Technology & Engineering
Fluid Dynamics
Fluid dynamics is the study of fluids in motion, including liquids and gases. It explores how these substances behave and interact with their environment, encompassing phenomena such as turbulence, flow patterns, and pressure. This field is crucial in various engineering applications, from designing aircraft and vehicles to understanding weather patterns and ocean currents.
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11 Key excerpts on "Fluid Dynamics"
- Jonathan Wickert, Kemper Lewis, Jonathan Wickert(Authors)
- 2020(Publication Date)
- Cengage Learning EMEA(Publisher)
220 CHAPTER OBJECTIVES Fluids Engineering CHAPTER 6 ■ Recognize the application of fluids engineering to such diverse fields as microfluidics, aerodynamics, sports technology, and medicine. ■ Explain in technical terms the differences between a solid and a fluid, and the physical meanings of a fluid’s density and viscosity properties. ■ Understand the characteristics of laminar and turbulent fluid flows. ■ Calculate the dimensionless Reynolds number, which is the most significant numerical value in fluids engineering. ■ Determine the magnitudes of the fluid forces known as buoyancy, drag, and lift in certain applications. ■ Analyze the volumetric flow rate and pressure drop of fluids flowing through pipes. ▸ ▸ 6.1 Overview I n this chapter, we introduce the subject of fluids engineering and its role in applications as diverse as aerodynamics, biomedical and biological engineering, piping systems, microfluidics, and sports engineering. The study of fluids, which are classified as either liquids or gases, is further broken down into the areas of fluid statics and dynamics. Mechanical engineers apply the principles of fluid statics to calculate the pressure and buoyancy force of fluids acting on stationary objects, including ships, tanks, and dams. Fluid Dynamics refers to the behavior of liquids or gases when they are moving or when an object is moving through an otherwise stationary fluid. Hydrodynamics and aerodynamics are the specializations focusing on the motions of water and air, which are the most common fluids encountered in engineering. Those fields encompass not only the design of high-speed vehicles but also the motions of oceans and the atmosphere. Some engineers and scientists apply sophisticated computational models to simulate and understand interactions among the atmosphere, oceans, and global climates (Figure 6.1).
- Jonathan Wickert, Jonathan Wickert, Kemper Lewis(Authors)
- 2016(Publication Date)
- Cengage Learning EMEA(Publisher)
220 CHAPTER OBJECTIVES Fluids Engineering CHAPTER 6 6-1 Recognize the application of fluids engineering to such diverse fields as microfluidics, aerodynamics, sports technology, and medicine. 6-2 Explain in technical terms the differences between a solid and a fluid, and the physical meanings of a fluid’s density and viscosity properties. 6-3 Understand the characteristics of laminar and turbulent fluid flows. 6-4 Calculate the dimensionless Reynolds number, which is the most significant numerical value in fluids engineering. 6-5 Determine the magnitudes of the fluid forces known as buoyancy, drag, and lift in certain applications. 6-6 Analyze the volumetric flow rate and pressure drop of fluids flowing through pipes. ▸ ▸ 6.1 Overview I n this chapter, we introduce the subject of fluids engineering and its role in applications as diverse as aerodynamics, biomedical and biological engineering, piping systems, microfluidics, and sports engineering. The study of fluids, which are classified as either liquids or gases, is further broken down into the areas of fluid statics and dynamics. Mechanical engineers apply the principles of fluid statics to calculate the pressure and buoyancy force of fluids acting on stationary objects, including ships, tanks, and dams. Fluid Dynamics refers to the behavior of liquids or gases when they are moving or when an object is moving through an otherwise stationary fluid. Hydrodynamics and aerodynamics are the specializations focusing on the motions of water and air, which are the most common fluids encountered in engineering. Those fields encompass not only the design of high-speed vehicles but also the motions of oceans and the atmosphere. Some engineers and scientists apply sophisticated computational models to simulate and understand interactions among the atmosphere, oceans, and global climates (Figure 6.1).
