Top Research Papers on Fluid Mechanics

The author discusses some basic questions in fluid dynamics. He describes Newton's contribution to fluid dynamics in the second volume of the Principia. He presents a brief review of fluid dynamics since Newton, and discusses the nature and content of physics curricula in schools and universities. He also outlines some aspects of modern research.

Thoroughly revised and expanded, the new edition of this established textbook equips readers with a robust and practical understanding of experimental fluid mechanics. Enhanced features include improved support for students with emphasis on pedagogical instruction and self-learning, end-of-chapter summaries, 127 examples, 165 problems and refined illustrations, plus new coverage of digital photography, frequency analysis of signals and force measurement. It describes comprehensively classical and modern methods for flow visualisation and measuring flow rate, pressure, velocity, temperature, co...

An overview of the dynamics of the human heart is presented and the main goal is the discussion of its fluid mechanic features, particularly the interaction with the systemic and pulmonary circulations with which it is strongly connected.

This Special Issue of Energies features 11 scientific papers on the subject of turbulence and fluid mechanics [...]

the boundary conditions. It covers fundamental concepts of finite difference and finite volume methods for diffusion, convection-diffusion problems both for cartesian and non-orthogonal grids. The solution of algebraic equations arising due to finite difference and finite volume discretization are highlighted using direct and iterative methods. Pedagogical features including solved problems and unsolved exercises are interspersed throughout the text for better understanding. The textbook is primarily written for senior undergraduate and graduate students in the field of mechanical engineering ...

Fluid mechanics lies at the heart of many of the physical processes associated with the nascent deep-sea mining industry. The evolution and fate of sediment plumes that would be produced by seabed mining activities, which are central to the assessment of the environmental impact, are entirely determined by transport processes. These processes, which include advection, turbulent mixing, buoyancy, differential particle settling, and flocculation, operate at a multitude of spatiotemporal scales. A combination of historical and recent efforts that combine theory, numerical modeling, laboratory exp...

Contents Preface to the eighth edition 1 Fundamental Concepts Problems 2 Fluid Statics Problems 3 The Principles Governing Fluids in Motion Problems 4 The Momentum Equation 5. Physical Similarity and Dimensional Analysis Problems 6 Laminar Flow between Solid Boundaries Problems 7 Flow and Losses in Pipes and Fittings Problems 8 Boundary Layers, Wakes and other Shear Layers Problems 9 The flow of an Inviscid Fluid Problems 10 Flow with a Free Surface Problems 11 Compressible Flow of Gases Problems 12 Unsteady Flow Problems 13 Fluid Machines Problems Appendix 1 Units and Conversion Factors Appen...

This review provides a review of AFC in the normal lung, focuses on the mechanisms of impaired AFC, and then outlines the regulation of AFC.

The three-dimensional structure of one of the crucial joints in spider hydraulic actuation is presented, the fluid flow inside the spider leg is elucidated, and the rheological properties of hemolymph under physiological conditions are quantified.

The removal of unwanted entities or soiling material from surfaces is an essential operation in many personal, industrial, societal, and environmental applications. The use of liquid cleansers for ...

This review focuses on Leonardo da Vinci's work and thought related to fluid mechanics as it is presented in a lifetime of notebooks, letters, and artwork. It shows how Leonardo's remaining works offer a complicated picture of unfinished, scattered, and frequently revisited hypotheses and conclusions. It argues that experimentation formed an important mechanism for Leonardo's thought about natural fluid flows, which was an innovation to the scientific thinking of his day, but which did not always lead him to the conclusions of modern fluid mechanics. It highlights the multiple and ambiguous me...

An introduction and historical perspective of ML methods, in particular neural networks (NN), are provided and existing PIML applications to fluid mechanics problems are examined, especially in complex high Reynolds number flows.

The influence of fluid–fluid interfacial properties on the dynamics of viscoelastic thin liquid films bounded above by liquid–liquid interface and below by a horizontal solid plate is studied in this work. The present study allows for integration of both chemical and physical properties of the thin liquid film within the long wave approximation of the evolution equation for viscoelastic thin films. The effects of the contact angle, slippage and exposure time on interfacial film dynamics are verified. We demonstrate the importance of the interfacial tension due to surfactant concentration and t...

