at 200 kPa and the diamond and elliptical nozzles at 100 kPa obtained the highest uniformity coefficients of combined kinetic energy intensity distribution, which were 55.93% (circular), 67.59% (diamond), and 57.78% (elliptical) when the combination spacings were 1.0 R, 1.1 R and 1.2 R, and 1.0 R, respectively. Finally, the fitting function of unit volume droplet kinetic energy, distance from the nozzle, L/D, and working pressure of non-circular nozzles was established, and a fitting coefficient of 0.92 was obtained, indicating that the fitting equation was accurate; (4) Conclusions: At low working pressures, the elliptic and diamond nozzles showed better water distributions than the circular nozzle. The distal average droplet diameters of the sprinkler with non-circular nozzles were found to be smaller than those produced by the circular nozzle.

Phase, pressure and velocity evolution and atomization characteristics of multiple Faraday waves in ultrasonic atomization: experiments and simulations

• Numerical simulation study of the multiple Faraday wave's evolutions. • Pressure difference in the Faraday wave is the internal driving force of fluid flow. • The Faraday wave unstable evolution is essentially an energy conversion process. • The effect of liquid density on atomization characters is predicted by simulation. Ultrasonic atomization has attracted a great deal of attention from the industrial and research communities in recent years. However, current research lacks attention to the internal pressure and velocity fields in the unsteady evolution of multiple Faraday waves, leading to an insufficient understanding of the ultrasonic atomization mechanism. Here, we use computational fluid dynamics to conduct a detailed study of multiple Faraday waves under ultrasonic frequency vibrations, including phase, pressure, and velocity field evolution, and atomization characteristics. In the middle of the ligament, a pressure peak point induced by surface tension induces the capillary pinch-off phenomenon. Essentially, Faraday wave instability evolution is the process of storing, consuming kinetic energy, then converting it into pressure potential energy, and finally into droplet surface energy and kinetic energy. The effects of different parameters (vibration amplitude, vibration frequency, liquid surface tension, viscosity, density, and liquid film thickness) on the atomization characteristics (amplitude threshold, atomization time, and droplet size) are related to this energy evolution. This study provides a new physical explanation of the unstable evolution mechanism of multi-Faraday waves from the perspective of energy conversion, improving the scientific validity of ultrasonic atomization techniques in applications.

Hydrodynamic analysis of the energy dissipation of droplets on vibrating superhydrophobic surfaces

In this paper, experimental and numerical methods are presented to describe the hydrodynamic process of the vibration-induced detachment of a droplet from a superhydrophobic surface. We conduct the investigation of the droplet dynamics under various vibration and impact parameters, from an energy conversion perspective. In particular, the energy dissipation that occurs following the droplet impact is analyzed quantitatively. We identify three viewpoints on vibration-induced droplets. Firstly, the phase angle is the dominant factor in characterizing the droplet morphology evolution and energy dissipation on a vibrating surface. The law governing the initial phase angle is affected by the vibration frequency, while the intensity is affected by the vibration amplitude. Secondly, the energy dissipation is positively correlated with the maximum spreading diameter and impact velocity. A larger initial diameter tends to produce a longer contact time. Finally, the central jet formation depends heavily on the upward velocity of the concave liquid, under the peculiar morphology of a vibration-induced droplet. For all these effects, up to 60% of the total energy is squandered during impact, while the surface energy remains almost constant. Much of the droplet's kinetic energy is lost in resisting the viscous force of the substrate.

Mechanics of droplet flow / solidification and film deformation / fracture

In industrial applications, the coatings of materials are an important consideration, particularly the fracture and elastic-plastic mechanics of coating materials. This is an area of focus for researchers in the Inoue Sakaguchi Laboratory, Tokyo Institute of Technology, Japan, where Associate Professor Motoki Sakaguchi and the team are investigating the stress and strain evolution during the solidification and adhesion process of coating materials. They are doing this by conducting model experiments using paraffin wax, which is enabling them to investigate the individual effects of different experimental variables, including droplet materials, droplet temperature, droplet kinetic energy, substrate temperature and substrate roughness. In a current project, Sakaguchi is exploring the fundamental processes involved in residual stress development in thermal barrier coatings during thermal spray procedures. For this, he and the team have developed a model experiment that allows them to simplify the thermal spray using a paraffin wax with a low melting point and, in doing so, the researchers can monitor and precisely record the deposition process of each splat in the thermal spray. Sakaguchi hopes the research will help improve thermal spray technology and, ultimately, lead to improved, longer-lasting components and equipment in industrial products.

