Fluid Kinematics Research Articles

Capillary wave-assisted collapse of non-Newtonian droplets

Understanding the peripheral capillary wave propagation during droplet impact is crucial for comprehending the physics of wetting onset and droplet fragmentation. Although Newtonian droplets have been extensively studied, we show how capillary waves deform non-Newtonian droplets in such a way that rheological features, such as the critical concentrations for the overlap (c*) and entangled polymer molecules (c**), may be directly obtained from the deformation history. Determining these critical concentrations is essential as they mark transitions in the rheological behavior of aqueous polymeric solutions, influencing viscosity, elasticity, and associated fluid dynamics. We have also compared capillary waves among Newtonian, shear-thinning, and Boger fluid droplets and found that although the fluid kinematics appear to be purely biaxial extensional flow, the infinite-shear properties of the droplets dominate the physics of capillary wave formation and propagation.

Theoretical and Experimental Investigation of Material Removal Rate in Magnetorheological Shear Thickening Polishing of Ti–6Al–4V Alloy

Abstract Magnetorheological shear thickening polishing (MRSTP) is a novel hybrid polishing method that combines the magnetorheological effect and the shear thickening effect. It has great potential for ultra-precision machining of complex surfaces. However, the absence of a correlation between material removal and the rheological properties of the polishing media has posed difficulties for further improvements in polishing efficiency and quality in MRSTP. In this work, a material removal model for MRSTP was established based on the principles of magneto-hydrodynamics, non-Newtonian fluid kinematics, and microscopic contact mechanics. This model combines the material removal model for a single abrasive particle with a statistical model of active grits. When comparing the experimental and theoretical results, it became evident that the developed material removal model can accurately predict the material removal depth of the workpiece under different processing parameters such as rotational speed of the rotary table and magnetic field strength. The average prediction error was found to be less than 5.0%. Furthermore, the analysis of the rheological behavior and fluid dynamic pressure of the polishing media reveals the coupling effects between the magnetic, stress, and flow fields. This provides theoretical guidance for the actual processing of MRSTP. Finally, the maximum material removal rate of 3.3 μm/h was achieved on the cylindrical surface of the Ti–6Al–4V workpiece using the MRSTP method. These results demonstrate that the MRSTP method holds great potential in the field of ultra-precision machining of difficult-to-machine materials.

Greenwater due to plunging breaking wave impingement on a deck structure. Part 1: Experimental investigation on fluid kinematics

This study experimentally investigates the kinematics of greenwater resulting from plunging breaking wave impacts on a deck structure. Two impingement scenarios, characterized by different breaking points, were considered. The ensemble-averaged flow fields were obtained by applying both PIV (particle image velocimetry) and BIV (bubble image velocimetry) techniques to 50 repeated tests. The study examines flow patterns, velocity fields, and derived quantities from velocity data to identify differences in flow behaviors, variations in velocity magnitude, and potential distribution of peak impact pressures. The presented results provide useful information and indication for assessing concentrated loadings and enhancing our understanding of hydrodynamic behaviors. Additionally, the validity of applying Ritter dam break solutions to describe the horizontal velocity distribution of greenwater flows is examined, and prediction equations based on self-similar horizontal velocity distribution are derived.

Estimation of Wind Speed Based on Schlieren Machine Vision System Inspired by Greenhouse Top Vent.

Greenhouse ventilation has always been an important concern for agricultural workers. This paper aims to introduce a low-cost wind speed estimating method based on SURF (Speeded Up Robust Feature) feature matching and the schlieren technique for airflow mixing with large temperature differences and density differences like conditions on the vent of the greenhouse. The fluid motion is directly described by the pixel displacement through the fluid kinematics analysis. Combining the algorithm with the corresponding image morphology analysis and SURF feature matching algorithm, the schlieren image with feature points is used to match the changes in air flow images in adjacent frames to estimate the velocity from pixel change. Through experiments, this method is suitable for the speed estimation of turbulent or disturbed fluid images. When the supply air speed remains constant, the method in this article obtains 760 sets of effective feature matching point groups from 150 frames of video, and approximately 500 sets of effective feature matching point groups are within 0.1 difference of the theoretical dimensionless speed. Under the supply conditions of high-frequency wind speed changes and compared with the digital signal of fan speed and data from wind speed sensors, the trend of wind speed changes is basically in line with the actual changes. The estimation error of wind speed is basically within 10%, except when the wind speed supply suddenly stops or the wind speed is 0 m/s. This method involves the ability to estimate the wind speed of air mixing with different densities, but further research is still needed in terms of statistical methods and experimental equipment.

