Droplet Deformation Research Articles

Molecular dynamics of deformation and fragmentation processes in liquid droplets under pulsed electric field

The deformation and breakup of droplets are widely observed in various aspects of production and daily life. Using molecular dynamics simulations, this study primarily investigated the deformation and breakup of droplets in a nitrogen environment under pulsed electric fields of different frequencies. The results indicate that the droplet deformation undergoes periodic changes under the influence of the pulsed electric field. At equivalent electric field strengths, droplets are more likely to break under a 6.25 GHz pulsed electric field compared to a 25 GHz pulsed electric field, where droplet deformation remains stable without breaking. At every frequency, the bond energy of water molecules consistently decreases. The solvent-accessible surface area changes with the electric field at 6.25 GHz. Furthermore, the minimum value of hydrogen bond quantity reached under high-frequency pulsed fields is higher than that under low-frequency fields. The change in hydrogen bond quantity is inversely proportional to the solvent-accessible surface area. These findings provide insights into the microscopic mechanisms of droplet deformation and breakup, offering a reference for future studies.

Bouncing dynamics of binary equal-sized high-viscosity molten glass droplets in head-on collisions

Despite extensive research on head-on droplet collisions over the past decades, detailed investigations into the bouncing behavior of high-viscosity droplets, such as molten glass droplets, are still scarce. In this study, a volume-of-fluid method coupled with dual marker functions is employed to simulate the collision dynamics of molten glass droplets. The results show good agreement with experimental observations in both spatial and temporal dimensions. Theoretical analysis reveals a critical Weber number of 22 for bouncing and coalescence of molten glass droplets with a diameter of 100 μm. Below this threshold, we examine the bouncing behavior across various Weber numbers, categorizing the process into four distinct stages: mutual proximity, radial expansion, suction separation, and reverse separation, and providing a detailed analysis of velocity, pressure, and energy at each stage. As the Weber number increases, vortices sequentially emerge at 4, 8, 12, and 16, suggesting a strong correlation between droplet deformation and vortex generation. At lower Weber numbers, the air film pressure between droplets transitions smoothly between radial expansion and suction separation. However, between Weber numbers 9 and 22, a distinct concave pressure phenomenon is observed during suction separation. Pressure chattering occurs at the beginning of radial expansion and the end of suction separation. Furthermore, the results indicate that the cumulative viscous dissipation energy consistently approaches half of the initial kinetic energy, irrespective of the Weber and Ohnesorge numbers.

Numerical analysis of the interaction between a droplet and an air boundary layer

The deformation and movement of droplets are widely utilized in many industrial applications. The present work investigates the evolution of a single droplet interacting with an air boundary layer numerically and validated by wind tunnel experiments. The volume of fluid method is employed to study the interaction from the micro-perspective. The influences of airflow velocity, droplet size, and depression angle on interactions are comprehensively discussed. The outcomes indicate that droplet diameter and airflow velocity significantly influence the interaction. Based on the morphological evolution of the droplets, the regimes of the interaction can be classified into three categories. It is shown that the airflow velocity, depression angle, and droplet diameter influence the droplet maximum streamwise spreading length. Furthermore, only the airflow velocity and droplet diameter influence the maximum height. The scaling law for the maximum streamwise spreading factor is revealed. Finally, the velocity profile of the boundary layer above the droplet maximum height is also analyzed, revealing a power-law relationship in its curve. These results provide valuable insight for further investigation on the droplet–air boundary layer interaction.

A hybrid lattice Boltzmann and finite difference method for two-phase flows with soluble surfactants

A hybrid method is developed to simulate two-phase flows with soluble surfactants. In this method, the interface and bulk surfactant concentration equations of diffuse-interface form, which include source terms to consider surfactant adsorption and desorption dynamics, are solved in the entire fluid domain by the finite difference method, while two-phase flows are solved by a lattice Boltzmann color-gradient model, which can accurately simulate binary fluids with unequal densities. The flow and interface surfactant concentration fields are coupled by a modified Langmuir equation of state, which allows for surfactant concentration beyond critical micelle concentration. The capability and accuracy of the hybrid method are first validated by simulating three numerical examples, including the adsorption of bulk surfactants onto the interface of a stationary droplet, the droplet migration in a constant surfactant gradient, and the deformation of a surfactant-laden droplet in a simple shear flow, in which the numerical results are compared with theoretical solutions and available literature data. Then, the hybrid method is applied to simulate the buoyancy-driven bubble rise in a surfactant solution, in which the influence of surfactants is identified for varying wall confinement, density ratio, Eotvos number and Biot number. It is found that surfactants exhibit a retardation effect on the bubble rise due to the Marangoni stress that resists interface motion, and the retardation effect weakens as the Eotvos or Biot number increases. We further show that the weakened retardation effect at higher Biot numbers is attributed to a decreased non-uniform effect of surfactants at the interface. By comparing with the Cahn-Hilliard phase-field method, we also show that the present method conserves the mass for each fluid, improves numerical stability especially at high density ratio and Eotvos number, and does not need the selection of free parameters, thus breaking the limitations of the existing method.

