Line Velocity Research Articles

Droplet evaporation on pillar structured surface: A 3D lattice Boltzmann numerical study

In this paper, a three-dimensional symmetric lattice Boltzmann (LB) model is built up to investigate evaporation of a sessile droplet on pillar structured surfaces. Parametric effects on droplet evaporation, including pillar structure size, roughness, temperature and wettability, are studied comprehensively, with emphasis on the variations of contact angle, contact radius and velocity of triple-phase contact line (TPCL) as well as heat and mass fluxes during evaporation. Pillar structures are found to induce the droplet to split into spherical cap part and liquid film part, resulting in an evaporation mode different from that on a plain surface. The extent of pinning-depinning is strongly associated with structures when TPCL retracts between pillars. Increasing surface temperature can accelerate evaporation by breaking the constant contact angle (CCA) mode, and increasing surface roughness accelerates evaporation by decreasing the duration of CCA mode. The majority of heat and mass transfer takes place around TPCL. High wettability can facilitate the evaporation of spherical cap due to the meniscus at liquid–vapor interface in the vicinity of pillar top surface. The substrate heat flux directly affected by structure size is higher in the region where pillars are distributed, and the solid–liquid interfacial heat flux varies with the specific interface location within droplet. The total mass flux primarily depends on the TPCL length determined by the droplet evaporation mode. When the droplet evaporates by partial penetration in the Cassie state, the amount of evaporation at liquid–vapor interface between pillars is greater than that above pillars. This paper provides more details and insights for a deep understanding of droplet evaporation on pillar structured surfaces.

Triladyl® improves the cryopreserved quality and in vivo fertilization potential of Beetal buck (Capra hircus) spermatozoa

This study compared differential concentrations of chicken egg yolk (v/v; T1, 10%; T2, 15%; and T3, 20%) in commercial extender Triladyl® with tris-citric acid based extender (v/v; chicken egg yolk: 20%; C, control) for improving the in vitro quality and in vivo fertilization potential of Beetal buck (Capra hircus) spermatozoa at post–thawing. The mean values of progressive motility (PM, %), rapid velocity (RV, %), average path velocity (VAP, μm sec−1), straight line velocity (VSL, μm sec−1), curvilinear velocity (VCL, μm sec−1), supra-vital plasma membrane integrity (SV−PMI, %), mitochondrial transmembrane potential (MMP, %), and viable with intact acrosome (V−IACR, %) were significantly higher(except significantly lower medium velocity; MV, %)in T1 and T2with than control at all stages. Mean values of straightness (STR – VSL: VAP %) and linearity (LIN – VSL: VCL %) were significantly higher in T1 and T2 than control at PD. In vitro longevity, from 0 to 3 h incubation (37 °C), showed significantly low PM (T1) and RV (T1 and T2) percentage loss than control at PT. A significantly positive Pearson’s correlation was noticed between CASA and SV−PMI, MMP, V−IACR, and DNA integrity (%). Significantly higher in vivo fertilization rates (%) were recorded in T1 (73.53) and T2 (74.19) compared to the C (46.88) and T3 (48.28), respectively. In conclusion, addition of even chicken egg yolk at 10% (v/v) in Triladyl® improves the cryopreserved in vitro and in vivo quality of Beetal buck spermatozoa as compared to tris-citric acid extender with 20% (v/v) egg yolk.

Integrated Guidance-and-Control Design for Three-Dimensional Interception Based on Deep-Reinforcement Learning

This study applies deep-reinforcement-learning algorithms to integrated guidance and control for three-dimensional, high-maneuverability missile-target interception. Dynamic environment, reward functions concerning multi-factors, agents based on the deep-deterministic-policy-gradient algorithm, and action signals with pitch and yaw fins as control commands were constructed in the research, which control the missile in order to intercept targets. Firstly, the missile-interception system includes dynamics such as the inertia of the missile, the aerodynamic parameters, and fin delays. Secondly, to improve the convergence speed and guidance accuracy, a convergence factor for the angular velocity of the target line of sight and deep dual-filter methods were introduced into the design of the reward function. The method proposed in this paper was then compared with traditional proportional navigation. Next, many simulations were carried out on high-maneuverability targets with different initial conditions by randomization. The numerical-simulation results showed that the proposed guidance strategy has higher guidance accuracy and stronger robustness and generalization capability against the aerodynamic parameters.