Selection of vortex ripple dimensions in sinusoidal oscillatory flows. Part 1. Ripple dimensions and fluid kinematics

Subaqueous vortex ripples in equilibrium are characterized by their unique geometry and dimensions. Motivated by the recent direct numerical simulation study of oscillatory turbulent flow over a wavy bottom by Önder & Yuan (J. Fluid Mech., vol. 858, 2019, pp. 264–314), the objective of this study is to further investigate the fluid dynamical controls that determine the distinctive equilibrium dimensions of vortex ripples. We use direct numerical simulations to investigate the differences in flow kinetics between sinusoidal oscillatory flow over equilibrium and out-of-equilibrium vortex ripples. In comparison with the equilibrium case, the spanwise coherent vortices, the averaged bottom shear stress on overlying flow and the shear stress distribution on the ripple surface are identified as the key fluid dynamical controls on equilibrium dimensions. Based on these controls, we propose mechanisms in the selection of vortex ripple dimensions. We observe that the flow adjusts in such a way that the interaction between overlying flow and vortex ripples tends to generate the strongest coherent vortices while the ripple surface (or overlying flow) experiences the smallest shear stress averaged over ripple wavelength during the selection process. Through a triple decomposition of the flow, the component of the ripple-induced fluctuation is found to dictate these fluid dynamical controls, which implies that this component plays an important role in the evolution of vortex ripples.

Design analysis and modeling of a floating wave power plant in the coastal zone using the module of computational fluid dynamics

The features of modeling a floating wave power plant (FWPP) in the computational fluid dynamics module are considered. A description of the computational fluid dynamics module is given and its application is shown in optimizing the design of FWPP. The stages of modeling, the order of construction, the necessary initial and boundary conditions, the goals and results of calculations are given. Keywords: floating wave power plant, hydraulic structure, computational fluid dynamics, modeling, power generation, kinematic parameters, internal and surface waves, energy. noreas@mail.ru

Experimental investigation on fluid kinematics and impact pressure of flat plate impacts on pure and aerated water

This study aims to demonstrate the applications of existing techniques for water entry problems in quantifying the multiphase flow regions, and to perform an experimental investigation on pure and aerated water entry of a flat plate. Measured pressure, velocity field, and local aeration level were utilized to examine the fluid kinematics and dynamics. Maximum water speeds were measured up to 1.59C and 1.74C for pure and aerated water entry, respectively, with C being the impact speed. Three stages of pressure evolution were identified. The intensity of the oscillation after the shock load was found negatively correlated with aeration level. Impact coefficient up to 27.64 was observed at the center of the plate bottom for pure water entry. The pressure impulse of the shock load was found less dependent on aeration level. For the shock load in aerated water entry, the correlation of peak pressure and rise time of yields distributions similar to those for breaking wave impacts. At all measurement points, an inversely proportional trend appears in the correlation between estimated peak forces and local aeration levels.

Evaluation on the Performance of Airflow Distribution Device of Pneumatic Seeder for Rapeseed through CFD Simulations

The seeding performance of a pneumatic seed-metering equipment for rapeseed has a significant bearing on the sowing effect. When the negative pressure falls abruptly, the pneumatic system experiences a significant loss of negative pressure. This will prevent rapeseed from being entirely absorbed by the seed plate, resulting in inconsistent seeding quantities along each row. In this study, CFD simulations were used to analyze the airflow field affecting the airflow transmission of an airflow distribution device. The essential structural characteristics of a conical cylinder conical-arranged kind of airflow distribution device were found, and the causes of negative pressure loss were analyzed from the standpoint of fluid kinematics. The optimal structural type of airflow distribution device was determined using fluid simulation. In addition, an orthogonal examination of the ideal type’s essential structural characteristics was conducted to minimize negative pressure loss during airflow transmission. Then, the influence of the negative pressure loss rate of the airflow distribution device on the variation coefficient of seeding quantity in each row of the seed-metering device was investigated using a bench test involving three factors: seed plate rotational speed, working negative pressure, and structure type. It was discovered that three parameters have highly substantial impacts on the negative pressure loss rate and the variation coefficient of seeding quantity in each row, and that the negative pressure loss rate correlates positively with the variation coefficient of the seeding quantity in each row. When negative pressure fell to 500 Pa, the negative pressure loss rate of the optimal structure type and the variation coefficient of seeding amount in each row of the seed-metering device fell by 6.25% and 3.45%, respectively. Field experiments reveal that the negative pressure loss rate of an airflow distribution device was below 20% and that the variation coefficient of seeding amount in each row of seed-metering devices was below 3.5%. The results can be used to analyze the construction of the pneumatic system and enhance the performance of the seed-metering equipment.

