Component Of Gravity Research Articles

Effects of inclined state and rolling motion on gas–liquid effective interfacial area in a rotating packed bed

Confined space and floating environment present high challenges for gas–liquid separation and purification processes on offshore platforms. Rotating packed beds (RPBs) have shown great potential in onshore application, but its performance under offshore conditions remains unclear. This study first investigates the effective interfacial area (ae) within an RPB under inclined and rolling conditions by using the CO2 chemisorption method. The inclined state and rolling motion significantly affect ae, which is determined jointly by the secondary axial distribution and gas flow direction. The adverse effects occur at low rotational speed (N) due to the liquid collection driven by the gravity component, and increasing N was found to effectively against the collection and improve ae. Furthermore, ae under different motion periods and operating conditions were also investigated, and its relative rates of change and fluctuation can reach up to 17.4% and 10.7%, respectively. These results suggest that RPBs are somewhat resistant to marine conditions, providing the basis for offshore applications.

Computation and Analysis of Geopotential Number in São Paulo, Brazil

In recent decades, important steps have been taken to implement the physical concepts of Geodesy in practice, con- cerning height systems. Despite the difficulties involving gravity field modeling, with the establishment of conventions, standards, and computation strategies, the realization of the International Height Reference System (IHRS) is well underway. For a global system, there are constraints for some countries, especially for those with sparse gravity data, mountain regions, and vast areas. In terms of methodology, the computation can be performed directly using the Global Geopotential Models (GGM), recovering existing geoid models, or determining pointwise the gravity potential using integral formulas. In general, the regional gravity modeling is given by numerical integration or least-squares collocation and more recently adopting the spherical radial basis functions. The first approach allows determining the earth’s gravity component at a specific point and adjusting the integral formula according to the gravity coverage. Since so far there is no common sense about the best methodology, computation strategies are been analyzed. In this con- text, the paper aims to contribute to IHRF, computing the geopotential number in the scope of IHRF, using numerical integration to solve the Geodetic Boundary Value Problem and an existing recent quasi-geoid model in four stations in São Paulo state, Brazil. The first approach was performed considering two cases: a radius of 210 km and 110 km of gravimetric data coverage and the Global Geopotential Model GOCO05S truncated at 100 and 200, respectively. The results between solutions have shown a maximum difference of 94 cm, and a minimum difference of 10 cm.

Multiscalar-Metric Gravity: Cosmological Constant Screening and Emergence of Massive-Graviton Dark Components of the Universe

In the multiscalar-metric frameworks, the issues of the vacuum energy/cosmological constant (CC) screening due to Weyl-scale enhancement of the Diff gauge symmetry, along with emergence of the massive dark gravity components through the gravitational Higgs mechanism are considered. A generic dark gravity model is developed, with two extreme versions of the model of particular interest based on general relativity (GR) and its classically equivalent Weyl transverse alternative, being compared and argued to be, generally, inequivalent. The so constructed spontaneously broken Weyl Transverse Relativity (WTR) is proposed as a viable beyond-GR effective field theory of gravity, with screening of the Lagrangian CC, superseded by the induced one, and emergence of the massive tensor and scalar gravitons as dark gravity components. A basic concept with the spontaneously broken Diff gauge symmetry/relativity—in particular, WTR vs. GR—as a principle source of the emergent dark gravity components of the Universe is put forward.

Research on steering-tilting characteristics of an active tilting three-wheeled vehicle

Active tilting narrow vehicles can prevent rollover and improve riding stability through active tilting technology during steering, but it is difficult to obtain the turning radius and solve the optimal tilting angle. In this paper, based on the active tilting three-wheeled vehicle (ATTWV), the geometric analysis method of steering wheel’s alignment was proposed and used to calculate the specific formula of turning radius during steering and tilting, and the effect of tilting on the turning radius was studied. Based on the steering and tilting mathematical model of force equilibrium state, the ideal tilting angle was solved and the S-shaped curve steering test verification was carried out with the prototype vehicle. The results show that the lateral acceleration of the vehicle fluctuates within ±0.16 g during steering, realizing the equilibrium between the component of gravity and centrifugal force. The average error between the actual tilting angle and the calculated ideal tilting angle is 1.18°. Based on steering and tilting mathematical model of the rollover critical state of the ATTWV, the safe turning speed under the specific tilting angle can be solved, and the value range of the tilting strength coefficient can be obtained, which provides not only a reference for the control of ATTWVs but also a theoretical basis for the research on accurate self-driving control of the active tilting narrow vehicles in the future.