V838 Mon: A slow waking up of Sleeping Beauty?

Context. V838 Monocerotis is a peculiar binary that underwent an immense stellar explosion in 2002, leaving behind an expanding cool supergiant and a hot B3V companion. Five years after the outburst, the B3V companion disappeared from view, and has not returned to its original state. Aims. We investigate the changes in the light curve and spectral features to explain the behaviour of V838 Mon during the current long-lasting minimum. Methods. A monitoring campaign has been performed over the past 13 years with the Nordic Optical Telescope to obtain optical photometric and spectroscopic data. The datasets are used to analyse the temporal evolution of the spectral features and the spectral energy distribution, and to characterise the object. Results. Our photometric data show a steady brightening in all bands over the past 13 years, which is particularly prominent in the blue. This rise is also reflected in the spectra, showing a gradual relative increase in the continuum flux at shorter wavelengths. In addition, a slow brightening of the Hα emission line starting in 2015 was detected. These changes might imply that the B3V companion is slowly reappearing. During the same time interval, our analysis reveals a considerable change in the observed colours of the object along with a steady decrease in the strength and width of molecular absorption bands in our low-resolution spectra. These changes suggest a rising temperature of the cool supergiant along with a weakening of its wind, most likely combined with a slow recovery of the secondary due to the evaporation of the dust and accretion of the material from the shell in which the hot companion is embedded. From our medium-resolution spectra, we find that the heliocentric radial velocity of the atomic absorption line of Ti I 6556.06 Å has been stable for more than a decade. We propose that Ti I lines are tracing the velocity of the red supergiant in V838 Mon, and do not represent the infalling matter as previously stated.

Phenomenology and kinetics of sessile droplet evaporation on convex contours

In this article we probe experimentally and theoretically the evaporation phenomenology and kinetics of sessile droplets seated over convex hydrophilic and super-hydrophobic (SH) surfaces. To understand the role of convex contours, both cylinders (mono-curvature system) and spheres (two-curvature system) have been explored. The evolution of the droplet shape during evaporation was monitored by optical imaging. The observations reveal improved evaporation rates on convex substrates, and the same tends to increase with increasing curvature. The findings also show that the influence of a two-curvature system (sphere) on the evaporation rate is to a higher extent than that for a mono-curvature system (cylinder). These observations are attributed to the augmented liquid-vapor interfacial area and widened up vapor diffusion domain which renders the liquid-molecules more scope to diffuse in the surrounding environment. The dynamic behavior of the triple line (TL) on convex substrates shows higher receding velocity of the contact line especially on spherical substrates. To visualize the internal flow and understand the effect of substrate convexity on internal advection dynamics, particle image velocimetry (PIV) was carried out. These results show higher strength of circulation velocity inside a droplet evaporating over convex surfaces despite frequent de-pinning of contact line. This behavior can be explicated by the fact than on convex surfaces higher temperature gradient exists along the liquid-vapor interface of the droplet (due to more evaporative cooling, and mapped through infrared thermography), which induces stronger thermal-Marangoni convection, thereby scaling up the circulation velocity. The finding may hold implications towards the design and development of droplet-based thermofluidic devices.