No longer available |Learn more- Michael Clifford(Author)
- 2014(Publication Date)
- CRC Press(Publisher)
1 1.1 Introduction Fluid Dynamics is the study of the dynamics of fluid flow. Here we learn how flows behave under different external forces and conditions. In a sense this is similar to rigid body dynamics in physics, where Newton’s second law is used to describe the motion of rigid bodies. Here, we must apply Newton’s second law to fluid flows in a different way since fluids do not behave exactly like rigid bodies. This will be discussed in Section 1.2, where basic equations to describe fluid motion are derived and explained. Some discussions on laminar and turbulent flows are also given there, paving the way for what will follow. The fluid that we deal with in this unit is a viscous fluid, so the velocity of fluid flow becomes zero at the solid surface. The consequence of this no-slip condition is that flow velocity changes from zero at the wall to the free-stream value sufficiently far away from the wall surface. This thin layer is called the boundary layer , an important concept in Fluid Dynamics, which explains how the fluid forces are generated. So, in Section 1.3, we learn the basic behaviour of boundary layers to be able to estimate the viscous drag acting on the solid surface. The boundary layers over solid bodies behave differently depending on their shape. For example, the drag force acting on sports cars is much less than that on pickup trucks, where the boundary layer is separated from the body surface of vehicle creating a strong flow disturbance. In Section 1.4 we study the streamlining strategy to reduce the drag force of immersed bodies. We also discuss how the drag of immersed bodies is affected by the Reynolds number as well as the wall roughness. Pipes and ducts are important engineering components used in many fluid systems. It is important, therefore, that the flow resistance can be correctly estimated for different type of ducts and pipes.
- B. S. Mazumder, T. I. Eldho(Authors)
- 2023(Publication Date)
- CRC Press(Publisher)
2 Fundamental Fluid Properties and DefinitionsDOI: 10.1201/9781003000020-22.1 Introduction
Fluid mechanics is a branch of physics concerned with the mechanics of fluid flows. The study of fluid flow has been described with the support of fundamental laws of mechanics (Schlichting, 1968) . It has a wide range of applications in almost all branches of engineering fields including civil engineering, mechanical engineering, chemical engineering, aerospace engineering, agriculture engineering, ocean engineering, and others. Apart from the engineering profession, the principles of fluid mechanics are also used in all branches of sciences such as geophysics, astrophysics, physical chemistry, biomechanics, biomedical, meteorology, atmospherics, etc. It is one of the fastest rising basic sciences whose principles show applications in all aspects of daily life. For example, in civil engineering, the principles of fluid mechanics are used to design drainage systems, water networks, water-resisting structures such as dams and reservoirs, construction and foundation of bridge piers, river bank protection, river management, protection of coastal and harbor areas, etc. Moreover, designs of various types of ships, recreation boats, and barges or vessels for transportation in rivers and oceans associated with the field of naval architecture are based on the principles of fluid mechanics.The study of fluid behavior can be divided into three categories: statics, kinematics, and dynamics. In the static case, the fluid elements are acted upon by the forces at rest. The static pressure forces on an immersed body in fluid are determined from the static analysis. In the case of kinematics of fluids, it deals with the geometry of fluid motion: study of translation, rotation, and deformation of fluid particles. This is useful for describing the motion of a particle and visualizing the flow patterns. In the dynamic case, the analysis involves considering the forces acting on the fluid particles in motion with respect to one another that cause acceleration of fluid. To determine the fluid flow pattern and its surroundings in motion, the dynamic analysis of a fluid in motion is required. In this chapter, the description of fundamental fluid properties and a fundamental definition of various terms used in Fluid Dynamics and fluvial hydraulics are briefly discussed.
