Viscid Fluid Research Articles

A self-consistent unified solid-multiphase flow shock model under complex thermodynamic states: For the application of mass-loaded single-turn coils

Single-turn coil (STC) is a destructive pulsed magnet aiming at 100–300 T magnetic field. Mass-loading is the method to increase STC magnetic field. In this study, a unified solid-multiphase flow model is proposed to solve the shock contact problem between the conductor and mass-loading material. This model gives the approach to equate the solid to viscid fluid and equate the melted material to solid and derives the constitutive model for the conductor under non-adiabatic state. Especially, the method to calculate non-adiabatic modulus is investigated. The results show that the equivalent viscosity of solid decreases as the strain rate rises. Moreover, the equivalent shear modulus of the melted solid increases as the strain rate rises, and considering this equivalent shear modulus rather than setting it to zero improves the simulation convergence significantly. This model can provide not only theoretical support for the optimal design of destructive pulse magnets but also methods for theoretical modeling of other types of electromagnetic explosion and shock contact experiments under non-adiabatic condition.

Mathematical modeling of creeping electromagnetohydrodynamic peristaltic propulsion in an annular gap between sinusoidally deforming permeable and impermeable curved tubes

The present work investigates the creeping peristaltic propulsion of viscid fluid in an annular gap between sinusoidally deforming permeable and impermeable curved tubes of similar shape under the influence of an externally imposed electric and magnetic field. In this model, the outer tube with a permeable wall surface is supposed to satisfy the Saffman slip condition. The flow equations are simplified by the estimation of a large wavelength in comparison with the radius of the external tube. An analytical solution for the axial velocity is obtained in the computational software MATHEMATICA. Graphical analyses are conducted to explore the variations in wall shear stress, velocity, pressure rise, frictional force, and stream function with respect to different emergent parameters, providing insight into the underlying physics of the flow phenomena. An investigation of the effects of the Hartmann number and electric field strength on the flow through a gap between deformable tubes with curved structures has important implications for a variety of engineering applications, including mechanical and biomedical engineering. The streamlines are plotted to discuss fluid trapping and visualize the flow pattern of the viscid fluid inside the curved annular domain. A comparative analysis of fluid transport induced by sinusoidal, triangular, trapezoidal, and square wave shapes is encountered with the help of streamlined contour diagrams. The comparison of pressure gradients in three different models is also discussed to gain insight due to fluid–structure interaction. A gap in the body of recently published literature is filled by the results discussed in this paper.

Hydrodynamization in hybrid Bjorken flow attractors

Hybrid fluid models, consisting of two sectors with more weakly and more strongly self-interacting degrees of freedom coupled consistently as in the semi-holographic framework, have been shown to exhibit an attractor surface for Bjorken flow. Retaining only the simple viscid fluid descriptions of both sectors, we find that, on the attractor surface, the hydrodynamization times of both subsectors decrease with increasing total energy density at the respective point of hydrodynamization following a conformal scaling, reach their minimum values, and subsequently rise rapidly. The minimum values are obtained when the respective energy densities are of the order of the inverse of the dimensionful inter-system coupling. Restricting to attractor curves which can be matched to glasma models at a time set by the saturation scale for both p-p and Pb-Pb collisions, we find that the more weakly coupled sector hydrodynamizes much later, and the strongly coupled sector hydrodynamizes earlier in p-p collisions, since the total energy densities at the respective hydrodynamization times of these sectors fall inside and outside of the conformal window. This holds true also for phenomenologically relevant solutions that are significantly away from the attractor surface at the time we match to glasma models.

Efficacy of individualized homoeopathic medicine in wrist ganglion: an evidence based case series

AIM - The aim of the study was to evaluate the efficacy of Individualized Homoeopathic medicines in the treatment of dorsal wrist ganglion. OBJECTIVES- Through four evidence-based cases treated with individualized homoeopathic medicines. BACKGROUND- Ganglions are a small cystic tumor containing viscid fluid and are non- malignant growths that usually forms near the joints and tendons of the hand and wrist. They are harmless and non- cancerous growth, mostly asymptomatic. Pain, tenderness, annoyance with cosmetic appearance associated with some cases. Though homoeopathic literature enlists many medicines for wrist ganglion, there is paucity of evidence based published studies. MATERIALS AND METHODS- The patients presented with the complaints of firm to hard swelling at the dorsum of hand. After meticulous case taking, analysis and evaluation of the symptoms followed by Repertorization of the characteristics, the similimum was selected. A single, simple medicine with minimum dose was administered in each case followed by placebo. During entire period of treatment RESULT- Four cases were treated with Phosphorus 200, Calcarea carbonica 1M, Phosphorus 1M and Sulphur 200 respectively. Single dose of medicines was administered as per cardinal principles of homoeopathy and waited for 3 months. Striking improvement in symptomatology was noted after the course of treatment. CONCLUSIONS- Homoeopathic medicines selected on the basis of strict individualization showed promising result in all four cases. Patients reported reduction of symptoms as well as general well being following the treatment. Further studies with sound methodology is suggested to evaluate the efficacy of larger spectrum of homoeopathic medicines in the treatment of wrist ganglion.