Probing dissipation in spreading drops with granular suspensions

In this paper, we study the spreading of droplets of density-matched granular suspensions on the surface of a solid. Bidispersity of the particle size distribution enriches the conclusions drawn from monodisperse experiments by highlighting key elements of the wetting dynamics. In all cases, the relation between the dynamic contact angle and the velocity of the contact line is similar to that for a simple fluid, despite the complexity introduced by the presence of particles. We extract from this relation an apparent wetting viscosity of the suspensions that differs from that measured in the bulk. Dimensional analysis supported by experimental measurements yields an estimate of the size of the region inside the droplet where the value of the dynamic contact angle depends on a balance of viscous dissipation and capillary stresses. How particle size compares with this viscous cut-off length seems crucial in determining the value of the apparent wetting viscosity. With bimodal blends, the particle size ratio can be used to show the effects of the local structure and volume fraction at the contact line, both impacting the value of the corresponding wetting viscosity.

A generalized scaling theory for spontaneous spreading of Newtonian fluids on solid substrates

HypothesisThere exists a generalized solution for the spontaneous spreading dynamics of droplets taking into account the influence of interfacial tension and gravity. ExperimentsThis work presents a generalized scaling theory for the problem of spontaneous dynamic spreading of Newtonian fluids on a flat substrate using experimental analysis and numerical simulations. More specifically, we first validate and modify a dynamic contact angle model to accurately describe the dependency of contact angle on the contact line velocity, which is generalized by the capillary number. The dynamic contact model is implemented into a two-phase moving mesh computational fluid dynamics (CFD) model, which is validated using experimental results. FindingsWe show that the spreading process is governed by three important parameters: the Bo number, viscous timescale τviscous, and static advancing contact angle, θs. More specifically, there exists a master spreading curve for a specific Bo and θs by scaling the spreading time with the τviscous. Moreover, we developed a correlation for prediction of the equilibrium shape of the droplets as a function of both Bo and θs. The results of this study can be used in a wide range of applications to predict both dynamic and equilibrium shape of droplets, such as in droplet-based additive manufacturing.

Locating Type II-P Supernovae Using the Expanding Photosphere Method. I. Comparing Distances from Different Line Velocities

W present the results of our work testing a version of the Expanding Photosphere Method (EPM) used by Hamuy et al. and Dessart & Hillier to calculate distances to Type II-P supernovae, accounting for the deviations of their luminosities from those of true blackbodies. This method was applied to a sample of supernovae with data sets covering different postexplosion time periods. Different spectral lines in visible wavelengths—Hβ, He i, Fe ii, Sc ii, Na i, and Ba ii—are used to measure the expansion velocity with the goal of determining the species that produces the most reliable distance determination when combined with the blackbody temperature of the effective photosphere. This research suggests that Hβ, Fe ii, and Ba ii lines are most likely to yield accurate distances when combined with blackbody temperature, and provides further evidence of EPM’s effectiveness as an indicator of distance, provided we have a minimum of three data sets covering a broad range of postexplosion phases of the supernova.

Thermocapillary migration of thin droplet on wettability-confined track

The thermocapillary migration of droplets on a solid surface is widely used in daily life and industrial fields. Regulating droplet thermocapillary migration by changing surface wettability has received extensive attention. According to the lubrication theory and slip boundary conditions, we establish a mathematical model of the thermocapillary migration dynamics of a droplet on wettability-confined tracks subjected to a uniform temperature gradient. Combined with the contact line dynamics, a method of determining the velocity of the contact line in a different direction of the three-dimensional droplet is proposed, the simulation is carried out with FreeFEM++. The evolution of droplet migration is examined, and the effects of track width and wettability on the droplet migration dynamics are emphatically investigated. The results show that the main part of the droplet moves from the high-temperature region to the low-temperature region, the trailing edge of the droplet forms a small bulge during the movement, and a thin liquid film is formed between the bulge and the main part of the droplet. The droplet spreading perpendicular to the track direction is inhibited and remains pinned after shrinking to the track edge. Negative correlation between the velocity of the advancing contact line and the track width is observed. The velocity of the advancing line first rapidly and then slowly decrease to a steady state. The squeezing effect caused by the wettability confined perpendicular to the track direction accelerates the thermocapillary migration of the droplet on the track in the initial short time. The enhanced track wettability increases the initial velocity of the receding contact line but has little effect on its stable value. The velocity of the advancing contact line is positively correlated with track wettability. Changing the track width is possibly easier to regulate the thermocapillary migration of a droplet than varying the track wettability.

