This document discusses fluid mechanics and viscosity. It begins by defining a fluid and explaining that fluids deform continuously under shear forces rather than resist deformation like solids. It then discusses viscosity, defining it as a fluid's resistance to flow. Viscosity exists due to molecular collisions and momentum transfer between layers of a fluid. Methods for measuring viscosity include viscometers that apply shear stresses between fluid layers. Viscosity affects fluid dynamics, causes drag, and is accounted for in the Navier-Stokes equations.
Rheology is the science that study flow of fluids. Viscosity is the main parameter of flow. Newtonian & non newtonian are the two types of flow behavior according to newtons law of flow. non-newtonian flow can be plastic, pseudoplastic, dilatant, thixotropic, antithixotropic or rheopexy. viscosity can be determined by using various viscometers such as capillary viscometer, cup & bob viscometer, cone & plate viscometer, falling sphere viscometer, brookfield viscometer, etc. factors affeting viscosity are intrinsic, extrinsic or temperature dependence.
Fluid Mechanics introduction for UG students
Fluid properties
Reynolds experiment
Manometer
Orificemeter
Venturimeter
Pitot tube
Rotameter
Current flow meter
In fluid dynamics, laminar flow is characterized by fluid particles following smooth paths in layers, with each layer moving smoothly past the adjacent layers with little or no mixing. At low velocities, the fluid tends to flow without lateral mixing, and adjacent layers slide past one another like playing cards.
Stoke's Law calculates rate of destabilization of an emulsion by equating gravitational force with the opposing hydrodynamic force. Stoke's Law can be used to predict emulsion stability.
B.TECH. DEGREE COURSE
SCHEME AND SYLLABUS
(2002-03 admission onwards)
MAHATMA GANDHI UNIVERSITY,mg university, KTU
KOTTAYAM
KERALA
Module 1
Introduction - Proprties of fluids - pressure, force, density, specific weight, compressibility, capillarity, surface tension, dynamic and kinematic viscosity-Pascal’s law-Newtonian and non-Newtonian fluids-fluid statics-measurement of pressure-variation of pressure-manometry-hydrostatic pressure on plane and curved surfaces-centre of pressure-buoyancy-floation-stability of submerged and floating bodies-metacentric height-period of oscillation.
Module 2
Kinematics of fluid motion-Eulerian and Lagrangian approach-classification and representation of fluid flow- path line, stream line and streak line. Basic hydrodynamics-equation for acceleration-continuity equation-rotational and irrotational flow-velocity potential and stream function-circulation and vorticity-vortex flow-energy variation across stream lines-basic field flow such as uniform flow, spiral flow, source, sink, doublet, vortex pair, flow past a cylinder with a circulation, Magnus effect-Joukowski theorem-coefficient of lift.
Module 3
Euler’s momentum equation-Bernoulli’s equation and its limitations-momentum and energy correction factors-pressure variation across uniform conduit and uniform bend-pressure distribution in irrotational flow and in curved boundaries-flow through orifices and mouthpieces, notches and weirs-time of emptying a tank-application of Bernoulli’s theorem-orifice meter, ventury meter, pitot tube, rotameter.
Module 4
Navier-Stoke’s equation-body force-Hagen-Poiseullie equation-boundary layer flow theory-velocity variation- methods of controlling-applications-diffuser-boundary layer separation –wakes, drag force, coefficient of drag, skin friction, pressure, profile and total drag-stream lined body, bluff body-drag force on a rectangular plate-drag coefficient for flow around a cylinder-lift and drag force on an aerofoil-applications of aerofoil- characteristics-work done-aerofoil flow recorder-polar diagram-simple problems.
Module 5
Flow of a real fluid-effect of viscosity on fluid flow-laminar and turbulent flow-boundary layer thickness-displacement, momentum and energy thickness-flow through pipes-laminar and turbulent flow in pipes-critical Reynolds number-Darcy-Weisback equation-hydraulic radius-Moody;s chart-pipes in series and parallel-siphon losses in pipes-power transmission through pipes-water hammer-equivalent pipe-open channel flow-Chezy’s equation-most economical cross section-hydraulic jump.