Mixed convection in an insulated rectangular enclosure with two obstacles subject to various configurations using multi-relaxation-time lattice Boltzmann method

Mix convection heat transfer is studied in a rectangular lid-driven cavity comprising two obstacles. One of the obstacles is isothermally heated and the other is isothermally cooled. The mass flow and transfer are simulated, taking regular, incompressible, Newtonian, and viscid fluid using Numerical techniques. The fluid follows the Boussinesq approximation. The effect of pertinent parameters like Richardson number (Ri = 0.01, 0.1, 1, 5, 10, 100), Grashof number (), and Prandtl number (Pr = 0.71, 1, 7) is studied. Two aspect ratios of the lid-driven cavity are taken to study the fluid behavior. The effect of centric and eccentric locations of the heated blockages and the effect of different sizes of the obstruction on the fluid flow and thermal transportation are reported. and models of MRT-LBM are implemented for the simulation of flow and heat transfer regimes respectively. Also, Local and Average Nusselt numbers along the walls of a heated obstacle for different dimensionless parameters are calculated. The contour plots for the flow's horizontal and vertical velocity profiles are also discussed. The validation of our result is also checked by the grid independence test. The convergence of against different grid sizes shows that our code is valid.

EHD stability of a viscid fluid cylinder surrounding by viscous/inviscid gas with fluid-particle mixture in permeable media

The article is concerned with Electrohydrodynamics (EHD) instability of an incompressible dielectric viscous fluid in a vertical cylinder that surrounds a dielectric viscous/inviscid gas. The incompressible packing has microscopic fine dust particles of a consistent size. An unchanged tangential electric field influences the system which is saturated in porous media. Given their importance in the stability picture, the fundamental equations that regulate the particle mixture are constructed. The linear stability approach is employed to analyze the system. The motivation for tackling this problem lies in the growing interest in a variety of practical physics and engineering disciplines. The profiles of velocity fields and pressure are evaluated by the conventional normalized approach. A transcendental dispersion relationship connects the rate of growth and the wave number of the wave propagation. The procedure produces several numbers of non-dimensional characteristics of the problem at hand. Appropriate findings have been yielded that match the existing results in the available literature.

Hydrodynamics study of dolphin's self-yaw motion realized by spanwise flexibility of caudal fin

The hydrodynamic performance of the virtual underwater vehicle under self-yaw is investigated numerically in this paper, we aim to explore the fluid laws behind this plane motion achieved by the bionic flexibility, especially the spanwise flexibility of the caudal fin. The kinematics of the chordwise flexible body and the spanwise flexible caudal fin are explored through dynamic mesh technology and user-defined functions (UDF). The 3-D Navier-Stokes equations are applied to simulate the viscid fluid surrounding the bionic dolphin. The study focuses on quantitative problems about the fluid dynamics behind the specific motion law, including speed of movement, energy loss and working efficiency. The current results show that the self-yaw can be composed of two motions, autonomous propulsion and active steering. In addition, the degree of the flexible caudal fin can produce different yaw effects. The chordwise phase difference Ф is dominant in the propulsion function, while the spanwise phase difference δ has a more noticeable effect on the steering function. The pressure distribution on the surface of the dolphin and the wake vortex generated in the flow field reasonably reveal the evolution of self-yaw. It properly turns out that the dolphin can combine the spanwise flexible caudal fin and the chordwise flexible body to achieve self-yaw motion.