Numerical study of effective parameters on deformation and coalescence of ferrofluid droplets under uniform magnetic field

This research examines different numerical techniques for modeling ferrofluids in a non-magnetic liquid subjected to homogeneous and steady magnetic field. It particularly compares the conservative level set method with the Volume of Fluid (VOF) and Simple Coupled Level Set and Volume of Fluid (SCLSVOF) methods. By comparing these methods with experimental data, we established the superiority of the utilized method in this study. Several case studies were conducted to evaluate how a homogeneous magnetic actuation affects ferrofluid dynamics, considering parameters such as initial droplet size, surface tension coefficient, and magnetic susceptibility. Additionally, the study explored the coalescence of two falling ferrofluid droplets under the combined effects of an external magnetic field and gravity. The conservative level set method was shown to be extendable to three-dimensional environments, unlike the standard level set method. The novelty of this work lies in demonstrating that the conservative level set method is particularly effective for ferrofluids, accurately capturing their complex dynamics. The main novelty of this article lies in demonstrating the precision of Conservative Level Set Method while utilizing a reduced number of equations compared to other works. This reduction in complexity enhances the method's efficiency without compromising precision, making it especially suited for applications requiring both speed and accuracy, such as model-based control systems.

Impact of density ratio on droplet dynamics in pulsating flow

Secondary atomization is extensively studied by investigating a droplet subjected to a steady air/gas stream. However, droplets are often subjected to unsteady or pulsating flows, such as in aero-engines or rockets, because of thermo-acoustic instabilities in the combustion chambers. The investigation focuses on the droplet dynamics and breakup in a pulsating flow for a range of density ratios (ρr), 1000 to 10, under sinusoidal airflow of different amplitudes and frequencies as compared to the dynamics in a steady flow. The volume of fluid multiphase model tracks the liquid–gas interface, and the governing equations are solved using the finite volume method. The two-dimensional axisymmetric pulsating simulations demonstrate accuracy comparable to the corresponding three-dimensional simulations at a much lower computational cost and are used for parametric studies. The droplets under the pulsating flow show a wavy surface, and larger vortex structures are observed during the deceleration period. At a high-density ratio (1000), pulsating flow enhances droplet deformation for a faster breakup, with the flow amplitude having more impact than its frequency. For a medium-density ratio (100), where breakup occurs under steady flow, droplet breakup is inhibited in the pulsating flow at low amplitude and high frequency. In the case of a low-density ratio (10), there is no breakup under steady flow, but pulsating flow promotes breakup, except at low amplitude and high frequency. The droplet breakup is always achieved for the highest amplitude, while lower frequencies push the liquid mass from the center of the droplet to the rim.

Progressive evolution of the viscous dissipation mechanism from the macroscale to the nanoscale

Recent studies of viscous dissipation mechanisms in impacting droplets have revealed distinct behaviours between the macroscale and nanoscale. However, the transition of these mechanisms from the macroscale to the nanoscale remains unexplored due to limited research at the microscale. This work addresses the gap using the many-body dissipative particle dynamics (MDPD) method. While the MDPD method omits specific atomic details, it retains crucial mesoscopic effects, making it suitable for investigating the impact dynamics at the microscale. Through the analysis of velocity contours within impacting droplets, the research identifies three primary contributors to viscous dissipation during spreading: boundary-layer viscous dissipation from shear flow; rim geometric head loss; and bulk viscous dissipation caused by droplet deformation. This prompts a re-evaluation of viscous dissipation mechanisms at both the macroscale and nanoscale. It reveals that the same three kinds of dissipation are present across all scales, differing only in their relative intensities at each scale. A model of the maximum spreading factor (βmax) incorporating all forms of viscous dissipation without adjustable parameters is developed to substantiate this insight. This model is validated against three distinct datasets representing the macroscale, microscale and nanoscale, encompassing a broad spectrum of Weber numbers, Ohnesorge numbers and contact angles. The satisfactory agreement between the model predictions and the data signifies a breakthrough in establishing a universal βmax model applicable across all scales. This model demonstrates the consistent nature of viscous dissipation mechanisms across different scales and underscores the importance of integrating microscale behaviours to understand macroscale and nanoscale phenomena.