Rheology is the science that study flow of fluids. Viscosity is the main parameter of flow. Newtonian & non newtonian are the two types of flow behavior according to newtons law of flow. non-newtonian flow can be plastic, pseudoplastic, dilatant, thixotropic, antithixotropic or rheopexy. viscosity can be determined by using various viscometers such as capillary viscometer, cup & bob viscometer, cone & plate viscometer, falling sphere viscometer, brookfield viscometer, etc. factors affeting viscosity are intrinsic, extrinsic or temperature dependence.
Fluid Mechanics introduction for UG students
Fluid properties
Reynolds experiment
Manometer
Orificemeter
Venturimeter
Pitot tube
Rotameter
Current flow meter
In fluid dynamics, laminar flow is characterized by fluid particles following smooth paths in layers, with each layer moving smoothly past the adjacent layers with little or no mixing. At low velocities, the fluid tends to flow without lateral mixing, and adjacent layers slide past one another like playing cards.
Stoke's Law calculates rate of destabilization of an emulsion by equating gravitational force with the opposing hydrodynamic force. Stoke's Law can be used to predict emulsion stability.
B.TECH. DEGREE COURSE
SCHEME AND SYLLABUS
(2002-03 admission onwards)
MAHATMA GANDHI UNIVERSITY,mg university, KTU
KOTTAYAM
KERALA
Module 1
Introduction - Proprties of fluids - pressure, force, density, specific weight, compressibility, capillarity, surface tension, dynamic and kinematic viscosity-Pascal’s law-Newtonian and non-Newtonian fluids-fluid statics-measurement of pressure-variation of pressure-manometry-hydrostatic pressure on plane and curved surfaces-centre of pressure-buoyancy-floation-stability of submerged and floating bodies-metacentric height-period of oscillation.
Module 2
Kinematics of fluid motion-Eulerian and Lagrangian approach-classification and representation of fluid flow- path line, stream line and streak line. Basic hydrodynamics-equation for acceleration-continuity equation-rotational and irrotational flow-velocity potential and stream function-circulation and vorticity-vortex flow-energy variation across stream lines-basic field flow such as uniform flow, spiral flow, source, sink, doublet, vortex pair, flow past a cylinder with a circulation, Magnus effect-Joukowski theorem-coefficient of lift.
Module 3
Euler’s momentum equation-Bernoulli’s equation and its limitations-momentum and energy correction factors-pressure variation across uniform conduit and uniform bend-pressure distribution in irrotational flow and in curved boundaries-flow through orifices and mouthpieces, notches and weirs-time of emptying a tank-application of Bernoulli’s theorem-orifice meter, ventury meter, pitot tube, rotameter.
Module 4
Navier-Stoke’s equation-body force-Hagen-Poiseullie equation-boundary layer flow theory-velocity variation- methods of controlling-applications-diffuser-boundary layer separation –wakes, drag force, coefficient of drag, skin friction, pressure, profile and total drag-stream lined body, bluff body-drag force on a rectangular plate-drag coefficient for flow around a cylinder-lift and drag force on an aerofoil-applications of aerofoil- characteristics-work done-aerofoil flow recorder-polar diagram-simple problems.
Module 5
Flow of a real fluid-effect of viscosity on fluid flow-laminar and turbulent flow-boundary layer thickness-displacement, momentum and energy thickness-flow through pipes-laminar and turbulent flow in pipes-critical Reynolds number-Darcy-Weisback equation-hydraulic radius-Moody;s chart-pipes in series and parallel-siphon losses in pipes-power transmission through pipes-water hammer-equivalent pipe-open channel flow-Chezy’s equation-most economical cross section-hydraulic jump.
FLUID IN MOTION
HYDRODYNAMICS
Hydrodynamics is the branch of physics which deals with the study of properties of fluids in motion.
Viscosity of the fluid
The reason behind the raise the temperature of oil lubrication system of turbo jet engine of aircraft was investigated which leads to damaging engine and costs the government huge expenses .it was found that main reason had been excessive heat from frailer oil thermostat t I designed and added a experiential valve to oil system. Which operated to cool down the oil temperature and increase efficiency of engine.