In the past few decades various particle image–based volumetric flow measurement techniques have been developed that have demonstrated their potential in accessing unsteady flow properties quantitatively in various experimental applications in fluid mechanics. In this review, we focus on physical properties and circumstances of 3D particle–based measurements and what knowledge can be used for advancing reconstruction accuracy and spatial and temporal resolution, as well as completeness. The natural candidate for our focus is 3D Lagrangian particle tracking (LPT), which allows for position, vel...

A look at fundamental aspects of fluid motion, including important fluid properties, regimes of flow, pressure variations in fluids at rest and in motion, fluid kinematics, and methods of flow description and analysis. This book describes the essential elements of kinematics, including Eulerian and Lagrangian mathematical descriptions of flow phenomena, and indicates the vital relationship between the two views.

Abstract Sash windows, or counter-balanced vertically sliding windows, are a common feature in domestic buildings. We describe a model for the ventilation flow rate through a sash window, when the indoor temperature is warmer than outdoors. Depending on the position of the neutral pressure level relative to the sash window, we identify three flow regimes and the critical height of the lower opening for the flow to transition from one regime to another. We perform laboratory experiments in a water tank to measure the flow rate for different sash window geometries, and compare our experimental r...

This article attempts to use the ideas from the field of complexity sciences to revisit the classical field of fluid mechanics. For almost a century, the mathematical self-consistency of Navier-Stokes equations has remained elusive to the community of functional analysts, who posed the Navier-Stokes problem as one of the seven millennium problems in the dawn of 21st century. This article attempts to trace back the historical developments of fluid mechanics as a discipline and explain the consequences of not rationalising one of the commonly agreed upon tenets - continuum hypothesis - in the co...

Most variational principles in classical mechanics are based on the principle of least action, which is only a stationary principle. In contrast, Gauss' principle of least constraint is a true minimum principle. In this paper, we apply Gauss' principle to the mechanics of incompressible flows, thereby discovering the fundamental quantity that Nature minimizes in most flows encountered in everyday life. We show that the magnitude of the pressure gradient over the domain is minimum at every instant of time. We call it the principle of minimum pressure gradient (PMPG). It turns a fluid mechanics ...

LBNP, and to a lesser extent VTC and ITD, represent promising headward fluid shift countermeasures, but will require future testing in analog and spaceflight environments.

The overlapping circadian (≈24-hour) rhythms in brain fluid biology and at the brain barriers are discussed to gain both a fundamental understanding of brain barriers alongside an understanding of the interactions between these fluids and the circadian timing system.

In order to study the rheological properties of aqueous magnetorheological fluids (MRFs) from microscopic point of view, an experimental observation method based on fluorescence confocal laser scanning microscope is proposed to clearly shown the chain shape of magnetic particles. Firstly, the mathematical model of the magnetic particles is established in a magnetic field using the magnetic dipole theory, and the MRFs with different volume fraction and different magnetic fields are investigated. Furthermore, an aqueous MRFs experiment is prepared, in which the magnetic particles are combined wi...

This document lists the following equipment purchases using DOD-University Research Instrumentation funds: equipment purchases, work stations, and Speciality Equipment for Work Stations.

Live imaging of MCCs in embryos of the frog Xenopus laevis shows that cilia bundles behave as active vortices that produce a flow field accurately represented by a local force applied to the fluid.

LagrangeBench is presented, the first benchmarking suite for Lagrangian particle problems, focusing on temporal coarse-graining and going beyond established position errors and introducing physical metrics like kinetic energy MSE and Sinkhorn distance for the particle distribution.

Placing mechanical devices into fast-moving tidal streams to generate clean and predictable electricity is a developing technology. This review covers the fundamental fluid mechanics of this applic...

SUMMARY On the basis of experimental investigations, numerical flow simulations were carried out on a fan with leading edge serrations. The fan operates in turbulent inflow and a good agreement with the experiment could be achieved. It was found that leading-edge serrations generate longitudinal vortices that are temporally and spatially stable and thus improve the flow over the airfoil. In addition, a vortex could be generated which reduces the leakage across the tip gap. The stabilization of the flow over the blade reduces the pressure fluctuations on the blade surface, which in turn leads t...