Numerical Analysis of the Cell Droplet Loading Process in Cell Printing

Cell printing is a promising technology in tissue engineering, with which the complex three-dimensional tissue constructs can be formed by sequentially printing the cells layer by layer. Though some cell printing experiments with commercial inkjet printers show the possibility of this idea, there are some problems, such as cell damage due the mechanical impact during cell direct writing, which include two processes of cell ejection and cell landing. Cell damage observed during the bioprinting process is often simply attributed to interactions between cells and substrate. However, in reality, cell damage can also arise from complex mechanical effects caused by collisions between cell droplets during continuous printing processes. The objective of this research is to numerically simulate the collision effects between continuously printed cell droplets within the bioprinting process, with a particular focus on analyzing the consequent cell droplet deformation and stress distribution. The influence of gravity force was ignored, cell droplet landing was divided into four phases, the first phase is cell droplet free falling at a certain velocity; the second phase is the collision between the descending cell droplet and the pre-existing cell droplets that have been previously printed onto the substrate. This collision results in significant deformation of the cell membranes of both cell droplets in contact; the third phase is the cell droplet hitting a rigid body substrate; the fourth phase is the cell droplet being bounced. We conducted a qualitative analysis of the stress and strain of cell droplets during the cell printing process to evaluate the influence of different parameters on the printing effect. The results indicate that an increase in jet velocity leads to an increase in stress on cell droplets, thereby increasing the probability of cell damage. Adding cell droplet layers on the substrate can effectively reduce the impact force caused by collisions. Smaller droplets are more susceptible to rupture at higher velocities. These findings provide a scientific basis for optimizing cell printing parameters.

Effects of oil-water interfacial properties on protein structuring and droplet deformation in high moisture meat analogues containing oil

Adding oil to high moisture meat analogues (HMMA) can increase juiciness, and can be achieved by incorporating emulsion droplets during extrusion. Since these droplets can coalesce when subjected to high shear, selecting appropriate emulsion stabilisers is important. For several commercial plant-protein emulsion stabilisers, it was investigated how oil-water interfacial mechanical properties affect droplet deformation and protein structuring in extrusion of HMMAs. Emulsions with 10 wt% or 15 wt% oil, stabilised by potato protein isolates (POPI-1 (Rich in patatin) and POPI-2 (rich in protease inhibitor)) and pea protein isolate PPI, were used to make extrudates with 5.7 wt% and 8.5 wt% oil, respectively. In 8.5 wt%-extrudates, POPI-2 had the most oil leakage from the cooling die, while PPI had the smallest amount despite having softer and more stretchable interfaces. Blade-cutting tests showed the highest maximum force for 8.5 wt%-extrudates with POPI-1, likely because POPI-1 formed the stiffest interfaces. Tensile stress testing showed the largest fracture strain in 8.5% wt%-extrudates with PPI, corresponding to its longer wedge length. Multiphoton excitation microscopy was used to visualise the extrudates protein structure and oil droplets. This showed that droplets near the surface of the extrudate were less deformed than droplets in the centre. There were only small differences between protein stabilisers regarding oil droplet deformation, indicating droplet deformation was dominated by deformation of the protein matrix. The O/W interfacial properties significantly affected oil leakage, cutting force, and tensile strength of extrudates. These results are important to consider when designing emulsions for HMMAs processed by extruders.