Understand the physical mechanism of convection and its classification.
Visualize the development of velocity and thermal boundary layers during flow over surfaces.
Gain a working knowledge of the dimensionless Reynolds, Prandtl, and Nusselt numbers.
Distinguish between laminar and turbulent flows, and gain an understanding of the mechanisms of momentum and heat transfer in turbulent flow.
Derive the differential equations that govern convection on the basis of mass, momentum, and energy balances, and solve these equations for some simple cases such as laminar flow over a flat plate.
Non dimensionalize the convection equations and obtain the functional forms of friction and heat transfer coefficients.
Use analogies between momentum and heat transfer, and determine heat transfer coefficient from knowledge of friction coefficient.
Relative Motion between the particles and a fluidUsman Shah
This slide will explain you the chemical engineering terms .Al about the basics of this slide are explain in it. The basics of fluid mechanics, heat transfer, chemical engineering thermodynamics, fluid motions, newtonian fluids, are explain in this process.
Introduction to FLUID MECHANICS and its applicationkyunsoosilva14
Introduction to FLUID MECHANICS and its application.
Understand the basic concepts of Fluid Mechanics.
Recognize the various types of fluid flow problems encountered in practice.
Model engineering problems and solve them in a systematic manner.
Have a working knowledge of accuracy, precision, and significant digits, and recognize the importance of dimensional homogeneity in engineering calculations.
Mechanics: The oldest physical science that deals with both stationary and moving bodies under the influence of forces.
Statics: The branch of mechanics that
deals with bodies at rest.
Dynamics: The branch that deals with
bodies in motion.
Fluid mechanics: The science that deals with the behavior of fluids at rest (fluid statics) or in motion (fluid dynamics), and the interaction of fluids with solids or other fluids at the boundaries.
Fluid dynamics: Fluid mechanics is also referred to as fluid dynamics by considering fluids at rest as a special case of motion with zero velocity.
Hydrodynamics: The study of the motion of fluids that can be approximated as incompressible (such as liquids, especially water, and gases at low speeds).
Hydraulics: A subcategory of hydrodynamics, which deals with liquid flows in pipes and open channels.
Gas dynamics: Deals with the flow of fluids that undergo significant density changes, such as the flow of gases through nozzles at high speeds.
Aerodynamics: Deals with the flow of gases (especially air) over bodies such as aircraft, rockets, and automobiles at high or low speeds.
Meteorology, oceanography, and hydrology: Deal with naturally occurring flows.
Stress: Force per unit area.
Normal stress: The normal component of a force acting on a surface per unit area.
Shear stress: The tangential component of a force acting on a surface per unit area.
Pressure: The normal stress in a fluid at rest.
Zero shear stress: A fluid at rest is at a state of zero shear stress.
When the walls are removed or a liquid container is tilted, a shear develops as the liquid moves to re-establish a horizontal free surface.
The normal stress and shear stress at
the surface of a fluid element. For
fluids at rest, the shear stress is zero
and pressure is the only normal stress.
In a liquid, groups of molecules can move relative to each other, but the volume remains relatively constant because of the strong cohesive forces between the molecules. As a result, a liquid takes the shape of the container it is in, and it forms a free surface in a larger container in a gravitational field.
A gas expands until it encounters the walls of the container and fills the entire available space. This is because the gas molecules are widely spaced, and the cohesive forces between them are very small. Unlike liquids, a gas in an open container cannot form a free surface.
Laminar flow: The highly ordered fluid motion characterized by smooth layers of fluid. The flow of high-viscosity fluids such as oils at low velocities is typically laminar in flow.
Project for engineering and school students.
In this project, you can find everything related to the concept of viscosity :- Definition, Derivation, Units, Kinematic viscosity. Newton's law of viscosity, variation of viscosity with temperature, types of fluids are also included. If you find it helpful to you, give some feedback.