Chemically reacting viscous fluid flow on a permeable cylinder susceptible to oscillations

An analysis is accomplished for a natural convective flow of an isochoric and chemically reactive viscid fluid around an impetuously commenced oscillating vertical cylinder encapsulated in a porous structure. The governing problem comprising of a system of conjoined nonlinear boundary layer equations with adapted boundary conditions are solved numerically by a Crank-Nicholson scheme. This scheme is one among the finite difference schemes which is an implicit, unconditionally stable and convergent scheme. The impacts of appurtenant parameters of an oscillating cylinder on velocity, temperature, concentration, viscous drag, exchange of thermal energy and mass transfer are presented graphically and interpreted. Major findings of the study disclose the fact that oscillations with higher phase angle reinforce the rate of heat and mass transfer. The behaviors of the streamlines and isotherms of the fluid are also presented and discussed.

Numerical Analysis of Magnetohydrodynamic Navier’s Slip Visco Nanofluid Flow Induced by Rotating Disk with Heat Source/Sink

Current exertion is made to depict and search out the flow features imparted to viscid fluid flow over a rotational disk. Impression of magnetic field with rotating fluid is generated by interacting it in radial direction. Nano structured particles with magnetized fluid are also incorporated in the upshot of chemical reaction and absorptive/generative heat induction. Von Kumaran procedure is executed to obtain flow narrating differential expressions. Flow pattern regarding thermal, momentum profiles are comprehended with the support of shooting method and Runge-Kutta methods. Furthermore, to get more realistic view of result description computational algorithm is modified by improving Runge-Kutta coefficients with Cash and Carp method. The aspects of flow controlling parameters like momentum slip parameter, magnetic strength parameter, Brownian motion parameter, thermophoresis parameter are adorned in sketches. Findings of these architects are accumulated in conclusion section.

Frictionless mobility of submicron particles in model viscid fluid

The mechanism of inter- and intracellular diffusional transport by vesicles in living organisms is poorly understood at the molecular scale. The diffusion of submicron and nanoparticles in dense media has been treated by numerous theoretical models. We face this problem experimentally using Mössbauer spectroscopy. On a characteristic for this method narrow time scale (≈10−7 s), the velocity distribution of 120 nm spherical Fe2O3 particles suspended in a 60% water solution of sucrose was determined by analyzing the 57Fe Mössbauer spectral line profile. The particles usually exhibit classical Brownian motion, but their main diffusion mechanism is related to infrequent (f ≈ 106 s−1) but distant (d ≈ 1 nm) translations. During such movements, the particles experience a minimal friction described by the temporal local viscosity, ηloc ≈ 28 μPa·s.

Acoustic Streaming and Its Applications

Broadly speaking, acoustic streaming is generated by a nonlinear acoustic wave with a finite amplitude propagating in a viscid fluid. The fluid volume elements of molecules, d V , are forced to oscillate at the same frequency as the incident acoustic wave. Due to the nature of the nonlinearity of the acoustic wave, the second-order effect of the wave propagation produces a time-independent flow velocity (DC flow) in addition to a regular oscillatory motion (AC motion). Consequently, the fluid moves in a certain direction, which depends on the geometry of the system and its boundary conditions, as well as the parameters of the incident acoustic wave. The small scale acoustic streaming in a fluid is called “microstreaming”. When it is associated with acoustic cavitation, which refers to activities of microbubbles in a general sense, it is often called “cavitation microstreaming”. For biomedical applications, microstreaming usually takes place in a boundary layer at proximity of a solid boundary, which could be the membrane of a cell or walls of a container. To satisfy the non-slip boundary condition, the flow motion at a solid boundary should be zero. The magnitude of the DC acoustic streaming velocity, as well as the oscillatory flow velocity near the boundary, drop drastically; consequently, the acoustic streaming velocity generates a DC velocity gradient and the oscillatory flow velocity gradient produces an AC velocity gradient; they both will produce shear stress. The former is a DC shear stress and the latter is AC shear stress. It was observed the DC shear stress plays the dominant role, which may enhance the permeability of molecules passing through the cell membrane. This phenomenon is called “sonoporation”. Sonoporation has shown a great potential for the targeted delivery of DNA, drugs, and macromolecules into a cell. Acoustic streaming has also been used in fluid mixing, boundary cooling, and many other applications. The goal of this work is to give a brief review of the basic mathematical theory for acoustic microstreaming related to the aforementioned applications. The emphasis will be on its applications in biotechnology.