This article reviews and discusses the recent progresses of studies with the concept of “Computational plasma fluid mechanics.” Computational demonstrations show that the inhouse simulation codes such as PLasma All-Speed Turbulence with Implicit Pressure Code have captured hydrodynamic instabilities and reproduced flow dynamics in thermal plasma—nonionized gas coexisting systems. A unique method has made it feasible to study collective growth of binary alloy nanoparticles by numerical analysis. Smoothed Particle Hydrodynamics method with incompressibility modification has achieved complex beha...

Fluid mechanics, a fundamental discipline within engineering, has gained increasing significance across various fields due to continuous advancements in engineering science and technology. Its principles and methodologies find widespread application in aerospace, energy development, environmental protection, biomedicine, and beyond, serving as a cornerstone for technological progress. However, despite the expanding applications of fluid dynamics, challenges persist in integrating theory with practice in certain domains. This paper aims to synthesize exemplary applications of fluid mechanics in...

Fracturing fluid is the main cause of reservoir damage during hydraulic fracturing. Fracturing fluid will change the mechanical properties of reservoir rock, and the effect of proppant-propping hydraulic fractures will be affected. To study the changes and internal mechanism of sandstone mechanical properties after guar gum fracturing fluid damage, triaxial compression experiments, core flow experiments, scanning electron microscopy, and nuclear magnetic resonance tests were carried out on sandstone cores before and after damage. The results showed that: (1) The compressive strength and el...

This paper reviews ML and DL research for fluid dynamics, presents algorithmic challenges and discusses potential future directions.

Abstract The 2021 Nobel Prize in Physics recognizes advances in the understanding of complex systems, and underscores that ‘complex’ does not mean ‘imponderable’.

An overview on the historical evolution of fluid mechanical models of UUT that utilize theoretical, computational, and experimental approaches is provided.

This review discusses human reproduction starting with the nonpregnant uterus through implantation, delivery, and lactation and breastfeeding, and examines the role of reproductive fluids such as amniotic fluid and vernix caseosa, and how force is transferred during labor.

Optical flow methods have been developed over the past two decades for application to PIV images with the goal of acquiring higher resolution measurements of the velocity field than conventional cross-correlation-based techniques. Numerous optical flow velocimetry (OFV) algorithms have been devised to solve the ill-posed optical flow problem, with various physics-inspired strategies to tailor them to fluid flows. While OFV can be applied to continuous scalar fields, it has demonstrated the most success on images of tracer particles, i.e.\ traditional planar PIV images. Compared to state-of-t...

Providing a modern approach to classical fluid mechanics, this textbook presents an accessible and rigorous introduction to the field, with a strong emphasis on both mathematical exposition and physical problems. It includes a consistent treatment of a broad range of fluid mechanics topics, including governing equations, vorticity, potential flow, compressible flow, viscous flow, instability, and turbulence. It has enhanced coverage of geometry, coordinate transformations, kinematics, thermodynamics, heat transfer, and nonlinear dynamics. To round out student understanding, a robust emphasis o...

Orographic wakes have important effects in the atmosphere and oceans as a source of waves and vortices. The induced drag forces influence the atmospheric winds and oceanic currents, Some of the largest and most persistent circulation errors in global numerical weather prediction and climate models are still attributable to the inadequate representation of this topographic drag. In oceanic canyons, wake effects lead to vertical mixing and upwelling. Orographic effects are also expected to play an important role at the outer boundary of planetary liquid cores, with influence on the magnetic fiel...

This is an idiosyncratic survey of statistical fluid mechanics centering on the Hopf functional differential equation. Using the Burgers equation for illustration, we review several functional integration approaches to the theory of turbulence. We note in particular that some important contributions have been brought about by researchers working on wave propagation in random media, among which Uriel Frisch is not an exception. We also discuss a particular finite-dimensional approximation for the Burgers equation. This article is part of the theme issue ‘’Scaling the turbulence edifice (part 1)...

First International Symposium on Ultrasonic Doppler Methods for Fluid Mechanics and Fluid Engineering Paul Scherrer Institute, Villigen, Switzerland 9.

The findings of a difference in tracer velocities heralds the introduction into fluid mechanics of a general bipartite theory of fluid mechanics, bivelocity hydrodynamicics, differing from conventional hydrodynamics in situations entailing compressible flows and reducing to conventional hydRodynamics when the flow is incompressible, while being applicable to both liquids and gases.