Mechanics of droplet flow/solidification and film deformation/fracture

In industrial applications, the coatings of materials are an important consideration, particularly the fracture and elastic-plastic mechanics of coating materials. This is an area of focus for researchers in the Inoue Sakaguchi Laboratory, Tokyo Institute of Technology, Japan, where Associate Professor Motoki Sakaguchi and the team are investigating the stress and strain evolution during the solidification and adhesion process of coating materials. They are doing this by conducting model experiments using paraffin wax, which is enabling them to investigate the individual effects of different experimental variables, including droplet materials, droplet temperature, droplet kinetic energy, substrate temperature and substrate roughness. In a current project, Sakaguchi is exploring the fundamental processes involved in residual stress development in thermal barrier coatings during thermal spray procedures. For this, he and the team have developed a model experiment that allows them to simplify the thermal spray using a paraffin wax with a low melting point and, in doing so, the researchers can monitor and precisely record the deposition process of each splat in the thermal spray. Sakaguchi hopes the research will help improve thermal spray technology and, ultimately, lead to improved, longer-lasting components and equipment in industrial products.

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

AbstractProper droplet diameter and kinetic energy can effectively reduce the risk of soil erosion during low‐pressure sprinkler irrigation. In this study, we comprehensively evaluated the radial distributions of droplet diameter, velocity, kinetic energy, kinetic energy per unit droplet volume, and specific power for three common low‐pressure sprinklers, i.e. Nelson D3000, R3000 and Komet KPT, with two operating pressures (103 and 138 kPa) and three nozzle outlet diameters (3.97, 5.95 and 7.94 mm). Additionally, the relationships between these droplet characteristic parameters were analysed. Overall, the maximum values of five characteristic parameters were observed at the end of the jet under various treatments. Although R3000 had a larger droplet diameter (0.10–6.42 mm) and kinetic energy (1.08 × 10−10–8.59 × 10−3 J) distribution range than D3000 and KPT, the D3000 specific power (mean value of 0.4274 W m−2) was the highest of the three sprinklers. Therefore, KPT was suggested more in low‐pressure sprinkler irrigation than in the other two sprinklers because its application rates were reduced along the radial direction. In addition to selecting a suitable sprinkler type for minimizing specific power, determining a reasonable sprinkler spacing was also significant (P < 0.01). Furthermore, a universal specific power model with an appropriate accuracy (RMSE = 0.011 W m−2, NRMSE = 29%) was proposed. This study provides a key basis for the selection and combination of low‐pressure sprinklers.

Numerical study on the bouncing dynamics of droplets impacting on a macro-textured superhydrophobic surface

The contact time of droplet impacting on surfaces involves in the extent of transformation between the droplet's surface energy and kinetic energy. Based on the axisymmetric assumption, the theoretical prediction of the contact time is regardless of impacting velocity of the droplet. In order to further reduce the contact time, a novel superhydrophobic surface with a macro-textured ridge was proposed by Bird et al [1]. to generate asymmetric bouncing behaviors of a droplet. In the present study, a detailed numerical simulation was carried out to investigate the bouncing dynamics of the impacting process of droplets on surface with a macro-textured ridge at various Weber (We) numbers by adopting many-body dissipative particle dynamics (MDPD). The bouncing dynamics of droplets can be mainly divided into two types, i.e. jug-like behavior with asymmetric retracting velocity and wing-like behavior with rotation of the sub-droplets. The angular velocity of droplets during rebounding is crucial for the corresponding contact time, where the step-like angular velocity at different We numbers are observed. Finally, a brief theoretical analysis was provided to reveal the critical We number and the limitation of contact time for the wing-like state. This work is helpful in understanding the reduction of contact time for droplet impacting on a macro-textured superhydrophobic surface, meanwhile, it offers a guidance for surface structural design where enough angular velocity of droplets should be produced during rebounding if the contact time needs to be decreased.