High-fidelity modelling of moored marine structures: multi-component simulations and fluid-mooring coupling

High-fidelity viscous computational fluid dynamics (CFD) models coupled to dynamic mooring models is becoming an established tool for marine wave-body-mooring (WBM) interaction problems. The CFD and the mooring solvers most often communicate by exchanging positions and mooring forces at the mooring fairleads. Mooring components such as submerged buoys and clump weights are usually not resolved in the CFD model, but are treated as Morison-type bodies. This paper presents two recent developments in high-fidelity WBM modelling: (i) a one-way fluid-mooring coupling that samples the CFD fluid kinematics to approximate drag and inertia forces in the mooring model; and (ii) support for inter-moored multibody simulations that can resolve fluid dynamics on a mooring component level. The developments are made in the high-order discontinuous Galerkin mooring solver MoodyCore, and in the two-phase incompressible Navier–Stokes finite volume solver OpenFOAM. The fluid-mooring coupling is verified with experimental tests of a mooring cable in steady current. It is also used to model the response of the slack-moored DeepCwind FOWT exposed to regular waves. Minor effects of fluid-mooring coupling were noted, as expected since this a mild wave case. The inter-mooring development is demonstrated on a point-absorbing WEC moored with a hybrid mooring system, fully resolved in CFD-MoodyCore. The WEC (including a quasi-linear PTO) and the submerged buoys are resolved in CFD, while the mooring dynamics include inter-mooring effects and the one-way sampling of the flow. The combined wave-body-mooring model is judged to be very complete and to cover most of the relevant effects for marine WBM problems.

Kinematic Properties of a Twisted Double Planetary Chaotic Mixer: A Three-Dimensional Numerical Investigation.

In this study, a numerical investigation based on the CFD method is carried out to study the unsteady laminar flow of Newtonian fluid with a high viscosity in a three-dimensional simulation of a twisted double planetary mixer, which is composed of two agitating rods inside a moving tank. The considered stirring protocol is a “Continuous sine squared motion” by using the dynamic mesh model and user-defined functions (UDFs)to define the velocity profiles. The chaotic advection is obtained in our active mixers by the temporal modulation of rotational velocities of the moving walls in order to enhance the mixing of the fluid for a low Reynolds number and a high Peclet number. For this goal, we applied the Poincaré section and Lyapunov exponent as reliable mathematic tools for checking mixing quality by tracking a number of massless particles inside the fluid domain. Additionally, we investigated the development of fluid kinematics proprieties, such as vorticity, helicity, strain rate and elongation rate, at various time periods in order to view the impact of temporal modulation on the flow properties. The results of the mentioned simulation showed that it is possible to obtain a chaotic advection after a relatively short time, which can deeply enhance mixing fluid efficiency.

Understanding Key Factors during Dod Inkjet Printing Towards Precise Fabrication of Micro Energy Systems

There is an ever-increasing need for micro energy systems that can power miniature, unmanned, or remotely-located devices. Drop-on-Demand (DOD) inkjet fabrication is uniquely positioned for this demand due to its low-cost processing with microscale resolution, high throughput, reproducibility, and ease in shape design. This study seeks to capitalize on the advantages of DOD inkjet printing for application to manufacturing micro energy conversion/storage systems, by defining the fundamental jet kinematics and key factors underpinning the inkjet printing process.The ink used in this study was a dilute colloidal ink suspension composed of a common solid oxide fuel cell (SOFC) cathode material [La0.6Sr0.4Fe0.8Co0.2O3 (LSFC)] and organic solvent α-terpineol. The results were evaluated systematically in terms os final deposition quality, resolution, and microstructure. Favorable fluid kinematics were identified that attained uniform, well-shaped, circular 0-D dots about 0.1 µm thick and 60 µm in diameter. To increases the microfeature thickness and x/y plane dimensions , multiple and/or sequential ink passes were employed. For printing 1-D lines, the spacing between droplets was imperative to fabricating quality micro features. Using appropriate conditions, 1-D lines with x/y dimensions < 100 µm and controllable z axis dimensions at 0.1 µm per printing pass with dense, open or networked microstructures were demonstrated. 2-D planes at the dimensions as small as 100 µm by 100 µm were also achieved with smooth surface and continuous intra-planar ceramic coverage. In the course of post-processing the inkjetted cathodes, it was observed that the submicron cathode films printed at optimal conditions, after being sintered at controlled conditions, were uniform, smooth and free of cracks or delamination.This research demonstrated through fundamental understanding and control of the inkjet fabrication process, cathode features can be printed with controlled dimension and quality towards producing a functioning micro SOFC operable at low temperatures. The knowledge gained from this research will be appliable to other micro energy conversion and storage systems.