Hydrological influence on the variation of the terrestrial gravity field in Manaus, Amazonas, Brazil

The influence of groundwater on the hydrological cycle has been studied at large-scale across the Amazon Basin, one of the largest freshwater reservoirs in the world. Considering this Basin's importance in the global hydrological cycle, local studies also are critical. Here, we focus on the local hydrological cycle in Manaus, at the center of the Amazon Basin. We observed the variability of local gravity, fluvial height, soil moisture, precipitation, evapotranspiration and groundwater in the rainy (December–May) and dry (June–November) seasons, during drought (2016) and flood (2017) years. In general, in the beginning of the rainy season, soil moisture is instantaneously influenced by the first precipitation, increasing gravity. After, the soil becomes saturated and the variation in soil moisture achieves maximum values, which are sustained until the end of rainy season. After soil saturation by infiltration, the groundwater starts to be fed by percolation and the water table starts to rise. Thus, variation in local gravity reflects mainly variations in groundwater level. After the dry season starts, the soil loses moisture (soil moisture values decrease), while the gravity signal maintains high values, representing the sustained behavior of the groundwater. Modeling the vertical gravity component influenced by soil moisture and by groundwater results, respectively, in 49.63 nm/s2 and 314.70 nm/s2. In comparison with the gravity measurement of 368.02 nm/s2, we confirm that the groundwater is the main contributor to the gravity signal. We also find a strong correlation between fluvial height and the gravity signal, but demonstrate with 3D modeling that the Negro River height variation does not directly influence the gravity signal. Instead, we explain the similarity in fluvial height and the gravity signal by the connection between fluvial height and groundwater, and the correlation between groundwater and gravity variations.

Structural Mapping Inferred from Gravity Data to Image the Upper Lithospheric Structures and its Hydrocarbon Implication from Gwandu Formation NW, Nigeria

Presently a digitized composite satellite gravity data covering the Gwandu formation in Sokoto Basin were acquired and processed with a view to interpret the Bouguer anomalies as well to equally image the upper lithospheric structures beneath the Study area and its environs. The research work was aim to study the structural settings of crustal movement in the Gwandu formation. A least-square fitting polynomial surface of a third-degree order was applied in separating regional and residual gravity components from the Bouguer anomaly. The attributed low gravity sedimentary infill from the residual anomalies were tectonically trends NE -to- SW about the vicinities of Tambuwal, Goronyo, Gada and Argungu, Kolmalo and about Yauri, Koko and Jega, Kamba as well as Bagudo. Data enhancement techniques such as first vertical derivative, total horizontal derivative (THDR), analytic signal, spectral depth analysis, and the standard Euler deconvolution (SED) were applied to enhance deep-seated structures. Results from the Spectral Analysis revealed that the average thickness of the sediments varies from 1.679 km to 4.181 km, outsized enough for hydrocarbon prospect. The derivative maps revealed parallel to sub-parallel trending NW –to- SE, E -to- W fracture zones within the sedimentary infill underlying the study area, coinciding with the cretaceous zones. Hence, the identified lineaments (faults or lithologic contacts) and structures in the area can be attributed to the tectonic setting of the area and probable migratory routes for hydrocarbon migration. More detailed ground gravity and seismic studies may lead to discoveries of structural or stratigraphic traps.

Development of a Lightweight Inertial Gravimeter for Use on Board an Autonomous Underwater Vehicle: Measurement Principle, System Design and Sea Trial Mission

The purpose of this paper is to present the design, development and testing of an innovative instrument called GraviMob, which allows performing dynamic measurements of underwater gravity anomalies. After recalling the interest in underwater gravimetry, we describe the system, the core of which consists of triads of accelerometers rigidly attached to an Autonomous Underwater Vehicle (AUV). The article also presents the mathematical methods for estimating the east, north and vertical components of the local gravity vector. An unscented Kalman filter, integrating AUV position and orientation data, performs estimation of gravity in a frame adapted to its interpretation. To assess its performance, GraviMob was tested in the Mediterranean Sea during the year 2016. A comparison of the surface gravimetric signal previously acquired by the French Navy indicates that the maximum discrepancy between the vertical gravity component and its reference is below 4 mGal. Components of the vertical deflection calculated from GraviMob’s measurements were compared with those calculated from recent gravity field models. While a remarkable agreement was found on the north component, there remains a discrepancy (7 arcsec) on the east component which can be largely reduced by refining the estimation of the orientation of GraviMob’s sensitive axes in the AUV.