Mechanics of droplet flow / solidification and film deformation / fracture

In industrial applications, the coatings of materials are an important consideration, particularly the fracture and elastic-plastic mechanics of coating materials. This is an area of focus for researchers in the Inoue Sakaguchi Laboratory, Tokyo Institute of Technology, Japan, where Associate Professor Motoki Sakaguchi and the team are investigating the stress and strain evolution during the solidification and adhesion process of coating materials. They are doing this by conducting model experiments using paraffin wax, which is enabling them to investigate the individual effects of different experimental variables, including droplet materials, droplet temperature, droplet kinetic energy, substrate temperature and substrate roughness. In a current project, Sakaguchi is exploring the fundamental processes involved in residual stress development in thermal barrier coatings during thermal spray procedures. For this, he and the team have developed a model experiment that allows them to simplify the thermal spray using a paraffin wax with a low melting point and, in doing so, the researchers can monitor and precisely record the deposition process of each splat in the thermal spray. Sakaguchi hopes the research will help improve thermal spray technology and, ultimately, lead to improved, longer-lasting components and equipment in industrial products.

Comparisons of Spray Characteristics between Non-circular and Circular Nozzles with Rotating Sprinklers

HighlightsExperiments were conducted to investigate the hydraulic performance of the solid-set rotating sprinkler.The effects of nozzle shape and working pressure on the droplet characteristics and kinetic energy of the rotating sprinkler were analyzed.The circular nozzle has a large wetting radius and large droplet size.Use of a non-circular nozzle could result in higher irrigation uniformity and lower kinetic energy imparted to the soil surface by water droplets under low working pressures.Abstract. Reducing the working pressure of sprinklers can effectively reduce sprinkler irrigation energy requirements. However, the reduction in working pressure and variation of nozzle shape inevitably lead to changes in the hydraulic performance of the sprinkler. To evaluate the spray characteristics of selected non-circular (the shape of the nozzle opening was asymmetric) and circular nozzles at low pressure, experiments were conducted to investigate the effects of working pressure, nozzle shape, and nozzle diameter on flow rate, radius of throw, water application rate, droplet size, droplet velocity of the rotating sprinkler, and kinetic energy of the water droplets impacting on the soil surface. The coefficients of irrigation uniformity were calculated for the non-circular and circular nozzles under different rectangular sprinkler spacing and working pressures. The results show that the flow rates of the non-circular and circular nozzles were equal under the same working pressure and with the same nozzle size, while the throw radius of the circular nozzle was longer than that of the non-circular nozzle. The circular nozzle produced a larger droplet size than the non-circular nozzle did. Since the droplet size and kinetic energy per unit droplet volume increased along the radius of throw, and the peak water application rate of the circular nozzle was located near the perimeter of the radius of throw, the peak specific power impact on the soil surface by the water droplets of the circular nozzle was greaterspecifically, 1.26 to 1.97 times that of the non-circular nozzle. With the increase in working pressure, the peak values of specific power and water application rate decreased. The irrigation uniformity coefficients of the non-circular and circular nozzles were more than 85% within the recommended pressure range of the manufacturer when the sprinkler spacing was less than 11 m. It was easier to obtain higher irrigation uniformity and lower impact kinetic energy under low working pressure when using a non-circular nozzle. Keywords: Application rate, Irrigation uniformity, Kinetic energy, Sprinkler irrigation, Working condition.

Impacting Droplet Can Mitigate Dust from PDMS Micro-Post Array Surfaces

In this paper, the impact mechanisms of a water droplet on hydrophobized micro-post array surfaces are examined and the influence of micro-post arrays spacing on the droplet behavior in terms of spreading, retraction, and rebounding is investigated. Impacting droplet behavior was recorded using a high-speed facility and flow generated in the droplet fluid was simulated in 3D geometry accommodating conditions of the experiments. Micro-post arrays were initially formed lithographically on silicon wafer surfaces and, later, replicated by polydimethylsiloxane (PDMS). The replicated micro-post arrays surfaces were hydrophobized through coating by functionalized nano-silica particles. Hydrophobized surfaces result in a contact angle of 153° ± 3° with a hysteresis of 3° ± 1°. The predictions of the temporal behavior of droplet wetting diameter during spreading agree with the experimental data. Increasing micro-post arrays spacing reduces the maximum spreading diameter on the surface; in this case, droplet fluid penetrated micro-posts spacing creates a pinning effect while lowering droplet kinetic energy during the spreading cycle. Flow circulation results inside the droplet fluid in the edge region of the droplet during the spreading period; however, opposing flow occurs from the outer region towards the droplet center during the retraction cycle. This creates a stagnation zone in the central region of the droplet, which extends towards the droplet surface onset of droplet rebounding. Impacting droplet mitigates dust from hydrophobized micro-post array surfaces, and increasing droplet Weber number increases the area of dust mitigated from micro-post arrays surfaces.