- Bhimsen K. Shivamoggi(Author)
- 2022(Publication Date)
- Wiley(Publisher)
1 Part I Basic Concepts and Equations of Fluid Dynamics 3 1 Introduction to the Fluid Model While dealing with a fluid, in reality, one deals with a system that has many particles which interact with one another. The main utility of Fluid Dynamics is the ability to develop a formalism which deals solely with a few macroscopic quantities like pressure, while ignoring the details of the particle interactions. Therefore, the techniques of Fluid Dynamics have often been found useful in modeling systems with complicated interactions (which are either not known or very difficult to describe) between the constituents. Thus, the first successful model of the nuclear fission of heavy elements was the liquid drop model of the nucleus, which treats the nucleus as a fluid. This replaces the many body problem of calculating the interactions of all the protons and neutrons with the much simpler problem of calculating the pressures and surface tension in this fluid. 1 Of course, this treatment gives only a very rough approximation to reality, but it is nonetheless a very useful way of approaching the problem. The primary purpose of Fluid Dynamics is to study the causes and effects of the motion of fluids. Fluid Dynamics seeks to construct a mathematical the- ory of fluid motion based on the smallest number of dynamical principles, which are adequate to correlate the different types of fluid flow as far as their macroscopic features are concerned. In many circumstances, the incompress- ible, inviscid fluid model is sufficiently representative of real fluid properties to provide a satisfactory account of a great variety of fluid motions. It turns out that such a model makes accurate predictions for the airflow around streamlined bodies moving at low speeds. While dealing with streamlined bodies (which minimize flow-separation) in flows of fluids of small viscosities, one may divide the flow field into two parts.
eBook - PDFThe Coen & Hamworthy Combustion Handbook
Fundamentals for Power, Marine & Industrial Applications
- Stephen Londerville, Charles E. Baukal Jr., Stephen Londerville, Charles E. Baukal Jr.(Authors)
- 2013(Publication Date)
- CRC Press(Publisher)
182 References ................................................................................................................................................................................ 182 154 The Coen & Hamworthy Combustion Handbook at an exponential rate. Fluid dynamics is a broad sub-ject because it is an important tool used in many engi-neering fields, for example, turbulence, acoustics, and aerodynamics. Fluid Dynamics plays an important role in the design and operation of combustion equipment. For example, industrial boilers require analysis and control of the flow of air, steam, fuel, and hot combustion products through complex networks of pipes, ducts, valves, dampers, reg-ulators, pumps, fans, etc. Engineers rely extensively on empirical fluid dynamic models, computational fluid dynamic models, cold flow physical models, and experi-ence gained from day-to-day observation of flow dynam-ics to help facilitate and guide in the design of combustion equipment. In general, the more familiar operators are with the flow dynamics associated with their combustion equipment, the better they are equipped to operate and troubleshoot their systems in a safe and efficient manner. 8.2 Properties of Fluids In fluid mechanics, fluid properties are used to charac-terize the behavior of the given fluid. Many of the topics covered in previous chapters will be briefly covered and explained in the context of Fluid Dynamics. 8.2.1 Density Density is defined as the ratio of mass to volume. For a solid, density is constant at every point of the mate-rial. However, for a fluid, the density will vary, depend-ing on selected control volume. If the control volume is infinitesimally small, the density of the given fluid will fluctuate wildly as the number of molecules varies over time. Likewise, a control volume which is too large will also affect the density due to macroscale variations.