Fundamental ML methodologies are outlined and their uses for understanding, modeling, optimizing, and controlling fluid flows are discussed and the strengths and limitations of these methods are addressed.

Turbulence in a fluid has two mutually contradictory aspects, that is, the apparent ran-domeness as a whole and the intrinsic determinicity due to the fluid-dynamical equations. In the traditional approarch to this subject, the velocity field of turbulence has been represented by the mean products of the turbulent velocities at several points and a time, and the equations governing the dynamical system composed of the mean velocity products are solved to obtain the mean velocity products as the deterministic functions in time. The works along this approach constitute the main body of turbulenc...

Starting with a review of vector fields and their integral curves, the book presents the basic equations of the subject: Euler and Navier–Stokes. Some solutions are studied next: ideal flows using conformal transformations, viscous flows such as Couette and Stokes flow around a sphere, shocks in the Burgers equation. Prandtl’s boundary layer theory and the Blasius solution are presented. Rayleigh–Taylor instability is studied in analogy with the inverted pendulum, with a digression on Kapitza’s stabilization. The possibility of transients in a linearly stable system with a non-normal operator ...

With the growing number of wind farms over the last decades and the availability of large datasets, research in wind-farm flow modeling - one of the key components in optimizing the design and operation of wind farms - is shifting towards data-driven techniques. However, given that most current data-driven algorithms have been developed for canonical problems, the enormous complexity of fluid flows in real wind farms poses unique challenges for data-driven flow modeling. These include the high-dimensional multiscale nature of turbulence at high Reynolds numbers, geophysical and atmospheric eff...

The article considers the homogeneous vortex motion of an inhomogeneous fluid in a stationary ellipsoidal cavity arbitrarily oriented with respect to the direction of a uniform gravity field using the Lagrange variables. Uniform vortex motion of a fluid is a motion in which the rotor speed for all particles has the same value, and depends only on time. The article shows that the equations of homogeneous vortex motion of a heavy inhomogeneous fluid are possible in an ellipsoidal cavity with a linear density distribution and proposes a geometric interpretation of fluid motion. Using the Lagrange...

Oscillatory instability emerges amidst turbulent states in experiments in various turbulent fluid and thermo-fluid systems such as aero-acoustic, thermoacoustic and aeroelastic systems. For the time series of the relevant dynamic variable at the onset of the oscillatory instability, universal scaling behaviors have been discovered in experiments via the Hurst exponent and certain spectral measures. By means of a center manifold reduction, the spatiotemporal dynamics of these real systems can be mapped to a complex Ginzburg–Landau equation with a linear global coupling. In this work, we show th...

This issue showcases a compilation of papers on fluid mechanics (FM) education, covering different sub topics of the subject [...]

In recent years, Jupyter Notebooks have become a very useful free and open‐source tool in teaching, as they allow you to combine text, images, mathematical expressions, links and code into a single document. This gives students an interactive document with which they can experiment and learn with the help of high‐level mathematical calculus. In Fluid Mechanics, it is very common for students to deal with complex computations that take away attention from the Mechanic, especially in advanced topics such as Rheology, Turbulence, or Boundary Layer. The subject “Advanced Fluid Mechanics” is an ele...

This invention provides a fluid mechanism that can arrange a plurality of fluid device units and external fluid devices mounted as a set on the fluid device units effectively and compactly. Each of the fluid device units is arranged with respective side surfaces in a longitudinal direction of the fluid device unit tightly attached, and the external fluid devices are arranged side-by-side external to and outside of the fluid device unit in the width direction. Furthermore, as for an introducing path and a discharging path that connect the external fluid devices and the fluid device unit, the in...

Two models, one based on the full equations of fluid dynamics and the other using lumped parameters, are presented, in which the astrocyte endfeet function as valves, regulating flow between the PVS and the ECS, where cardiac pulsations drive a net CSF flow consistent with prior experimental observations.

Abstract The paper review key results [1-14] of the joint researches conducted by IMech and IUSTI. In the First part, we review models and experimental results on the linear and nonlinear instability of a capillary jet including both axisymmetric and nonaxisymmetric disturbances. In the Second part, results on draw resonances, occurring during a glass fibre process are reviewed, as well as the unique optical models and methods developed to perform these studies.