Wave propagation in a non-homogeneous magneto-thermo-electro-elastic disc of polygonal cross sections immersed in an in viscid fluid

The study of non-homogeneous wave propagation in a magneto-thermo-electro-elastic polygonal disc immersed in fluid is carried out in this paper using linear theory of elasticity along with Fourier expansion collocation method. The considered material is non-homogeneous transversely isotropic material and the wave equation is applied under the assumption of disc immersed in an in viscid fluid. The analytical results have been obtained for triangle, square, pentagon and hexagonal cross-sections of disc. The stress, strain, mechanical displacement, electrical displacement and temperature distribution have been represented graphically with varying non-homogeneous parameter.

Nodular hepatocellular carcinoma in a Labrador dog with metastases

A 10 year old male Labrador retriever was presented for necropsy with the clinical history of vomition and pain on palpation of abdomen. Ultrasound examination revealed enlarged and abnormal liver borders. Haemato-biochemical studies revealed anaemia, leukocytosis and elevated liver specific enzymes. Necropsy examination of the carcass revealed mottled liver with multiple variably sized round, discrete to coalescing grey white to brown soft friable nodules on all the lobes. A few nodules were cystic with accumulation of viscid fluid. Similarly, multifocal variable sized dark red nodules were also found randomly scattered on both the lungs. Pancreas and kidneys also revealed metastasis. Histologically, the liver nodules appeared as nodular hepatocellular carcinoma with adenoid pattern. Metastatic foci were observed in the lungs, pancreas and kidneys. Immunohistochemical detection of tumour markers such as alpha fetoprotein, proliferating cell nuclear antigen, pancytokeratin, vimentin, chorioembryonic antigen were carried out for differential diagnosis.

Differential invariants for spherical flows of a viscid fluid

Abstract Symmetries and the corresponding algebras of differential invariants of viscid fluids on a sphere are given. Their dependence on thermodynamical states of media is studied, and a classification of thermodynamical states is given.

Conditions and phase shift of fluid resonance in narrow gaps of bottom mounted caissons

This paper studies the viscid and inviscid fluid resonance in gaps of bottom mounted caissons on the basis of the plane wave hypothesis and full wave model. The theoretical analysis and the numerical results demonstrate that the condition for the appearance of fluid resonance in narrow gaps is kh=(2n+1)π (n=0, 1, 2, 3, …), rather than kh=nπ (n=0, 1, 2, 3, …); the transmission peaks in viscid fluid are related to the resonance peaks in the gaps. k and h stand for the wave number and the gap length. The combination of the plane wave hypothesis or the full wave model with the local viscosity model can accurately determine the heights and the locations of the resonance peaks. The upper bound for the appearance of fluid resonance in gaps is 2b/L<1 (2b, grating constant; L, wave length) and the lower bound is h/b≤1. The main reason for the phase shift of the resonance peaks is the inductive factors. The number of resonance peaks in the spectrum curve is dependent on the ratio of the gap length to the grating constant. The heights and the positions of the resonance peaks predicted by the present models agree well with the experimental data.

Biological Flora of the British Isles: Neottia cordata

Abstract This account presents information on all aspects of the biology of Neottia cordata (L.) Rich. (Lesser Twayblade; Listera cordata (L.) R. Br.) that are relevant to an understanding of its ecological characteristics and behaviour. The main topics are presented within the standard framework of the Biological Flora of the British Isles: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, reproductive characteristics, herbivores, history and conservation. Neottia cordata is an inconspicuous orchid, confined to humid heathlands and woodlands rich in bryophytes in the British Isles. Neottia cordata is a polycarpic, perennial herb with populations maintained predominantly by vegetative reproduction from root suckers. The main perennating organ is a short rhizome that produces two new internodes each year. The long adventitious roots are mainly colonized not only by mycorrhizal basidiomycetes from the Sebacinales (clade B, Serendipitaceae) but also by several other fungal groups. The species flowers from mid‐April to August depending on latitude and altitude. The flowers possess a sensitive rostellum that releases a viscid fluid when touched, ensuring that the pollinia are glued to the pollinator. The flowers produce nectar and are pollinated mainly by fungus gnats (Mycetophilidae and Sciaridae). Between 60% and 80% of open flowers set fruits. Neottia cordata is classified as Least Concern in Great Britain. It is still locally abundant in north and west Scotland but has declined elsewhere, especially at lower altitudes, because of burning on grouse moors, drainage of swamps and cutting of wet forests. It is likely to have been under‐recorded throughout its range, particularly in earlier surveys, due to its inconspicuousness.