Dramatic droplet deformation through interfacial particles jamming

Droplets of one fluid in a second, immiscible fluid are typically spherical in shape due to the interfacial tension between the two fluids. Shear forces can lead to droplet deformation when they are subjected to flow, and these effects can be further modified when the droplet is stabilized by a surfactant due to a flow-induced gradients in the surfactant concentration. An alternative method of stabilizing droplets is through the use of colloidal particles, whose stabilization behavior is intrinsically different from molecular surfactants. Under the same flow condition, a gradient of particle concentration can result in the jamming of particles in regions with a high packing density, making the interface solid-like, albeit only under compression and not tension. However, how this asymmetry in the surfactant properties alters the droplet shape under shear is unknown. Here, we show that shear of particle-stabilized droplets can lead to a remarkable array of shape deformations as the droplets flow through a constrained microchannel. The shear-induced migration of particles on the surface results in the formation of an elastic shell at the back of the droplet, which can wrinkle and invaginate, ultimately leading to a unique core-shell structure. The shapes depend on the Peclet number of the flow, reflecting the balance of shear forces that drive the particles and diffusion that randomizes them. These findings highlight the consequences of the asymmetry in the forces between the particles and provide a unique method to controllably create droplets with a vast array of different shapes.

Performance analysis of natural draft power plant cooling tower: Mathematical modeling of cross-flow type, application in capital cities of Iranian provinces

Cooling towers are heat exchangers that reduce the hot water temperature produced by process equipment through heat and mass transfer between water and air stream. This study investigates the performance of cross-flow cooling towers under various geometrical, physical, and environmental conditions. For this purpose, thermodynamic modeling of the cross-flow cooling tower was conducted, and the governing equations were numerically solved using the finite difference method. Unlike previous studies, the effects of water droplet deformation into an elliptical shape during its fall along the cooling tower were also considered. This deformation, which influences the drag coefficient, Reynolds number of the water droplets, droplet surface area, and its cross-section area, along with the incorporation of buoyancy force in the droplet momentum equation, led to an improvement in the results. Consequently, the maximum computational error in this case was reduced to 1.97 %, compared to the scenario where droplet deformation and buoyancy force were neglected. The change in geometrical parameters of the tower in Tehran and Rasht was investigated, revealing that increasing the outlet radius of the tower from 20 m to 22.5 m decreased the outlet water temperature by 1.21 °C and 0.67 °C and increased the thermal efficiency of the tower by 4.94 % and 2.88 % respectively, while increasing the tower height from 100 m to 120 m, only decreased the outlet water temperature by 0.47 °C and 0.26 °C, and increased the thermal efficiency of the tower by 1.89 % and 1.09 % respectively. Additionally, the cooling tower performance was assessed in the centers of different provinces .of Iran. Results showed that with an initial droplet radius of 1 mm and an inlet water temperature of 50 °C, the maximum and minimum temperature reductions occurred in Shahrekord by 20.16 °C and Bandarabbas by 12.37 °C, respectively.

Influence of constant and alternating electric fields on the deformation and destruction of a liquid droplet

Examining the impact of electromagnetic field, which provides thrust in contemporary rocket engines, is turning into a significant issue. Its resolution is required to guarantee the safety of space flight by enhancing engine performance and lowering fuel consumption. Spacecraft propulsion is achieved by low-thrust rocket engines. The principle of operation for ion colloid engines is the electrostatic acceleration of charged droplets. A static electric field accelerates charged liquid droplets created by electrospraying them in a low-thrust colloid engine. A promising technology in many industries is the active control of droplet motion and deformation with electric field. An electromagnetic field impact on droplet deformation and destruction in a viscous liquid is examined. The effect of electromagnetic field on individual droplets and emulsions is examined in terms of their physical mechanisms. Constant and alternating electric field effects on liquid droplet are represented numerically. The effects of droplet electric capillary number and viscosity ratio on droplet unsteady deformations is explored. The parameters that correspond to the droplet destruction are found. The results obtained have potential applications in enhancing the efficiency of current industrial electric dehydrators and in advancing the development of new electromagnetic field-based demulsification technologies.

Low-Reynolds-number droplet motion in shear flow micro-confined by a rough substrate

A three-dimensional spectral boundary element method has been employed to compute for the dynamics of the droplet motion driven by shear flow near a single solid substrate with a rough surface. The droplet size is comparable with the surface features of the substrate. This is a problem that has barely been explored but with applications in biomedical research and heat management. This work numerically investigated the influences of surface roughness features, such as the roughness amplitude and wavelength, on the droplet deformation and velocities. We observe that a greater amplitude or wavelength leads to larger variations in droplet velocity perpendicular to the substrate. The droplet velocity along the substrate increases when the amplitude is reduced or when the wavelength increases. The effects of capillary number and viscosity ratios have also been studied. The droplet deformation and its velocity increases as we increase the capillary number, while the viscosity ratio shows a non-monotonic influence on the droplet behavior. The predicted droplet behaviors, including deformation, velocities, and trajectories, can provide physical insight, help to understand the droplet behavior in microfluidic devices without a perfectly smooth surface, and contribute in the design and operation of those devices.