Thank You very much :)
Computer Basics Presentation on airport authority of india guwahati with NITCONDipjyoti Deka
The presentation was the part of Skill Development program by NITCON on Airport Authority of India Guwahati, Airport road, Assam.
I as an instructor worked with NITCON to complete the mission of Skill Development in AAI Guwahati.
I hope People will get enough information regarding basics of Computer science that is necessary to survive in this 21st century.
Industrial training report on spray technicics, its various sheet metal opera...Dipjyoti Deka
Industrial/Internship/Project Report on Spray Technics, Ecotech III, GB nagar, Greater Noida, UP.
The report is the overall summary of what i have learnt during my 16 days internship.
From this report you may get an idea about an Sheet Metal Industry.
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
Vaccine management system project report documentation..pdfKamal Acharya
The Division of Vaccine and Immunization is facing increasing difficulty monitoring vaccines and other commodities distribution once they have been distributed from the national stores. With the introduction of new vaccines, more challenges have been anticipated with this additions posing serious threat to the already over strained vaccine supply chain system in Kenya.
COLLEGE BUS MANAGEMENT SYSTEM PROJECT REPORT.pdfKamal Acharya
The College Bus Management system is completely developed by Visual Basic .NET Version. The application is connect with most secured database language MS SQL Server. The application is develop by using best combination of front-end and back-end languages. The application is totally design like flat user interface. This flat user interface is more attractive user interface in 2017. The application is gives more important to the system functionality. The application is to manage the student’s details, driver’s details, bus details, bus route details, bus fees details and more. The application has only one unit for admin. The admin can manage the entire application. The admin can login into the application by using username and password of the admin. The application is develop for big and small colleges. It is more user friendly for non-computer person. Even they can easily learn how to manage the application within hours. The application is more secure by the admin. The system will give an effective output for the VB.Net and SQL Server given as input to the system. The compiled java program given as input to the system, after scanning the program will generate different reports. The application generates the report for users. The admin can view and download the report of the data. The application deliver the excel format reports. Because, excel formatted reports is very easy to understand the income and expense of the college bus. This application is mainly develop for windows operating system users. In 2017, 73% of people enterprises are using windows operating system. So the application will easily install for all the windows operating system users. The application-developed size is very low. The application consumes very low space in disk. Therefore, the user can allocate very minimum local disk space for this application.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSEDuvanRamosGarzon1
AIRCRAFT GENERAL
The Single Aisle is the most advanced family aircraft in service today, with fly-by-wire flight controls.
The A318, A319, A320 and A321 are twin-engine subsonic medium range aircraft.
The family offers a choice of engines
Event Management System Vb Net Project Report.pdfKamal Acharya
In present era, the scopes of information technology growing with a very fast .We do not see any are untouched from this industry. The scope of information technology has become wider includes: Business and industry. Household Business, Communication, Education, Entertainment, Science, Medicine, Engineering, Distance Learning, Weather Forecasting. Carrier Searching and so on.
My project named “Event Management System” is software that store and maintained all events coordinated in college. It also helpful to print related reports. My project will help to record the events coordinated by faculties with their Name, Event subject, date & details in an efficient & effective ways.
In my system we have to make a system by which a user can record all events coordinated by a particular faculty. In our proposed system some more featured are added which differs it from the existing system such as security.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
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Student information management system project report ii.pdf
Dynamic viscosity
1. Department of Mechanical Engineering
Don Bosco College of Engineering and
Technology, ADBU
By Dipjyoti Deka
1/18/2019 1
2. INTRODUCTION
The two aspects of fluid mechanics:-
1. The nature of a fluid is much different to that of solid.
2. In fluids, we usually deal with continuous streams of fluid without a beginning or end.
We normally recognize three states of matter: solid, liquid and gas. However, liquid and gas
are both fluids; in contrast to solids they lack the ability to deformation. Because a fluid
cannot resist the deformation force, it moves up, it flows under the action of the force.
Its shape will change continuously as ling as force is applied.
1/18/2019 2
3. The deformation is caused by shearing forces which act tangentially to a surface. As we
can see the force F acting tangentially on a rectangular element ABCD. This is a
shearing force and produces the rhombus element A’B'
A
D
B
B’
C
A’
Shearing force F, acting on the fluid element.