ROMSPath v1.0: offline particle tracking for the Regional Ocean Modeling System (ROMS)

Abstract. Offline particle tracking (OPT) is a widely used tool for the analysis of data in oceanographic research. Given the output of a hydrodynamic model, OPT can provide answers to a wide variety of research questions involving fluid kinematics, zooplankton transport, the dispersion of pollutants, and the fate of chemical tracers, among others. In this paper, we introduce ROMSPath, an OPT model designed to complement the Regional Ocean Modeling System (ROMS). Based on the Lagrangian TRANSport (LTRANS) model (North et al., 2008), ROMSPath is written in Fortran 90 and provides advancements in functionality and efficiency compared to LTRANS. First, ROMSPath calculates particle trajectories using the ROMS native grid, which provides advantages in interpolation, masking, and boundary interaction while improving accuracy. Second, ROMSPath enables simulated particles to pass between nested ROMS grids, which is an increasingly popular scheme to simulate the ocean over multiple scales. Third, the ROMSPath vertical turbulence module enables the turbulent (diffusion) time step and advection time step to be specified separately, adding flexibility and improving computational efficiency. Lastly, ROMSPath includes new infrastructure which enables inputting of auxiliary parameters for added functionality. In particular, Stokes drift can be input and added to particle advection. Here we describe the details of these updates and performance improvements.

Liutex based new fluid kinematics

Liutex based new fluid kinematics

Genesis of Antibiotic Resistance (AR) XC (90): Turbulence Modeling(TM) of Hemodynamics in Simplified Severe Sepsis Protocol‐2 (SSSP‐2)‐NCT01663701: Mechanism(s) of Jarisch Herxheimer Reaction (JHR) induced CCP ‐ CEP‐ A Neuropsychiatric Basis