Dynamic Wetting of Ionic Liquid Drops on Hydrophobic Microstructures.

Ionic liquids (ILs)─salts in a liquid state─play a crucial role in various applications, such as green solvents for chemical synthesis and catalysis, lubricants, especially for micro- and nanoelectromechanical systems, and electrolytes in solar cells. These applications critically rely on unique or tunable bulk properties of ionic liquids, such as viscosity, density, and surface tension. Furthermore, their interactions with different solid surfaces of various roughness and structures may uphold other promising applications, such as combustion, cooling, and coating. However, only a few systematic studies of IL wetting and interactions with solid surfaces exist. Here, we experimentally and theoretically investigate the dynamic wetting and contact angles (CA) of water and three kinds of ionic liquid droplets on hydrophobic microstructures of surface roughness (r = 2.61) and packing fraction (ϕ = 0.47) formed by micropillars arranged in a periodic pattern. The results show that, except for water, higher-viscosity ionic liquids have greater advancing and receding contact angles with increasing contact line velocity. Water drops initially form a gas-trapping, CB wetting state, whereas all three ionic liquid drops are in a Wenzel wetting state, where liquids penetrate and completely wet the microstructures. We find that an existing model comparing the global surface energies between a CB and a Wenzel state agrees well with the observed wetting states. In addition, a molecular dynamic model well predicts the experimental data and is used to explain the observed dynamic wetting for the ILs and superhydrophobic substrate. Our results further show that energy dissipation occurs more significantly in the three-phase contact line region than in the liquid bulk.

The long-term broad-line responsivity in MKN 110

ABSTRACT We examine the long-term history of the optical spectrum of the extremely variable Active Galactic Nucleus (AGN) MKN 110. By combining various archival data with new data, we cover an unprecedented long period of ∼30 yr (1987–2019). We find that the He ii λ4686 emission line changes by a factor of forty and varies more strongly than the optical continuum. Following Ferland et al., we take He ii λ4686 as a proxy for the FUV continuum and compare the flux of several other line species against it. This comparison reveals a clear pattern, whereby lines respond close to linearly at low FUV fluxes, and saturate at high FUV fluxes. The saturation level of the response appears to depend on the excitation energy of the line species. In addition to this global pattern, we note changes among observational epochs, indicating a structural evolution in the broad line region (BLR). The line profiles in our spectra show an offset between the narrow and broad components of the He ii λ4686 and H β lines. This offset shows a significant negative correlation with the FUV flux and a positive correlation with the line velocity width. Our analysis reveals a complex BLR response to a changing continuum. The clear presence of a non-responsive component of the broad lines indicates the existence of multiple contributions to the line emission. We find there are several kinematic models of the BLR and inner regions of the AGN that match our data.