Study on the Main Controlling Factors and Formation Mechanism of Motion States of Bottom Hole Assembly in Slightly Deviated Wells

Abstract With the further development of deep oil and gas resources, the deep and ultra-deep wells are used widely, which make lateral vibration of bottom hole assembly (BHA) more violent. Lateral vibration greatly restricts the service efficiency and life of downhole devices. To study the main controlling factors and formation mechanism of lateral motion states in slightly deviated wells, the numerical simulation and indoor experiment were conducted. A drillstring dynamics model with three-dimensional beam elements was built, which combined the advantage of the finite element method and the beam-column theory. The simulation and experiment were carried out to analyze the motion states and motion laws under different drilling coefficients. Four kinds of conventional motion states were classified, and the physical characteristics, forming conditions, and identification methods were given. Four main controlling factors of motion states were summarized, and the formation mechanism was discussed through the principle of least energy consumption and least work consumption. The researches show that the numerical and experimental results are in good agreement. Meanwhile, well inclination, rotational speed, and friction coefficient have significant effects on motion states. The states contain forward whirl, random motion, and backward whirl in vertical wells, and circular arc swing in slightly deviated wells. Moreover, radial component of gravity promotes the formation of circular arc swing, centrifugal force promotes forward whirl before drillstring contacts wellbore and promotes backward whirl after that, tangential friction promotes backward whirl, and internal friction promotes forward whirl. Finally, the paper holds that BHA in vertical wells should operate in the motion state with least output power of the system and also operate in the motion state with least input power of external force during steady motion. The study can lay a theoretical foundation for predicting, identifying, and controlling motion states in drilling field to reduce vibration and improve drilling efficiency.

Quantum gravity corrections to the matter dynamics in the presence of a reference fluid

We analyze the effect induced on standard quantum field theory (in a functional approach) by quantum gravity corrections to a pure classical background. In the framework of the Kucha\ifmmode \check{r}\else \v{r}\fi{} and Torre proposal for a gravity-matter theory constrained to a Gaussian reference frame, materialized as a fluid in the system evolution, we consider a Born-Oppenheimer separation of the system, regarding the gravity degrees of freedom as the slow varying component and the matter plus the Gaussian fluid as fast quantum coordinates. The slow gravity component obeys the Wheeler-DeWitt equation, and we consider a Wentzel-Kramer-Brillouin expansion of its quantum dynamics via a Planckian parameter. The main issue of the proposed scenario is that, on one hand, we recover a modified quantum field theory in the presence of a Hermitian Hamiltonian (not affected by nonunitarity as in other approaches) and, on the other hand, we get the Gaussian fluid as a physical clock for such an amended quantum theory (verifying the correct energy conditions). We also show its equivalence with the kinematical action method, used in a previous work, in the homogeneous setting. Then, we implement the proposed paradigm to describe the dynamics of a homogeneous free massless scalar field, living on an isotropic universe, in the presence of a cosmological constant. We completely solve the dynamics up to the first order correction in the Planckian parameter to the standard quantum field theory. We determine the explicit form of the modified scalar field wave function, due to quantum features of the cosmic scale factor evolution. Phenomenological considerations and discussions are provided.

Analysis of metal transfer and weld forming characteristics in triple-wire gas indirect arc welding

Triple-wire gas indirect arc welding (TW-GIA) has the advantages of low heat input and high deposition rate. However, the simultaneous melting of triple wires makes the metal transfer mode complicated. The unknown of the metal transfer mode restricts the development of this technology. In this paper, high-speed camera systems and electrical signal acquisition sensors were used to explore the TW-GIA metal transfer mode. The static force model and the arc conductive channel model were used to discuss the droplet force and energy conversion characteristics, respectively. Results showed that the TW-GIA metal transfer modes can be divided into the following: short-circuit transfer (SCT), main wire projected transfer + side wire globular transfer (PGT), main wire streaming transfer + side wire projected transfer (SPT), and main wire streaming transfer + side wire streaming transfer (SST). Moreover, the process parameter ranges corresponding to the four modes were summarized. Due to the stable arc and the uniform metal transfer process, SPT and SST can form desirable weld seam. The gravity and z-axis components of electromagnetic force are the main forces that promote metal transfer. The x-axis and y-axis components of the electromagnetic force deviate the metal transfer path from the arc coverage. Due to the change of arc conductive channel, the energy transferred from TW-GIA to the base metal is less than that of gas metal arc welding, showing the advantages of small welding deformation, narrow heat-affected zone, and grain refinement.