Clinical Focus: An effort is made to delineate the underlying hemodynamic alteration in the usual care group registered with 5 patients @ 100% ihm; vs the sepsis protocol cohort with 11 patients @ 90.05% ihm with a median hospital stay of 5 days (Ref: Fig 3. Risk of ihm by subgroup for patients treated with the sepsis protocol vs usual care; p1239) NCT01663701, (PMID: 28973227). The goal is to explore whether there is any temporal link between neuropsychiatric indices and SSSP‐2. Hypothesis: The AR clPr causing STD, with CCI, Tx with antibiotics (PMID: 31331661; NBK557820; PMID: 32491752), released toxins exacerbating the vortices formation in fluid bolus induced fluid volume expansion by Flow‐Induced Vibration (FIV) (Oscillating flow) (VIV). Here, we present a possible mechanism(s) for the FIV(VIV) evoked irreversible rupture of cerebral vessels eliciting ihm. (PMID: 28077740 PMCID: PMC5239707; PMID: 9846580; PMID: 9733392). Geometry: Part I: RBC, Platelets, WBC: p47‐56; Part II: blood velocity, and function, Table 2.1; 2,2; 2.3; p63; ISBN 9780128024089; Governing Equations: Part A: Strouhal Number= St = fwD/V, where D is the characteristic length of Leucocyte, platelets, red blood cells (Bluff bodies @LPE –ZoO), fs=Vortex Shedding frequency, V=flow velocity; Part B: Drag Coefficient: Cd= 2Fd / ρu2A,where Fdis drag force‐velocity in the direction of flow, ρ =density of the fluid (hematocrit), u =flow speed, A=surface area of the vortices; Part C: Drag Equation = Fd=1/2 ρu2CdA, where Cdis the function of Re (Mach number); Part D: CD, https://www.grc.nasa.gov/www/k‐12/airplane/shaped.html; CFD Simulations: https://youtu.be/ahohd8ceGR4 (VS); Correlation neuropsychiatry indices &amp; SSSP‐2: Based on our analysis, it is suggested that, the antibiotics administered in NCT01663701 likely induced JHR (PMID: 25174641) in which fluid bolus (SSSP‐2), eddied vortices (ZoO/bluff bodies) of different dimensions (CD)(Ref CD, Drag of 2‐D bodies: Fig:7.2; 7.3; ISBN: 9781260446555), may have induced vibrations at high flow velocities by tip‐vortices at ~ 1/3 of KSF, (whereas the critical flow velocity for lock‐in, ~3X critical velocity of KSF (Ref Fig 2.1; 2.2;2,3, ISBN 9780081013182). Impediments to determine the precise geometry of vortices due in part to an unknown rate of AB induced adducts, remains of AR clPr, its role in LPE activation, degranulation and aggregate formation (vortices@ZoO/bluff bodies). Though a complete PMHx, Dx, DDx, HPI, CCI, &amp; SOAP of the SSSP‐2 patient cohort is unavailable, of a plethora of vortices, cylindrical vortices are a possibility. When such vortices encounter oscillating flow as in Fig 2.3, p 34; the velocity of oscillation leads to variation in CD and fluid inertia forces traversing downstream of flow. As a result, a superposed in‐flow &amp; transverse bending vibration in‐line could predominate as t=0, t= τ/12, (τ =wave period) rupturing the pre‐capillary vessels Fig 1, PMID: 34055944 to CCP to CEP. Efforts are underway to determine fluid kinematics (Keulegan‐Carpenter Eq) FIV/VIV in SSSP2 (LRC, TMR, NASA https://turbmodels.larc.nasa.gov/) .PD funds from SWTJC to Subburaj Kannan

The shape of wave-packets in a three-layer hydrodynamic system

The article is devoted to the problem of wave-packet propagation in a three - layer hydrodynamic system "layer with a hard bottom - layer - layer with a cover stratified by density. The current research on selected topics is reviewed. The mathematical formulation of the problem is given in dimensionless form and contains the equations of fluid motion, kinematic and dynamic conditions on the contact surfaces, as well as the boundary conditions on the lid and on the bottom. Using the method of multiscale developments, the first three approximations of the studied problem are obtained, of which the first two are given in the article, because the third approximation has a cumbersome analytical form. The solutions of the first approximation and the variance relation are presented. The evolution equations of the circumferential wave-packets on the contact surfaces are derived in the form of the nonlinear Schrodinger equation on the basis of the variance relation and the conditions for the solvability of the second and third approximations. A partial solution of the nonlinear Schrodinger equation is obtained after the transition to a system moving with group velocity. For the first and second approximations, the formulas for the deviations of the contact surfaces are derived, taking into account the solution of the nonlinear Schrodinger equation. The conditions under which the shape of wave-packets on the upper and lower contact surfaces changes are derived. The regions of familiarity of the coefficients for the second harmonics on the upper and lower contact surfaces for both frequency pairs, which are the roots of the variance relation, are presented and analyzed. Also, for both frequency pairs, different cases of superimposition of maxima and minima of the first and second harmonics, in which there is an asymmetry in the shape of wave packets, are graphically illustrated and analyzed. All results are illustrated graphically. Analytical transformations, calculations and graphical representation of results were performed using a package of symbolic calculations and computer algebra Maple.

