Laminar and turbulent flow can be distinguished by observing dye injected into a flowing fluid. Laminar flow moves in parallel, undisrupted layers while turbulent flow is disorganized with eddies. The Reynolds number determines whether flow is laminar or turbulent based on velocity, diameter, density and viscosity. Laminar flow has Re ≤ 2000 while turbulent flow has Re ≥ 3000. Viscosity resists flow and decreases with temperature for liquids but increases for gases.
Differential Boundary-Layer Analysis and Runback Water Flow Model Applied to ...ATS4i
The present work implemented heat transfer sub-models into an anti-ice
model to:
1) estimate the airfoil surface wetness factor by adopting a liquid water
film flow model as well as a rivulet formation and flow model;
2) evaluate laminar and turbulent boundary layers with pressure gradient
and laminar-turbulent transition over non-isothermal and permeable
airfoil surfaces by implementing differential boundary layer analysis
and
3) predict the onset position and length of the laminar-turbulent transition
region.
Fluid Mechanics-Shear stress ,Shear stress distribution,Velocity profile,Flow Of Viscous Fluid Through The circular pipe ,Velocity profile for turbulent flow Boundary layer buildup in pipe,Velocity Distributions
Fluid Flow, Heat and Mass Transfer at Bodies of Different Shapes: Numerical Solutions presents the current theoretical developments of boundary layer theory, a branch of transport phenomena. Also, the book addresses the theoretical developments in the area and presents a number of physical problems that have been solved by analytical or numerical method. It is focused particularly on fluid flow problems governed by nonlinear differential equations. The book is intended for researchers in applied mathematics, physics, mechanics and engineering.
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.
a presentation about Reynolds Number prepared by a group for the course of soil mechanics and was presented to Dr. Mohamed El-Taher. PS we did not create slide no. 17 and don't know its main source
4) What is the Reynolds number- Give an equation but also an explanati.docxtodd621
4) What is the Reynolds number? Give an equation but also an explanation of what is being compared. Give two situations where the Reynolds number is used
Solution
The Reynolds number (Re) is a dimensionless number related to fluid mechanics. It is among the most important attributes used for summarizing the forces acting on a fluid and, based on its value, the turbulence or lack of turbulence of a fluid is determined. The designation is named for Osborne Reynolds, who made many pioneering studies in fluid mechanics in the late 19th and early 20th centuries. The variations in the quantity are laid out on the X-axis of the Moody Chart, one of the more useful graphs in fluid mechanics.
More specifically, the Reynolds number is defined as the ratio of inertial forces, which contribute to turbulence, to viscous forces, which act against turbulence, within a fluid. Put another way, the number describes how likely flow is to be laminar or turbulent for a given set of physical conditions. Laminar, or smooth, flow indicates that everything in the flow of a fluid is moving in the same direction and these internal flows do not affect one another. Turbulent flow, on the other hand, indicates that disruptions or eddies are created within the main flow.
The most common example of laminar and turbulent flow can be found at a sink. When the water is first turned on and is not flowing very fast, it is clear. Most of the internal flows of the water do not interact with one another and move in the same direction; this is laminar flow and indicates a low Reynolds number. As the amount and speed of the water increases, it turns white. The internal flows begin to collide with one another in a turbulent flow, introducing air into the water stream.
Another example of the concept is to imagine an object moving through a fluid. The faster the object moves, the denser the liquid, and the more time the object moves, the more likely the fluid flow is to be turbulent. The more viscous or sticky a fluid is, the greater the chance the fluid
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1. Title: LAMINAR AND TURBULENT FLOW
BACKGROUND:
A flow can be Laminar, Turbulent or Transitional in nature. This becomes a very important
classification of flows and is brought out vividly by the experiment conducted by Osborne
Reynolds (1842 - 1912). Into a flow through a glass tube he injected a dye to observe the
nature of flow. When the speeds were small the flow seemed to follow a straight line path
(with a slight blurring due to dye diffusion). As the flow speed was increased the dye
fluctuates and one observes intermittent bursts. As the flow speed is further increased the
dye is blurred and seems to fill the entire pipe. These are what we call Laminar,
Transitional and Turbulent Flows.
Laminar flow:
Smooth, steady and orderly flow of fluid in a tube.
All the fluid molecules move in straight line.
Therefore they move parallel layers or laminae with no disruption between the layers.
Velocity of flow is greatest in the axial stream (center of the tube). It becomes
progressively slower as the layers move to the periphery.
Axial stream velocity is twice the mean flow velocity.
Velocity of the layer in contact with the wall is virtually zero.
Turbulent flow:
Fluid does not move in orderly manner.
The fluid molecules become more disorganized.
They form swirls and eddies as they move down the pressure gradient in haphazard
manner.
There is increased resistance to flow as the eddy currents interfere with each other.
Therefore greater energy is required for a given flow rate compared to when the flow
is laminar.
2. Reynolds Number, Re:
Reynolds number is a dimensionless parameter which determines whether the flow in a
closed conduit or a pipeline is laminar or turbulent.
Where: D = inside diameter of the pipe, m
= liquid velocity, m/s
= density of the fluid, kg/m3
= dynamic viscosity, Pa-s or Poise
Note: 1 poise = 1 = 0.1 Pa-s
If the dynamic viscosity is divided by the density, kinematic viscosity, v can be obtained:
V = . Therefore:
Where: V = kinematic viscosity, m2/s
Note: 1 stroke = 1 cm2/sec
Values of kinematic viscosity of various fluids can be determined from page
116 of Mechanical Engineering Tables and Charts SI units 5th Edition MRII.
If Re ≥ 3000 the flow is turbulent
Re ≤ 2000 the flow is said to be laminar
Viscosity
Viscosity is the property of a fluid that causes it to resist flow.
Viscosity of a liquid decreases with increased temperature, while viscosity of a gas increases
with increased temperature.
EQUIPMENTS:
1. Hydraulic Bench
2. Laminar and Turbulent Apparatus