Auto-Tuning parameters of motion cueing algorithms for high performance driving simulator based on Kuka Robocoaster.

Driving simulators have been utilized to test and evaluate products and services for a long time. Their complexity and price range from extremely simple low-cost simulators with a fixed base to very complex high-end and pricey six-degree-of-freedom simulators with the XY table. The recent novel technique that uses an industrial robot - KUKA Robocoaster - as an interactive motion simulator platform, allowing for a highly flexible workspace as well as significantly lower prices due to mass production of the fundamental mechanics. In the constrained workspace of driving simulators, motion cueing algorithms (MCAs) are commonly employed to merge the tilt gravity and translational acceleration components for simulating the linear acceleration in the real vehicle. However, there is a few MCAs developed for the motion platform, almost MCAs were implemented for the standard six-degree-of-freedom simulators in the Cartesian coordinate. The classical MCA in the cylindrical coordinate (ClCy) MCA was first developed for the novel motion platform to take advantage of enormous rotational motion to simulate lateral acceleration while compensating for the bothersome longitudinal acceleration (due to centrifugal acceleration appearing in the rotational motion) with a proper pitch tilted angle. The process of tuning MCAs for the novel motion platform is time-consuming due to both trial and error method and the disturbing motion cues generated by rotational motion, thus it needs the involvement of experts. Although there are several auto-tuning approaches for classical, optimal, and model-predictive control MCA based on fuzzy control theory or genetic optimization method, the methods were purely applied for Cartersian coordinate without taking the bothersome longitudinal acceleration into account. Therefore, this paper firstly presents the process of integrating MCAs in the novel motion platform utilizing rotational motion for simulating lateral acceleration. For the case, besides the ClCy algorithm, the classical algorithm developed for the standart six-degree-of-freedom simulators was a sample implementation due to its popular and familiar characteristics. Secondly, the proposal of the use of the mean-variance mapping optimization (MVMO) for auto-tuning parameters of the two algorithms for reducing both rotational false cues in roll and pitch channel, and longitudinal acceleration as well as washout effect. The simulation results prove that 1) The classical and other MCAs can be applied in the novel motion platform with the proposed motion conversion; 2) both algorithms with auto-tuned parameters have high performance in exploiting effectively the workspace of the motion platform, producing no false cues of angular velocity, conpensating the disturbed longitudinal acceleration, and pulling the motion platform to the initial position after the simulation task; 3) The auto-tuning method is so transparent that can manipulates the specific simulated quantities according to the tuning goals.

Einstein’s dream to unify all forces finally materializes: a revived de Broglie’s pilot-wave theory with novel solutions

Starting from Louis de Broglie’s pilot wave-theory, this paper unifies gravity and quantum mechanics under a single mathematical field theory for all forces in Nature. Two families of potentials coexist as mathematical solutions for the homogeneous Klein-Gordon equation which is the same homogeneous classical wave equation: (a) Neo-Laplacian local time-independent background potentials, and (b) Novel time-distance entangled Q(q) potentials which are isomorph to distance-time-velocity transformations based on any of the competing relativistic theories (Lorentz, Poincaré or Einstein), or on the pre-relativistic Galilean invariant Doppler equations. This remarkable property makes present theory compatible with all previous empirical evidence, including experiments conventionally interpreted as supporting Einstein’s special relativity. We report explicit closed solutions for potentials solving the one-dimensional and three-dimensional classical wave equations, and describe in detail how to calculate time-independent neo-Laplacian background forces and relativistically isomorph time-dependent entangled forces. The scale of the problem appears as a required parameter, thus making our theory applicable to all scales of Nature from quarks to cosmos. A usually overlooked neo-Laplacian logarithmic potential predicts the observed high values of non-Keplerian tangential speeds at the galactic scale. At the human scale, calculations relative to hurricanes and tornadoes may be facilitated by the closed form of our unified forces. A novel torsion component of gravity automatically appears from our new solutions.