Sperm parameters in the Great Dane: Influence of age on semen quality

Not all sires have sperm suitable for chilled or frozen storage, and success in artificial insemination (AI) varies highly among individual dogs and breeds. Fertilizing potential is further complicated as sperm quality declines with the aging process. Due to the rapidity of aging and senescence in large breed dogs, associated health and fertility changes may be observed over a shorter period, though this period remains undefined for any breed. Working with a population of purebred Great Danes (GD), our aims were (1) to characterize the distribution of a series of sperm parameters, (2) to distinguish sources of variation in sperm quality within this rapidly aging breed, and (3) to identify changes in sperm quality that may accompany aging. Ejaculates collected from young, middle-aged, and senior Great Dane dogs (n = 50) were evaluated for semen volume, total sperm number and viability, and reactive oxygen species (ROS), in addition to sperm morphology and kinematic parameters. Total testicular volume was also determined using ultrasonography. Testicular volume was not a predictor of sperm production in the GD, however, significant differences between coat colors were identified. Age was negatively associated with total motility, progressive motility, and amplitude of lateral head displacement (ALH) (p < .05). We identified significant relationships between GD male age and TM, PM, and immotility with −9.9%, −9.0%, and +8.3% change per year of age, respectively, which support the anecdotal reports of decline of the fertility with the advance of age in this breed. Sperm of younger GD dogs aged 12 ≤ x < 24 months had significantly higher TM, PM, ALH, and nonlinear motility (p < .05) than older dogs (x ≥ 48 months). High ROS levels were positively associated with TM and PM, average pathway distance (DAP) and straight line distance (DSL), average pathway velocity (VAP), straight line velocity (VSL), and the presence of hairpin tails (p < .05). While age and ROS have significant influences on sperm parameters in the GD, the influence of selection for breed specific phenotypes could help explain the functional significance of the diversity among GD males.

Properties of Type Iax Supernova 2019muj in the Late Phase: Existence, Nature, and Origin of the Iron-rich Dense Core

Type Iax supernovae (SNe Iax) form a class of peculiar SNe Ia, whose early phase spectra share main spectral line identifications with canonical SNe Ia but with higher ionization and much lower line velocities. Their late-time behaviors deviate from usual SNe Ia in many respects; SNe Iax continue showing photospheric spectra over several 100 days and the luminosity decline is very slow. In this work, we study the late-time spectra of SN Iax 2019muj, including a newly presented spectrum at ∼500 days. The spectrum is still dominated by allowed transitions but with a lower ionization state, with possible detection of [O i]λλ6300, 6363. By comprehensively examining the spectral formation processes of allowed transitions (Fe ii, Fe i, and the Ca ii near-IR triplet) and forbidden transitions ([Ca ii]λλ7292, 7324 and [O i]), we quantitatively constrain the nature of the innermost region and find that it is distinct from the outer ejecta; the mass of the innermost component is ∼0.03 M ⊙ dominated by Fe (which can initially be 56Ni), expanding with a velocity of ∼760 km s−1. We argue that the nature of the inner component is explained by the failed/weak white-dwarf thermonuclear explosion scenario. We suggest that a fraction of the 56Ni-rich materials initially confined in (the envelope of) the bound remnant can later be ejected by the energy input through the 56Ni/Co/Fe decay, forming the second unbound ejecta component which manifests itself as the inner dense component seen in the late phase.

Application of dislocation-based constitutive model into research of dynamic mechanical behavior under shock loading

To understand the plastic deformation mechanism of an FCC metal (pure aluminum) under shock loading and describe its dynamic mechanical behavior accurately, a multiscale constitutive model based on the dislocation substructure is developed, which comprehensively considers the controlling mechanisms of dislocation motion and dislocation evolution. Then, the model is extended to the loading of strong shock waves by incorporating the homogeneous nucleated dislocation within the constitutive framework. The model parameters are successfully determined by the normal plate impact experiments with different thicknesses of specimens. Additionally, shock front perturbation decay experiments are performed using a line velocity interferometer system for any reflector, where the modulated surface of the specimen is subjected to a laser-driven loading. Then, the model is applied to reproduce the perturbation decay of shock fronts in experiments. During the post-process of simulated results, the method based on the pressure gradient is used to determine the amplitude and the location of distributed shock fronts. The extended model shows promise as an effective method to figure out the role of strength (shear response) on the evolution of perturbation amplitude.

First-Principles Fermi Acceleration in Magnetized Turbulence.

This Letter provides a concrete implementation of Fermi's model of particle acceleration in magnetohydrodynamic (MHD) turbulence, connecting the rate of energization to the gradients of the velocity of magnetic field lines, which it characterizes within a multifractal picture of turbulence intermittency. It then derives a transport equation in momentum space for the distribution function. This description is shown to be substantiated by a large-scale numerical simulation of strong MHD turbulence. The present general framework can be used to model particle acceleration in a variety of environments.