eBook - PDF- Robert Resnick, David Halliday, Kenneth S. Krane(Authors)
- 2016(Publication Date)
- Wiley(Publisher)
351 Fluid Dynamics W e now turn from fluid statics to the dynamics of fluids in motion. We use familiar concepts to analyze Fluid Dynamics, including Newton’s laws of motion and the conservation of energy. In this chapter we apply these principles to fluids, which are described using variables such as pressure and density that we introduced in Chapter 15. We begin with a simplified model of fluid flow, in which we ignore dissipative forces. This approach is similar to our previous study of particle dynamics, in which we at first ignored dissipative (frictional) forces. An advantage of this approach is that it permits an analysis in terms of conservation of mechanical energy, as we did in Chapter 12 in the case of particles. Later in this chapter we give a brief description of the interesting and unusual results that occur in real fluids when dissipative forces, called viscous forces, are taken into account. 16-1 GENERAL CONCEPTS OF FLUID FLOW One way of describing the motion of a fluid is to divide the fluid into infinitesimal volume elements, which we may call fluid particles, and to follow the motion of each particle. If we knew the forces acting on each fluid particle, we could then solve for the positions and velocities of each particle as functions of the time. This procedure, which is a direct generalization of particle mechanics, was first developed by Joseph Louis Lagrange (1736 – 1813). Because the number of fluid particles is generally very large, using this method is a formidable task. There is a different treatment, developed by Leonhard Euler (1707 – 1783), that is more convenient for most pur- poses. In it we give up the attempt to specify the history of each fluid particle and instead specify the density and the velocity of the fluid at each point in space at each instant of time.
eBook - PDFThe John Zink Hamworthy Combustion Handbook
Volume 1 - Fundamentals
- Charles E. Baukal Jr.(Author)
- 2012(Publication Date)
- CRC Press(Publisher)
306 229 Fundamentals of Fluid Dynamics Fluid Dynamics plays an important role in the design and operation of combustion equipment. For example, industrial burners and flares require analysis and control of the flow of air, steam, fuel, and hot combustion prod-ucts through complex networks of pipes, ducts, valves, dampers, regulators, pumps, etc. Engineers rely exten-sively on empirical fluid dynamic models, computa-tional fluid dynamic models, cold flow physical models, and experience gained from day-to-day observation of flow dynamics to help facilitate and guide in the design of combustion equipment. Fluid Dynamics also plays a key role in the operation of flare and burner equipment. In general, the more familiar the operators are with the flow dynamics associated with their combustion equip-ment, the better they are equipped to operate and trou-bleshoot their system in a safe and efficient manner. The purpose of this chapter is to (1) provide the reader with some of the practical fluid dynamic concepts and terminology commonly used in the burner and flare industry, (2) demonstrate several ways combustion engineers apply Fluid Dynamics to assist in the design of combustion equipment, and (3) describe some of the instrumentation often used in the combustion industry. 9.2 Properties of Fluids The properties of a fluid (gas or liquid) describe its physical characteristics. This section presents a brief description of these properties and discusses how the properties of a mixture are calculated. For a list of additional gas properties, the reader is referred to the following sources: Geerssen, 10 Turns, 11 and Bartok and Sarofim. 12 9.2.1 Density of Gases Atmospheric air is a mixture of many gases plus water vapor and other pollutants. Aside from pollutants, which may vary considerably from place to place, the composition of dry air is relatively constant; the compo-sition varies slightly with time, location, and altitude.
eBook - PDFTransport Phenomena in Biomedical Engineering
Principles and Practices
- Robert A. Peattie, Robert J. Fisher, Joseph D. Bronzino, Donald R. Peterson, Robert A. Peattie, Robert J. Fisher, Joseph D. Bronzino, Donald R. Peterson(Authors)
- 2012(Publication Date)
- CRC Press(Publisher)
The primary objective of this chapter is to summarize the most important concepts of fluid dynam-ics, as hydrodynamic and hemodynamic principles have many important applications to physiology, pathophysiology, and tissue engineering. In fact, the interaction of fluids and supported tissue is of paramount importance to tissue development and viability, both in vivo and in vitro . The strength of adhesion and dynamics of detachment of mammalian cells from engineered biomaterials and scaffolds are important subjects of ongoing research [5], as are the effects of shear on receptor–ligand binding at the cell–fluid interface. Flow-induced stress has numerous critical consequences for cells, altering trans-port across the cell membrane, receptor density and distribution, binding affinity and signal generation with subsequent trafficking within the cell [6]. In addition, design and use of perfusion systems such as membrane biomimetic reactors and hollow fibers is most effective when careful attention is given to issues of hydrodynamic similitude. Similarly, understanding the role of fluid mechanical phenomena in arterial disease and subsequent therapeutic applications is clearly dependent on the appreciation of hemodynamics. Understanding of fluid phenomena is also crucial for processing and transport applications not taking place within living systems. For example, the ability to generate nanoscale entities, as in emul-sions and suspensions, requires knowledge of multiphase flow and turbulent mixing concepts. Typical uses are (1) “bottom-up” drug crystal size control, (2) permeation enhancement materials for dispersion 4 -3 Fluid Dynamics for Bio Systems into immunoprotective barrier membranes, as in improving oxygen supply to encapsulated cells/tissue systems, and (3) creating chaperones for specific targets as in imaging and/or drug delivery. For further details and other important applications, the reader will find the following sources more appropriate [7–17].