The Advantage Analysis of 3-D Inversion of Airborne Gravity Gradiometry Data With Larger Sampling Interval

Airborne gravity gradiometry is an effective tool for its high efficiency and sensitivity to the interesting buried targets, which has been increasingly introduced in mineral and petroleum exploration. When compared to gravimetry, full tensor gradient (FTG) measurements provide higher resolution and signal-to-noise ratio. In this article, we build and test models with different sampling intervals and compare the performances of individual components or their combinations in minimum structure inversion to evaluate the benefits of FTG combinations. As part of a theoretical study, the singular value spectrum (SVS) and depth-resolution plot (DRP) are examined to determine how much information and resolution different datasets provide in the underdetermined inverse problem. The synthetic examples show that integrating more components in inversion improves the resolution of the recovered model, and the inversion result of gravity or individual component cannot accurately restore the distribution of anomalous bodies. With the increasing sampling interval, joint inversion of FTG data still provides enough information corresponding to the source density distribution, and the limit survey interval is tested through models. In addition, we use a real survey over the Vinton dome as a case study and discover that <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V_{\mathrm {zz}}$ </tex-math></inline-formula> component fails to reconstruct the caprock model at coarse line spacing, whereas FTG combinations recover the acceptable geometry flawlessly. It also reflects the benefit of FTG combinations for inversion processing, which reduces the interference of measured noise on inversion results and allows for longer sampling intervals during the survey, effectively lowering the cost of an airborne survey and improving exploration efficiency

Ekstraksi minyak atsiri rimpang lengkuas merah (Alpinia purpurata, K.Schum.) metode destilasi uap dan air

Galangal is one of Indonesia's spice plants and the rhizome contains chemical components, such as essential oils so that it can be used for various purposes, including medicinal, antimicrobial, cosmetic,abd antifungal. The essential oil content of red galangal rhizome is 0.3-1% depending on the quality of the rhizome. The process of extracting essential oils can be done by steam-water distillation. This study aims to determine the effect of temperature and drying time as a preliminary treatment before distillation. The study was designed using a Randomized Block Design with 2 factors: the first is the drying temperature (50oC; 60oC; 70oC), the second factor is the drying time (2; 4; 6 hours). The analysis was carried out yield, refractive index, specific gravity, color, and chemical components. The material used was red galangal rhizome which was approximately 1 year old. Steam and water distillation method was used for oil extraction for 6 hours. The results showed that the best treatment was the control treatment (without drying) with a yield of 0.076%, refractive index 1.4773%, specific gravity 0.8952 (g/ml), color L 23.365, color a* (-)0.995 , and color b* yellowish (+)3.78. Tthe GC-MS, 37 chemical components were detected, of which 6 main components were found with the highest area value, 1.8-Cineole 27.347%; (Z)-beta-Farnesene 11.641%; 2-Beta-Pinene 8.700%; Phenol, 4-(2-propenyl)-acetate (CAS) 6.369%; 3-Cyclohexen-1-ol, 4-methyl-1-(1-methylethyl)-(CAS) 4.305%; and cis-Ocimene 4.009%. The drying reduces the essential oil yield of galangal rhizome.

Research on the peak prediction and intelligent computing of reversal error for the tilt feed system installed on the precision machine tools

To effectively predict the peak of reversal error of tilt feed system and reduce reversal error caused by friction and gravity components, a peak prediction method of reversal error for tilt feed system on the precision NC machine tool is proposed. According to the load, tilt angle, motion trajectory, maximum static friction torque and relevant dynamic characteristic information, the peak prediction formula of the reversal error for the tilt feed system is established by mathematical derivation based on the kinematics, dynamics and torque balance during the process of reversal. Thus, the peak of reversal error for the tilt feed system can be obtained. The experimental results show that this method can achieve a good prediction effect, and can predict the peak of reversal error before the machining. It provides a theoretical basis for the reversal error suppression.