Hence, we can say that A fluid is a substance which deforms continuously when subjected
to shearing forces.
1/18/2019 3
4. VISCOSITY
A property of fluid to resist the rate of deformation- a quantitive measure of a fluid’s
resistance to flow (water v/s syrup). It takes place when a fluid is acted upon by a shear
stress.
It is an important fluid property when analyzing liquid behavior and fluid motion near
solid boundaries. The shear resistance in a fluid is caused by intermolecular friction
exerted when layers of fluid attempt to slide by one another.
There are two related measures of fluid viscosity:
• Dynamic or Absolute
• Kinematic
1/18/2019 4
5. Why does viscosity exist in fluid flow
1/18/2019 5
Molecular collisions – the molecules of the fluid bump into each other,
slowing down their motion
Momentum transfer from higher momentum to lower - momentum is mass
times velocity, mu. During a collision, momentum will be transferred.
Measured by shear stress τ,, which is the tangential force divided by the
area
6. Fluid with low viscosity Fluid with high viscosity
1/18/2019 6
7. Newton’s law of Viscosity
Viscosity is the physical property that characterizes the flow resistance of simple fluids.
Newton’s law of viscosity defines the relationship between the shear stress and shear rate of
a fluid subjected to a mechanical stress. The ratio of shear stress to shear rate is constant,
for a given temperature and pressure, and is defined as the viscosity or coefficient of
viscosity. Newtonian’s fluids obey Newton’s law of viscosity.
Thus, Viscosity is independent of the shear rate. Similarly, Non-Newtonian fluids do not
follow Newton’s law and thus, their viscosity (ratio of shear stress to shear rate) is not
constant and is dependent on the shear rate.
1/18/2019 7
8. Dynamic viscosity:- It is the tangential force per unit area required to move one
horizontal plane with respect to an other plane- at an unit velocity- when maintaining an
unit distance apart in the fluid. The shearing stress between the layers of a non-turbulent
fluid moving in straight parallel lines can be defined for a Newtonian Fluid as:
1/18/2019 8
9. Fig shows two fluid layers at distance y and y+dy from the surface. They move with different
velocities u and u+du as shown in fig. The top layer causes a shear stress on lower while lower
layer causes shear stress on the top layer. The shear stress τ is proportional to the rate of change
of velocity with respect y.
Mathematically, 𝜏α
𝑑𝑢
𝑑𝑦
𝜏 = μ
𝑑𝑢
𝑑𝑦
Here constant of proportionality μ is known as the coefficient of dynamic viscosity
𝑑𝑢
𝑑𝑦
known as
the velocity gradient.
From the above equation μ=
𝜏
𝑑𝑢
𝑑𝑦
1/18/2019 9
10. Causes of Viscosity in Fluids
1/18/2019 10
Viscosity in Gasses
The molecules of gasses are only weakly kept in position by molecular cohesion (as they
are so far apart). As adjacent layers move by each other there is a continuous exchange of
molecules. Molecules of a slower layer move to faster layers causing a drag, while
molecules moving the other way exert an acceleration force. Mathematical considerations
of this momentum exchange can lead to Newton law of viscosity.
If temperature of a gas increases the momentum exchange between layers will
increase thus increasing viscosity.
Viscosity will also change with pressure - but under normal conditions this change
is negligible in gasses.
12. Viscosity in Liquids
There is some molecular interchange between adjacent layers in liquids - but as the
molecules are so much closer than in gasses the cohesive forces hold the molecules in place
much more rigidly. This cohesion plays an important roll in the viscosity of liquids.
Increasing the temperature of a fluid reduces the cohesive forces and increases the molecular
interchange. Reducing cohesive forces reduces shear stress, while increasing molecular
interchange increases shear stress. Because of this complex interrelation the effect of
temperature on viscosity has something of the
form:
where is the viscosity at temperature T°C, and is the viscosity at temperature 0°C. A
and B are constants for a particular fluid.