eBook - ePubFluid and Thermal Dynamics Answer Bank for Engineers
The Concise Guide with Formulas and Principles for Students and Professionals
- Ethirajan Rathakrishnan(Author)
- 2023(Publication Date)
- BrownWalker Press(Publisher)
(iii) less than five percent 2.The theoretical science based on the concept of an ideal fluid is termed (i) thermodynamics (ii) real fluid flow (iii) classical hydrodynamics 3.Science of flow physics developed from experimental studies of the applied science is known as (i) fluid mechanics (ii) hydrodynamics (iii) hydraulics 4.The study that deals with fluid elements, at rest with respect to one another and therefore is free of shearing stresses is known as (i) dynamics of fluids (ii) statics (iii) flow physics 5.The study that deals with the determination of the effects of the fluid and its surroundings on the motion of the fluid is known as (i) dynamics (ii) kinematics (iii) fluid flow 6.Under normal conditions of pressures and temperatures for most gases the molecular density is(i) 6.225 × 1023 molecules per m3(ii) 2.7 × 1025 molecules per m3(iii) 9.73 × 1023 molecules per m37.The mean free path, the statistical average distance which molecules travel between collisions, of atmospheric air is (i) 100 nm (ii) between 10 nm and 25 nm (iii) between 50 nm and 70 nm 8.The friction forces that give rise to a fluid property called (i) friction (ii) shear (iii) viscosity9.Though the theory of ideal fluids fails to account for viscous and compressibility effects in actual fluid flow processes, it gives reasonably reliable results in the calculation of lift, induced drag and wave motion for gas flow at low velocity and for water. This branch of Fluid Dynamics is called
eBook - ePub- Zeki Berk(Author)
- 2008(Publication Date)
- Academic Press(Publisher)
Chapter 2. Fluid Flow
2.1. Introduction
The majority of industrial food processes involve fluid movement. Liquid foods such as milk and juices have to be pumped through processing equipment or from one container to another. In a blast freezer, a rapid stream of cold air is blown over the food. In a wheat mill, the grain, the milled intermediates and the final products are most often conveyed in a stream of air (pneumatic conveying). Essential process service media (utilities) such as water, steam and various gases have to be distributed about the plant in properly designed pipelines. A number of important unit operations such as filtration, pressing and mixing are, essentially, particular applications of fluid flow. The mechanism and rate of energy and mass transfer are strongly dependent on flow characteristics. Finally, the sensory quality of many liquid and semi-liquid foods depends, to a large extent, on the flow properties of the product.This chapter consists of four parts. The first part deals with the study of fluids in motion. This is the realm of a discipline known as ‘Fluid Dynamics’. The second part is about the flow and deformation properties of fluids. This is the subject matter of the science called ‘rheology’. Technical elements such as pumps and piping, used for conveying fluids are discussed in the third part. The fourth part deals with flow and flow-related phenomena involving particulate solids. Techniques for the measurement and control of flow are described in Chapter 5 .2.2. Elements of Fluid Dynamics
2.2.1. Viscosity
Consider a mass of fluid confined between two flat plates (Figure 2.1 ). The lower plate is held stationary. The upper plate moves in the x direction at a constant velocity vx
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