Numerical Solution of the Proces of Hydroplaning at Wheels with Envelope

In this paper is presented a study for the envelope’s properties settlement regarding the process of hydroplaning. The phenomenon of hydroplaning is calculable with the aid of the equations of motions for the viscid fluid in streamline regime for thin layers of fluid supposed to crush. Conclusively this paper offers the base of determinations prequisites to settle the envelope’s properties concerning to the phenomenon of hydroplaning.

Biological Flora of the British Isles:Neottia ovata

SummaryThis account presents information on all aspects of the biology ofNeottia ovata(L.) Bluff &amp; Fingerh. (Common Twayblade;Listera ovata(L.) R. Br.) that are relevant to an understanding of its ecological characteristics and behaviour. The main topics are presented within the standard framework of theBiological Flora of the British Isles: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, reproductive characteristics, herbivores, history and conservation.Neottia ovatais one of the commonest orchids in the British Isles. It occupies a wide range of habitats from lowlands to mountains and from wet to dry sites: deciduous broadleaved and mixed woodland, forest edges, calcareous grassland and scrub, hedgerows, dry meadows, pastures, sand dunes, fens, floodplains and some anthropogenic sites.Neottia ovatais a perennial herb whose populations are maintained predominantly by sexual reproduction, as vegetative spread is limited. The main perennating organ is a horizontal rhizome that produces a new internode every year. The numerous adventitious roots are mainly colonized by Basidiomycota from Sebacinales (Clade B) but also by several other fungal groups. Dormancy, that is the failure of above‐ground parts to appear in a growing season, followed by reappearance of full‐sized photosynthetic plants in subsequent seasons, has been occasionally observed and typically lasts for one, or sometimes 2 years.The species flowers from early May to the beginning of July, or August at higher altitudes. The flowers of the genusNeottiapossess a sensitive rostellum that releases a viscid fluid when it is touched, gluing the pollinia to the pollinator.N. ovatais pollinated mainly by three insect groups: ichneumonids, sawflies and beetles. The mean fraction of flowers setting fruit isc. 40%, but it depends on weather conditions: in rainy weather, it decreases to 10%, and in warm, dry weather, it can increase to 100%. Spontaneous autogamy is rare (1% of flowers).Neottia ovatais classified as a species of Least Concern in Great Britain. Although it appears well adapted to countryside changes, thanks to its wide habitat range, the species has vanished from almost 30% of its historical sites in Britain and Ireland. Agricultural activities are mainly responsible for losses ofN. ovatasites in the lowlands.

Ultrafast frame rate microscopy of microbubble oscillations: Current studies employing the UPMC-Cam

Ultrasound-stimulated microbubbles are clinically employed for diagnostic imaging and have been shown to be a feasible therapeutic strategy for localized drug and gene delivery applications. In order to investigate microbubble oscillation dynamics, the University of Pittsburgh Medical Center has developed the UPMC-Cam—an ultrafast imaging system capable of recording 128 frames at up to 25 million frames per second, one of only two in the world currently in use. Current studies include elucidating the effect of fluid viscosity on microbubble behavior. At lower pressures (0.1–0.25 MPa), an increase in fluid viscosity from 1 to 4 cP alters the fundamental and second-harmonic oscillation amplitudes in a bubble size-dependent manner, related to resonance. At higher pressures (0.5–1.5 MPa), a significant decrease in the propensity for microbubble fragmentation was observed in the more viscid fluid environment. Additionally, studies aimed at gaining physical insights into sonoporation have been conducted in which individual bubbles lay adjacent to a cell monolayer. These studies have revealed a maximum microbubble expansion threshold above which sonoporation occurs, likely related to the associated shear stresses exerted by a microbubble on the adjacent cell membrane. The UPMC-Cam has shown to be an invaluable tool for investigating biophysical-related phenomena over a wide range of ultrasound-microbubble applications.

Analysis of Loads and Response on Flexible Riser under the Combined Effects of Wave and Current

A three dimensional computational model is established for the analysis of loads and response of flexible riser in a wave-current coexisting environment. The viscid fluid is assumed incompressible. The flow field is described by continuity equation and Reynolds Average Navier-Stokes equations and solved with the discretization of Finite-Volume Method. The structure responses are analyzed employing finite element method based on three dimensional solid element. The loads and response are calculated through the CFD module System Coupling in software package ANSYS14.5. The results show that the vibration equilibrium position of riser offsets along with the direction of current when wave and current are in the same direction, the response of the riser is larger than that only in wave, the vibration amplitude increases with the current and the results are opposite to the above when wave and current has the opposite direction.