Retracted: True Gravity in Atmospheric Ekman Layer Dynamics

AbstractTrue gravity is a three‐dimensional vector field, g(λ, φ, z) = igλ + jgφ + kgz, with (λ, φ, z) the (longitude, latitude, height) and (i, j, k) the corresponding unit vectors. The longitudinal‐latitudinal component of the true gravity, gh = igλ+jgφ, is neglected completely in meteorology through using the standard gravity (−g0k, g0 = 9.81 m/s2) or the effective gravity [−g(φ)K]. Here, k (or K) is normal to the Earth spherical (or ellipsoidal) surface. Such simplification of g(λ, φ, z) has never been challenged. This study uses the classical atmospheric Ekman layer dynamics as an example to illustrate the importance of gh. The standard gravity (−g0k) is replaced by the true gravity g in the classical atmospheric Ekman layer equation with a constant eddy viscosity (K) and a height‐dependent‐only density ρ(z) represented by an e‐folding stratification. New formulas for the Ekman spiral and Ekman pumping are obtained. The second derivative of the gravity disturbance (T), , causes the Ekman pumping in addition to the geostrophic vorticity (). With from the EIGEN‐6C4 static gravity model, and calculated from July sea level pressure (p) data from the Comprehensive Ocean‐Atmosphere Data Set, the global mean strength of the Ekman pumping over the world oceans is 3.69 cm s−1 due to gh, which is much larger than 0.33 cm s−1 due to the geostrophic vorticity. It implies the urgency to use the true gravity g(λ, φ, z) into atmospheric GCM and weather forecast although the results are obtained from specific density field and gravity model.

Automated Vehicle Sideslip Angle Estimation Considering Signal Measurement Characteristic

Vehicle slip angle (VSA) estimation is of paramount importance for connected automated vehicle dynamic control, especially in critical lateral driving scenarios. In this paper, a novel kinematic-model-based VSA estimation method is proposed by fusing information from a global navigation satellite system (GNSS) and an inertial measurement unit (IMU). First, to reject the gravity components induced by the vehicle roll and pitch, a vehicle attitude angle observer based on the square-root cubature Kalman filter (SCKF) is designed to estimate the roll and pitch. A novel feedback mechanism based on the vehicle intrinsic information (the steering angle and wheel speed) for the pitch and roll is designed. Then, the integration of the reverse smoothing and grey prediction is adopted to compensate for the cumulative velocity errors during the relatively low sampling interval of the GNSS. Moreover, the GNSS signal delay has been addressed by an estimation-prediction integrated framework. Finally, the results confirm that the proposed method can estimate the VSA under both the slalom and double lane change (DLC) scenarios.

Immiscible capillary flows in non-uniform channels

We consider the release of preferentially wetting fluid in a laterally extensive V-shaped channel initially filled with a second fluid, presenting solutions for the initial exchange flow and the late time spreading of the wetting fluid along the narrow part of the channel. We also show that, if there is a buoyancy force acting in the cross-channel direction, the early time exchange flow depends on the Bond number, and the intermediate time slumping flow may initially be dominated by buoyancy, but at long times becomes controlled by capillarity. Where there is an along-channel component of gravity we show that the flow spreads out downslope, with capillarity controlling the structure of the nose. We then consider the case where the channel is connected to a reservoir of wetting fluid at constant pressure. We show that, depending on this pressure, either a zero flux exchange flow develops, or a net inflow through the whole width of the channel develops, as in the classical Washburn, Lucas, Bell and Cameron capillary imbibition flow. We show these flows are analogous to the classical model for one-dimensional capillary driven flows in porous media, with the current width in the channel corresponding to the saturation in the pore space.

Anti-freezing characteristics of water droplet impinging the superhydrophobic surface: An experimental and predictive study

Water freezing has a significant and non-negligible influence on the aircraft, power transmission lines and operational efficiency of industrial facilities. Therefore, it is of great value and meaning to deeply understand the dynamic behaviors of water droplet impacting the supercooled superhydrophobic surface. In this work, effects of impact velocity, surface temperature and inclined angle on the impinging droplet dynamics are visually investigated. The machine learning model is first proposed to predict the rebound height and temperature limit of fully rebound. The results demonstrate that a larger impact velocity shifts the temperature limit of completely rebound to a higher surface temperature. However, it has little effect on the spreading time and contact time. As the temperature further decreases, portion of droplet is pinned on the substrate instead of fully rebound and the volume of residual droplet increases. As the inclined angle increases, both contact time and rebound height decreases. Due to driven by the tangential component of gravity, width of droplet before detachment increases while the stretched length decreases. The optimal temperature limit of fully rebound is −35 °C with the inclined angle of 30° and We = 19, showing a significant improvement compared to the temperature limit on a horizontal surface.

Two-layer fluid flows on inclined surfaces

Abstract