The application of optical tweezers in oil-in-water emulsions

Oil-in-water (O/W) emulsions are widely used in industrial production, food science, petrochemicals, and other fields. Quantitative measurement of the interaction between droplets is essential for the in-depth understanding of the stability mechanism of O/W emulsions. Optical tweezers are able to accurately and quantitatively measure the interaction forces between droplets in oil-in-water emulsion systems at the microscopic scale and offer numerous advantages. In this paper, the applications of optical tweezers in oil-in-water emulsion systems are reviewed. Optical tweezer can be used to control the droplet deformation and study the aggregation phenomenon of emulsion droplets. The most important application of optical tweezer for emulsion is to measure the interaction force between emulsion droplets. Some specific examples are given to illustrate the advantages and uniqueness of optical tweezers in measuring droplets interaction forces and the methods to improve the accuracy of interaction force measurement. We summarize the study progress of optical tweezers in measuring the interaction force between droplets in recent years and discuss the challenges and prospects of measuring the interaction force between droplets based on optical tweezers.

ЗАРЯДТАЛҒАН ТАМШЫНЫҢ ОРНЫҚСЫЗДЫҚ УАҚЫТЫНА ТҰТҚЫРЛЫҚТЫҢ ӘСЕРІН ТЕОРИЯЛЫҚ ЗЕРТТЕУ

A nonlinear integral equation describing the time-dependent change of viscosity during spherical deformation of an unstable droplet with specific charge was obtained and its solution was determined. Since the considered phenomenon is nonlinear, it was shown that the characteristic time of instability is determined by the time of ten times increase of the amplitude of the virtual spherical deformation of the unstable droplet from the initial negligible value.

Flux and fouling behavior during constant pressure sterile filtration of nanoemulsions

Nanoemulsions with droplet diameters from 20 to 200 nm have emerged as attractive adjuvants in the development of novel vaccines and as an advanced method of drug delivery for hydrophobic drugs. However, the large size of the nanoemulsion droplets leads to very low capacities during the final sterile filtration step used to ensure sterility of parenteral drug products. The objective of this study was to examine the sterile filtration of a model nanoemulsion made using squalene as the oil and Tween 20 and Span 85 as stabilizing surfactants. Data were obtained with different commercial sterile filters with different morphology and chemistry during constant pressure filtration. In each case, there was essentially no filtration until the transmembrane pressure exceeded a critical value related to the force required to push the deformable nanoemulsion droplets through the membrane pores. The filter capacity increased with increasing pressure, going from 700 g/m2 at 140 kPa to 1300 g/m2 at 280 kPa for a dual layer polyethersulfone sterile filter, with the flux decline well described by the complete pore blockage model. The dual layer asymmetric membranes showed much higher capacities than corresponding single layer filters due to the effectiveness of the upper layer in removing larger nanoemulsion droplets that would otherwise block the pores of the sterile filter. The capacity of the different sterile filters was also well-correlated with the initial filtrate flux, with both of these parameters governed by the pore size distribution and surface chemistry of the filters. These results provide important insights into factors controlling the sterile filtration of highly concentrated nanoemulsions used in the formulation of vaccines and drug products.

Passive Droplet Microfluidic Platform for High-Throughput Screening of Microbial Proteolytic Activity.

Traditional bacterial isolation methods are often costly, have limited throughput, and may not accurately reflect the true microbial community composition. Consequently, identifying rare or slow-growing taxa becomes challenging. Over the past decade, a new approach has been proposed to replace traditional flasks or multiwell plates with ultrahigh-throughput droplet microfluidic screening assays. In this study, we present a novel passive droplet-based method designed for isolating proteolytic microorganisms, which are crucial in various biotechnology industries. Following the encapsulation of single cells in gelatin microgel compartments and their subsequent clonal cultivation, microcultures are passively sorted at high throughput based on the deformability of droplets. Our novel chip design offers a 50-fold improvement in throughput compared to a previously developed deformability-based droplet sorter. This method expands an array of droplet-based microbial enrichment assays and significantly reduces the time and resources required to isolate proteolytic bacteria strains.