Scanning Drop Friction Force Microscopy.

Wetting imperfections are omnipresent on surfaces. They cause contact angle hysteresis and determine the wetting dynamics. Still, existing techniques (e.g., contact angle goniometry) are not sufficient to localize inhomogeneities and image wetting variations. We overcome these limitations through scanning drop friction force microscopy (sDoFFI). In sDoFFI, a 15 μL drop of Milli-Q water is raster-scanned over a surface. The friction force (lateral adhesion force) acting on the moving contact line is plotted against the drop position. Using sDoFFI, we obtained 2D wetting maps of the samples having sizes in the order of several square centimeters. We mapped areas with distinct wetting properties such as those present on a natural surface (e.g., a rose petal), a technically relevant superhydrophobic surface (e.g., Glaco paint), and an in-house prepared model of inhomogeneous surfaces featuring defined areas with low and high contact angle hysteresis. sDoFFI detects features that are smaller than 0.5 mm in size. Furthermore, we quantified the sliding behavior of drops across the boundary separating areas with different contact angles on the model sample. The sliding of a drop across this transition line follows a characteristic stick-slip motion. We use the variation in force signals, advancing and receding contact line velocities, and advancing and receding contact angles to identify zones of stick and slip. When scanning the drop from low to high contact angle hysteresis, the drop undergoes a stick-slip-stick-slip motion at the interline. Sliding from high to low contact angle hysteresis is characterized by the slip-stick-slip motion. The sDoFFI is a new tool for 2D characterization of wetting properties, which is applicable to laboratory-based samples but also characterizes biological and commercial surfaces.

Material removal mechanism and microstructure fabrication of GDP during micro-milling

Glow discharge polymer (GDP) material is essential for target ball fabrication in inertial confinement fusion applications. Fine microstructures (∼several tens-hundreds of micros) machining on the GDP surface is required for directing the high-power laser. The machinability and material removal mechanism of the GDP are critical to achieve high surface quality, remaining an unsolved challenge. This study investigated cutting mechanisms of the GDP based on feed per tooth and inclination angle in micro ball-end milling. Chip formation modes and machined surface morphologies as well as their generation mechanism were studied. Three types of chips (i.e., chip clusters, bulk/node chips, banded chips) were formed when the forming force of compression shifts to shear. Thermal effect and plastic flow promote a smooth surface under the squeezing effect of the tool cutting edge. The different ratios of feed rate to tool line velocity caused the micro pits and feed marks on the machined surface with the viscoelasticity of polymer material. By analyzing the cutting force, specific cutting force and machined surface roughness, together with the chip modes and surface morphologies, a transition of cutting modes from ploughing to ploughing-shearing coexistence and then to shearing were revealed. Finally, micro-dimpled structures were machined for validating the influence of the reveled material removal mechanism for fabrication of microstructures. The presented findings are of great significance for the application of micro-cutting processes in future engineering fabrication of microstructures on the GDP target ball.

Cold Roll Forming Process Design for Complex Stainless-Steel Section Based on COPRA and Orthogonal Experiment.

Cold roll forming can fabricate products with complex profiles, and its parameter optimization can achieve high quality and improved precision of products. In this paper, taking the side shield as a typical product, the cold roll forming of a complex section of stainless steel SUS301L-ST is analyzed, establishing a 3D finite element model by using the professional roll forming software COPRA. We propose a floating roll device for complex sections with asymmetry and large depth. We use an orthogonal experiment to obtain the inter-distance between rolls, friction coefficients, the diameter increments, and line velocities to investigate the effects on the maximum longitudinal strain of the edge. Results show that the diameter increment has the greatest influence on the maximum strain, and its increases can reduce the strain. The inter-distance value needs a suitable range. A small value is not conducive to the release of elastic deformation, while a large value will cause unexpected displacement and increase the cost. The friction coefficient increases; although it helps to reduce the strain, it will cause scratches and other defects on the stainless steel. The increase in velocity increases the strain. We derive the optimal parameters for the complex section, providing a theoretical basis for practical production.