New fluid kinematics

Fluid kinematics describes the fluid motion without consideration of any force. Classical fluid kinematics adopts Helmholtz velocity decomposition, which is equivalent to Cauchy-Stokes (CS) velocity gradient tensor decomposition. CS decomposes the velocity gradient tensor into a strain-rate (symmetric) tensor and a vorticity (anti-symmetric) tensor. However, several questions arise: (1) since vorticity cannot represent fluid rotation, the vorticity tensor is a mixture of vorticity shear and rigid rotation, (2) since the strain-rate tensor cannot represent fluid shear, the strain-rate tensor is a mixture of stretching and shear, (3) the stretching and shear in the CS decomposition are dependent on the selection of coordinate system and are therefore not Galilean invariant. On the other hand, Liutex is a new physical quantity to represent the rigid fluid rotation and a principal coordinate system can be set up based on Liutex. A principal decomposition of the velocity gradient tensor, or the rotation-stretching-shear decomposition, can be easily carried out in the principal coordinate system with a clear physical meaning, which represents the rigid rotation, stretching (compression) and shear (symmetric and anti-symmetric shear). In the principal decomposition, all elements in three sub-tensors are Galilean invariant and, therefore, the principal decomposition is unique, Galilean invariant and independent of coordinate system. The principal decomposition is then transformed back to the original xyz coordinate system. The Liutex-based principal decomposition creates the new fluid kinematics which is ready for building up new fluid dynamics. Since fluid kinematics is the foundation of the fluid dynamics, the new fluid kinematics could replace the classical fluid kinematics, Helmholtz or CS decomposition, and open a new gate to develop new fluid dynamics especially for vortex science and turbulence research.

Properties of the pressure field in highly nonlinear free surface flows with critical jet

In this note we examine fluid violent kinematics in a plunging breaker. The fluid motion is computed in the frame of the potential flow theory. The fluid kinematics is basically generated by forcing the motion of a rectangular tank, starting from rest. When a sufficient level of energy is injected in the fluid, the free surface has highly nonlinear behavior, here a plunging breaker. In the vicinity of the main tip crest, a sharp corner (cusp) appears along the surface of the barrel. The appearance of this critical jet is described and discussed in terms of the spatial and temporal variations of the pressure field. In the present case a local pressure maximum is captured that follows a continuous decreasing pressure gradient in a region of positive Gaussian curvature of the pressure. It is also shown that, at the free surface before the appearance of the critical jet, there is a strong correlation between the change of sign of the Gaussian curvature of the pressure on the one hand and the radius of curvature of the free surface profile on the other hand.

Three-Dimensional Numerical Simulations and Antifouling Mechanism of Microorganisms on Microstructured Surfaces

As marine biofouling seriously affects the development and utilization of oceans, the antifouling technology of microstructured surface has become a research hotspot due to its green and environmentally friendly advantages. In the present research, the motion models of microorganisms on the surfaces of five rectangular micropits, in co-current and counter-current flow direction, were established. Dynamic mesh technology was used to simulate the movements of microorganisms with different radii in the near-wall area, and the fluid kinematics and shear stress distributions in different-sized micropits were compared. Furthermore, moving microorganisms were included in the three-dimensional microstructure model to achieve the real situation of biofouling. Simulation results revealed that the vortex flow velocity in the micropits increased with the increase of the inlet flow velocity and the existence of the vortex flow effectively reduced the formation of conditioning layers in the micropits. In the downstream and countercurrent directions, the average shear stresses on the wall decreased with the increase of the micropit depth and width, and the shear stress on the inner wall of the Mp1 micropit (a patterned surface arranged with cubes of 2 µm × 2 µm × 2 µm) was found to be the largest. A low shear stress region with a low flow velocity was formed around microorganisms in the process of approaching the microstructured surface. The shear stress gradient of micro-ridge steps increased with the approach of microorganisms, indicating that microridge edges had a better effect on reducing microbial attachment.

Deep-learning-based liquid extraction algorithm for particle image velocimetry in two-phase flow experiments of an object entering water

Particle image velocimetry (PIV) enables the study of instantaneous fluid kinematics through flow visualization, which promotes the study of an object entering a liquid surface. However, even with PIV, the accurate extraction of the liquid phase region remains elusive due to the unsteady hydrodynamic forces involved. Therefore, we present a deep-learning network based on U-Net to solve the problems. The network, named MRes-Att-Unet, combines the mechanisms of residual connectivity and attention, which is proven to be effective in medical image segmentation. Considering the use of a training of network in supervised learning, we created a corresponding dataset based on the PIV experiment of an object entering water in two-phase flow and tested the images of an object entering water in an isolated wave crushing experiment. The results showed that the MRes-Att-UNet improved the segmentation accuracy of the gas–liquid boundaries, with especially enhanced results in a wide range of laser scattering, fuzzy bubbles, splash, and other complex interferences. Moreover, a WIDIM method is used to process the segmented and original images, and the results show that a deep learning method is feasible for segmenting PIV images and can effectively reduce the error vector of two-phase flow boundary.

On the statistical properties of surface elevation, velocities and accelerations in multi-directional irregular water waves

Abstract