Collision dynamics of binary equal-size droplets at high pressures: a focus on stretching separation and reflexive separation

ABSTRACT Stretching separation and reflexive separation are two collision regimes that give rise to satellite droplets, significantly impacting the droplet size distribution. However, the influence of high pressure on these regimes remains unclear. This paper investigates the collision dynamics of binary equal-size droplets under varying ambient pressures using the volume of fluid method and adaptive mesh refinement. The results show that vortices, generated during droplet motion changes or ligament ruptures, facilitate mass transport within the droplet–droplet deformation. Additionally, this paper summarizes four phases of droplet deformation in the separation regimes, which are delayed in stretching separation and advanced in reflexive separation with increasing ambient pressure. Elevated ambient pressure restricts droplet movement, resulting in tougher ligament fractures, smaller satellite droplets, and an expanded coalescence regime boundary. Unlike previous works, this paper incorporates gas kinetic and dissipation energies during droplet collisions at high pressures, revealing that at 7 MPa, the gas dissipation energy is comparable to the liquid dissipation energy and cannot be neglected. To account for these effects, a pressure-dependent formula is integrated into the composite collision model under the Lagrangian framework, offering enhanced predictions of droplet size within the stretching separation regime.

Numerical investigation on the interaction characteristics between the gaseous detonation wave and the water droplet

In this paper, the interaction characteristics between the gaseous detonation and the water droplet are numerically investigated, utilizing a modified compressible two-phase flow model coupling with detailed hydrogen-oxygen chemistry. Firstly, an analysis is conducted on the propagation behaviors of the cellular detonation obstructed by the droplet. It is found that the cellular detonation undergoes reflection, diffraction, local extinction, and re-ignition upon the obstruction, and these behaviors vary with the droplet relative positioning with multi-dimensional structures of the cellular detonation, particularly in terms of the extinction degree caused by the diffraction and the relative positioning of the re-ignition region. Further, the droplet deformation characteristics are detailly analyzed. It has been revealed that the deformation behavior of the shocked droplet under planar detonation is consistent with that under high-speed airflow. However, for the droplet shocked by the cellular detonation, several windward surface pits are induced due to impaction from transverse shocks and direct hitting of the triple-point. The emergence of these pits notably precedes the onset of surface instabilities caused by high-speed airflow erosion. Further investigation has revealed that post-detonation flow, through the entrainment effect of the central pit, progressively penetrates and segregates the droplet into upper and lower segments, and this penetrating effect heavily depends on the droplet relative positioning. Moreover, the side pit, whose presence is significantly determined by whether there is direct impaction of the triple-point on the droplet windward side, is crucial for the deformation around the droplet equator and the subsequent shedding of smaller droplets.

Magnetic field-mediated ferrofluid droplet deformation in extensional flow

Extensional flow is vital in droplet dynamics, influencing their formation, size, stability, and functionality across diverse applications from industrial processes to biomedical technology. Ferrofluid droplets are pivotal in many such applications, where magnetic fields enable non-contact manipulation without undesirable heating effects. However, controlling ferrofluid droplet dynamics in magnetically influenced extensional flows is challenging due to the complex interplay of induced magnetization, intrinsic magnetic properties, and flow kinematics. Here, we present a first-principle-based theory delving into the morphology of a ferrofluid droplet under the combined influence of an external magnetic field and extensional flow. Unlike previous studies, we employ an asymptotic analysis that delves on the shape alterations by considering local magnetization as dependent on magnetic field intensity. Additionally, we develop a numerical model based on phase-field hydrodynamics to establish the practical applicability of the asymptotic solution and to explore large droplet-deformation regimes. The study demonstrates that increasing the magnetic field intensity, the saturation magnetization of the ferrofluid, and the initial magnetic susceptibility each independently improve droplet deformation. Additionally, we found that in a uniform magnetic field, the extensional viscosity of a ferrofluid emulsion is influenced by the strain rate, leading to strain-thickening behavior in the dilute emulsion. Our findings offer new insights into field-assisted manipulation of ferrofluid droplets, emphasizing their potential in applications ranging from process engineering to biomedical technology.