Lab Report-osborne Reynolds Experiment

CE 291 FLUID MECHANICS LABORATORY

Osborne Reynolds Experiment

Submitted by

RAVI KIRAN 1801CE27

DEPARTMENT OF CIVIL AND ENVIRONMENTAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY PATNA JUL-NOV 2019

TABLE OF CONTENTS

LIST OF FIGURES………………………………………………………………

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LIST OF TABLES………………………………………………………………..

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TITLE OF THE EXPERIMENT ABSTRACT………………………………………………………………………..

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INTRODUCTION………………………………………………………………….

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METHODS AND MATERIALS……………………………………......................

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DATA AND OBSERVATIONS…………………………………………………...

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CALCULTION..........................................................................................................

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CONCLUSION AND DISCUSSION……………………………………………...

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REFERENCES……………………………………………………………………..

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LIST OF FIGURES

FIGURE NO.

TOPIC

PAGE

Figure 1

Flow characteristics

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Figure 2

Unit description

5

Figure 3

Observed flow pattern

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2

LIST OF TABLES

S.NO.

Table 1

HEADING

Observed Values

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PAGE

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OSBORNE REYNOLDS EXPERIMENT ABSTRACT 1. Title: To demonstrate Osborne Reynolds Experiment for a given flow of water. 2. Objective: To check the type of flow pattern, whether it is turbulent flow, transition flow, or laminar flow and to find corresponding Reynolds number. 3. Methods: Firstly, put the ink in the aluminium reservoir with no water supply through inlet tube. Now allow water to get in the tube, and adjust the control valve and drain valve simultaneously such that water level remains constant in water tank, and thus get required flow pattern. 4. Results: Reynolds number for this experiment is 149044 which is greater than 2300, so flow pattern for this observation is Turbulent flow.

1. INTRODUCTION Laminar flow(Re < 2300) is "orderly". The flow of a fluid, when each particle of the fluid follows a smooth path, paths which never interfere with one another. The velocity of the fluid is constant at any point in the fluid. It occurs at low flow rate. Turbulent flow(Re > 2300) is "Random". Irregular flow that is characterized by tiny whirlpool regions. The velocity of this fluid is not constant at every point. It occurs at high flow rate. Transitional flow(Re is approximately 2300). is a mixture of laminar and turbulent flow, with turbulence in the center of the pipe, and laminar flow near the edges.

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Figure 1: Flow characteristics (Source:-http://www mdp.eng.cam.ac.uk/web/library/enginfo/aerothermal_dvd_only/aero/fprops/pipeflow/no de8.html) 2. METHODS AND MATERIALS Materials : Water, Dye, Stop Watch, and Unit Description for Osborne Reynolds Demonstration.

Figure 2: Unit description (Source: Lab manual) Methodology: Water is allowed to enter through water supply nozzle in to water tank, and then flow is adjusted using “Control valve and Drain valve” in such a that water level in water tank is almost constant (Neither rise nor fall). Now, Metering tap of ink reservoir is opened and ink flows through Test pipe section. Now without disturbing the flow rate, we measure its volume flow rate, through drain valve using stop watch and measuring tank. Then, we measure volume flow rate of inlet water through water supply nozzle using stop watch and measuring tank. 5

Reynolds number formula:➢ 𝑅𝑒 =

𝑤.𝑑 Ʋ

where; d

w = Flow rate in m/s. = Inner diameter of test pipe section in m.

Ʋ = Kinematic viscosity of the medium in m^2/s. ( Water: Ʋ = 1×10^(-6)m^2/s ) Flow rate(w) can be calculated from volume flow rate, 𝑤=

𝑣𝑜𝑙𝑢𝑚𝑒 𝑓𝑙𝑜𝑤 𝑟𝑎𝑡𝑒(𝛷) 𝐴𝑟𝑒𝑎(𝐴)

Where: 𝛷=

𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑤𝑎𝑡𝑒𝑟, 𝑣 𝑇𝑖𝑚𝑒(𝑡)

𝐴 = 𝜋𝑟 2 = 7.85×10^-5 m^2. r (Radius of test pipe section) = 5 mm 3. DATA AND OBSERVATIONS Table 1: Observed values s.no

1.(INLET)

2.(OUTLET)

Volume,v (m^3)

Time,t (s)

Volume Flow rate,Φ (m^3/s)

0.02

16.41

1.21×10^-3

0.001

27.17

3.68×10^-5

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➢ Our observed flow pattern for above Readings is like this:--

Figure 3:-Observed Flow Pattern (Turbulent flow)

4. CALCULATION Volume Flow rate through testing pipe section = Φ(inlet) – Φ(outlet) = 1.17×10^-3 m^3/s. So, 1.17×10−3

Flow rate,𝑤 = 7.85×10−5 = 14.9044 m/s.

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So, Reynolds no. ,𝑹𝒆 =

𝟏𝟒.𝟗𝟎𝟒𝟒×𝟎.𝟎𝟏 𝟏×𝟏𝟎−𝟔

= 149044 Which is more than 2300, so flow is Turbulent Flow 5. CONCLUSION AND DISCUSSION Reynolds number for above observation is 149044 which is greater than 2300, so

flow

pattern for above experiment is Turbulent flow. It implies that the velocity of this fluid is not constant at every point, The movement of fluid particles is chaotic. It also implies that flow has higher velocity and fluid had low viscosity. In this experiment, we observed that the blue dye line change with the increasing of water flow rate. The shape change from thin threads to slightly swirling which still contains smooth thin threads and then fully swirling. We can say that this change is from laminar flow to transitional flow and then to turbulent flow and it is not occuring suddenly. We must control the water inlet valve and outlet valve until the flow formed. 6. REFERENCES 1. Lab Manual(Osborne Reynolds Demonstrator) 2. Aerospace, Mechanical & Mechatronic Engg. 2005 University of Sydney, Classification of Flows,

Laminar

and

Turbulent

Flows(http://www

mdp.eng.cam.ac.uk/web/library/enginfo/aerothermal_dvd_only/aero/fprops/pipeflow/no de8.html)

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