Sperm tendency to agglutinate in motile bundles in relation to sperm competition and fertility duration in chickens

A unique sperm behavior was observed in Egyptian chickens. Sperm showed a tendency to agglutinate forming motile thread-like bundles. Sperm agglutination behavior, kinematics, and some morphometric measures were studied in relation to sperm competition and fertility duration in Sharkasi and Dandarawi chickens. Sperm tendency to agglutinate was assessed by examining sperm morphology using scanning electron microscopy, Acridine orange-stained semen smears using fluorescence microscopy, and recording videos of sperm under phase contrast microscope. Sperm velocity and morphometric measures were evaluated using image-J software. To assess sperm competition, Sharkasi and Dandarawi hens were artificially inseminated by semen pools possessing equal number of Sharaksi and Dandarawi sperm. Artificial insemination was repeated ten times. The eggs obtained were incubated, and the hatchlings were discriminated as descending from Sharkasi or Dandarawi fathers according to their phenotype. To assess the fertility duration, Sharkasi and Dandarawi hens were inseminated by semen collected from roosters of the same strain. Eggs were collected for a period of 28 days post-insemination and incubated. Sharkasi spermatozoa showed higher tendency to agglutinate forming longer and thicker motile bundles. No significant differences were observed in sperm curvilinear and straight line velocity and in sperm morphometric measures between Sharkasi and Dandarawi chickens. Sharkasi roosters fathered 81.6% and 67.7% of the hatchlings produced by Sharkasi and Dandarawi mothers, respectively. The fertility period in Sharkasi and Dandarawi was 22 and 14 days, respectively. We suggest that the differences seen in sperm competitiveness and fertility duration can be attributed to sperm agglutination behavior.

Contact line dynamics of a water drop spreading over a textured surface in the electrowetting-on-dielectric configuration.

Modeling the electrowetting process of a liquid droplet placed on a hydrophobic surface in an ambient environment has several challenges over and above those of basic spreading [F. Mugele, Soft Matter 5, 3377 (2009)10.1039/b904493k]. At an external voltage below the value that causes contact angle saturation, transient spreading is augmented by contact angle reduction defined by the Young-Lippmann equation. In addition, the macroscopic equilibrium contact angle and, therefore, the spreading rate could be altered by the surface hysteresis. Beyond the saturation point, spreading reveals additional features of higher complexity [Q. Vo and T. Tran, J. Fluid Mech. 925, A19 (2021)10.1017/jfm.2021.677]. These details have been examined from experiments as well as numerical simulation in the present work. Below the saturation point, the contact angle model of Dwivedi etal. [Phys. Rev. Fluids 7, 034002 (2022)10.1103/PhysRevFluids.7.034002] with the correction related to the electric field is seen to be applicable. Beyond saturation, the experimentally determined instantaneous contact angle distribution shows two distinct functionalities with respect to the contact line velocity. The first prevails from the onset of spreading until the spreading factor attains a peak value. The second trend is initiated with the retraction of the contact line. Except for differences in parametric values, the form of the contact angle model remains unchanged. Simulations in the postsaturation regime are shown to match experimental data in terms of the transient spreading factor, drop shapes, and the instantaneous contact angle. The role of the ground wire is found to be important and the three-phase contact line formed on it has been included in simulations. Spreading dynamics of the droplet have also been studied when the ground wire is kept at a distance of 40 μm from the apex of the drop. Simulations as well as experiments, show the propagation of a capillary wave between the ground wire and the three-phase contact line. For spreading over an uncoated polydimethylsiloxane (PDMS) surface, the contact line is trapped at local pinning sites, leading to additional distortions in the instantaneous shapes acquired by the interface.