High pressure can also change the viscosity of a liquid. As pressure increases the relative
movement of molecules requires more energy hence viscosity increases.
1/18/2019 12
14. Viscosity Measurements
• These viscometer give the value of the ‘dynamic viscosity’.
• It is based on the principle that the fluid whose viscosity is being measured is sheared
between two surfaces.
• In these viscometers one of the surfaces is stationary and the other is rotated by an external
drive and the fluid fills the space in between.
• The measurements are conducted by applying either a constant torque and measuring the
changes in the speed of rotation or applying a constant speed and measuring the changes in
the torque.
• There are two main types of these viscometers: rotating cylinder and cone-on-plate
viscometers.
1/18/2019 14
17. Fluid flow between two parallel plates
The bottom plate is fixed and the top plate is accelerated by applying
some force that acts from left to right.
The upper plate will be accelerated to some terminal velocity and the
fluid between the plates will be set into motion.
Terminal velocity is achieved when the applied force is balanced by a
resisting force (shown as an equal but opposite force applied by the
stationary bottom plate).
1/18/2019 17
18. As the upper plate begins to accelerate the velocity of the fluid molecules
in contact with the plate is equal to the velocity of the plate (a no slip
condition exists between the plate and the fluid).
Fluid molecules in contact with those against the plate will be
accelerated due to the viscous attraction between them... and so on
through the column of fluid.
The viscosity of the fluid ( , is the attraction between fluid molecules)
results in layers of fluid that are increasingly further from the moving
plate being set into motion.
1/18/2019 18
19. The velocity gradient (the rate of change in velocity between plates;
du/dy) will be constant and the velocity will increase linearly from zero
at the bottom plate to Uterm at the top plate.
Terminal velocity is achieved when the resisting force (the force shown
applied by the bottom plate) is equal but opposite to the force applied to
the top plate (forces are equal so that there is no change in velocity with
time).
The bottom plate and water molecules attached to it are stationary (zero
velocity; no slip between molecules of fluid and the plate) so that
eventually the velocity will vary from zero at the bottom to Uterm at the
top which is equal to the terminal velocity of the upper plate.
1/18/2019 19
22. Effect of viscosity on velocity profile
1/18/2019 22
Fluid flow is highly dependent on the viscosity of fluids. At the same time for a non-Newtonian
fluid, the viscosity is determined by the flow characteristics . Looking at Figure , we can
observe three very different velocity profiles depending on the fluid behavior. For all these
fluids, the shear rate at the walls (i.e. the slope of the velocity profile near the wall) is going to
determine viscosity. Successful characterization of viscosity is key in determining if a fluid is
Newtonian or non-Newtonian, and what range of shear rates needs to be considered for an
specific application.
23. Several fundamental effects are produced by viscosity:
1/18/2019 23
Drag: Skin friction drag caused by shear stresses at the surface contribute a majority of
the drag of most airplanes.
The pressure distribution: is changed by the presence of a boundary layer, even when no
significant separation is present.
Flow separation: Viscosity is responsible for flow separation which causes major
changes to the flow patterns and pressures.
24. 1/18/2019 24
Viscosity and Navier–Stokes equations
The Navier–Stokes equations, describe the motion of viscous fluid substances. These
balance equations arise from applying Newton's second law to fluid motion, together with the
assumption that the stress in the fluid is the sum of a diffusing viscous term and a pressure
term—hence describing viscous flow.
Viscosity and Coutette’s flow
Couette flow is the laminar flow of a viscous fluid in the space between two parallel plates,
one of which is moving relative to the other. The flow is driven by virtue of viscous drag
force acting on the fluid and the applied pressure gradient parallel to the plates.
25. Viscosity Effects In Dynamic Light Scattering Measurements
1/18/2019 25
• Dynamic light scattering (DLS) is a method for monitoring crystallization processes, solutions.
• DLS measures how fast the particles diffuse through the liquid.
• Smaller particles diffuse faster than larger ones.
• Solvent viscosity effect the measurement.
• For precise determination of particle size, it is essential to know the exact viscosity value of
the solvent.