AERODYNAMICS LAB MANUAL (PCT)

Department of Aeronautics AE2258 2

AERODYNAMICS LABORATORY

003

LIST OF EXPERIMENTS 1. Generation of lift and tip vortices. 2. Flow visualization in water flow channel. 3. Flow visualization in smoke tunnel. 4. Plot of RPM Vs test section velocity in a subsonic wind tunnel. 5. Pressure distribution over circular cylinder. 6.

Pressure distribution over airfoil and estimation of and

.

7. Force measurement using wind tunnel balance. 8. Mach number distribution in nozzle of supersonic wind tunnel. 9. Use of Schlieren system to visualize shock. 10.Use of Shadow graph system to visualize shock.

Ex.no: 01

STUDY OF SUBSONIC WIND TUNNEL

INTRODUCTION Wind tunnels are devices which provides air streams flowing under controlled conditions so that models of interest can be tested using them from operational point of view , wind- tunnels are generally classified as (1) Low speed tunnels (2) High speed tunnels (3) Specific purpose tunnels. LOW SPEED TUNNELS Low speed tunnels are those with test section speed less than 650kmph depending upon the test section size. They are referred to as small size (or) fuel scale tunnels , having no guide return of air as shown in fig,. After leaving the diffuser , the air circulates , by division path back to the intake , if the tunnel , draws air density from the atm entirely fresh air is used . The second type , called closed circuit tunnels (or) return flow tunnel , has a continuous path of the air. Both open circuit and closed circuit tunnels can operate with either open jet (or) closed jet is that test sections. Open jet is that test section without side walls .The test section cross section can have different sidewalls and closed jet is that with sidewalls. The cross section can have different shapes such as rectangular , circular , elliptical , octagonal etc,. A generally utility low speed tunnel has flow important components namely , the diffuser , the test-section , the diffuser and driving unit. n=

Area of entry of convergent curve Area of exit of convergent curve

The contraction ratio usually varies from 4 to 20 for conventional low speed tunnel. TEST SECTION The portion of the tunnel with constant flow characteristics , across its section is tunnel as test or working section , since , boundary layer is formed along the test section walls . The walls are given a suitable divergence so that the net cross sectional area of the uniform flow is constant along the length of test section .

DIFFUSER The purpose of the diffuser is to convert the kinetic energy of the flow coming out of the test section of the pressure energy. Before it leaves the diffuser , as efficiently as possible generally. The smaller is the diffuser near the exit , its cross section should be circular to commodate the fan.

THE DRIVING UNIT Generally the drive which consists of a motor and a propeller (or) fan combination. The fan is to increases the static pressure of the stream leaving the diffuser. The wind tunnel fan working similar to the propeller of airplane operates under peculiar conditions that put it in a class by itself . since the thrust of the fan is drag of various tunnel companents vary they maintain an even velocity front in test section. Although the conclusion is not true. In deed many large tunnels which are equipped with both rpm and pitch change mechanism use only the lather being quick and similear.

RESULTS The subsonic wind tunnel is studied.

Ex.no:02

FORCE MEASUREMENTS USING SYMMETRIC AIRFOIL

AIM To measure the viscous force using symmetric airfoil at different angle of attack . APPARATUS REQUIRED Subsonic wind tunnels Symmetric airfoil PROCEDURE 1. Switch ON the power supply and then take on the console. 2. Warm up the tunnel for about 10 min to obtain accurate values. 3. By turning the AC motor, adjust the speed of the air speed indicator. 4. Which is required few our experiments. 5. Place the symmetrical airfoil at 0’ angle of attack. 6. Note down the corresponding values of forces for the angle of attack. 7. Change the angle of attack to 5°,10°,15° and note the values of forces for the angle of attack. 8. For different angle of attack, follow the same procedure. 9. Tabulate the readings and calculate 10.Plots the graph by using FORMULA

= ρA

/2g × 1/

,

,

,

,

for each angle of attack.

and to the angle of attack.

Where, α = angle ρ = 1.29 kg/ g= 9.81 m A= S×C ,

,

=

/

Force measurement using symmetric airfoil S.no

Angle of attack

Velocity (m/s)

Lift force (kg)

Drag force (kg)

Side force (kg)

RESULT Thus the

Ex.no:03

,

,

on symmetrical airfoil at different angle of attack is determined.

PRESSURE DISTRIBUTION OF CIRCULAR CYLINDER

AIM To determine the pressure distribution over a circular cylinder APPARATUS REQUIRED Cylindrical pattern Subsonic, wind tunnel Pressure distribution tube Control unit of wind tunnel FORMULA Coefficient of pressure =Initial pressure =Final pressure =coefficient of pressure PROCEDURE

=

1. The pressure tube are connected to the circular cylinder to be fixed in the visualization part. 2. To start the tunnel to measure the pressure in various of the cylinders. 3. To set the air velocity of constant and set the cylinder is zero angle of attack, next rotated to another hole step by step. 4. To measure the distribution of all pressure tubes are to be noted the increasing and decreasing values. 5. Then calculated the noted value by using the formula. 6. Draw a graph by using a calculated value in x-axis as angle of attack and in y-axis pressure distribution.

TABULATION Pressure distribution of circular cylinder Position of point in the direction of flow

Position of points on the cylinder

1

2

3

4

5

6

7

8

9

Reference mano-meter

10

11

12

RESULT Then the determination of the pressure distribution over a circular cylinder are estimated. Ex.no:04

PRESSURE DISTRIBUTIONS OVER A SYMMETRIC AIRFOIL

AIM To determine the Pressure Co-efficient on Symmetric Airfoil at different values of angles of attack. APPARATUS REQUIRED Subsonic wind tunnel Pressure distribution tube Symmetric airfoil FORMULA

=

/ -P

Where, = = static pressure in cm [from Manometer 13th point] = pressure at each point in cm

-P = initial Manometer reading in cm

PROCEDURE 1. Initially switch ON the power supply and then the renside is one condition. 2. Warm up the subsonic wind tunnel for about 10 minutes in order to obtain the accurate values. 3. By turning the AC motor adjust the speed of the air in the air speed indicator, which is required for our experiments. 4. Place the symmetric airfoil in zero angle of attack and then note the corresponding values of locations 1 to 13 in pressure distribution tubes. 5. Change the airfoil the angle of 5° and then again note the corresponding values in the pressure distribution tubes. 6. Follow the same procedure for different angles in the symmetric airfoil. 7. Tabulate the readings and calculate pressure for each angles. 8. Plot the graph by using the pressure distribution on symmetric airfoil to the pressure in mm of water.

Value of pressure co-efficient on symmetrical airfoil S. no

Locations

Angle of attack in degree [Initial Manometer Reading =6cm] 0

5

10

15

-5

-10

-15

RESULT Thus the pressure distribution over symmetric airfoil is calculated. Ex.no:05

PRESSURE DISTRUBTION OVER UNSYMMETRIC AIRFOIL

AIM To determine the pressure co-efficient of unsymmetrical airfoil at different values of angle of attack.

APPARATUS REQUIRED Subsonic wind tunnel Pressure distribution tube Unsymmetrical airfoil FORMULA

=

/ -P

Where, = = static pressure in cm [from Manometer 13th point] = pressure at each point in cm -P = initial Manometer reading in cm PROCEDURE 1. Initially switch ON the power and then turn the consider is one condition. 2. Warm up the subsonic wind tunnel for about 10 minutes in order to obtain the indicator which is required for our experiments. 3. By turning the AC motor adjust the speed of the air in the air speed of the air in the air speed indicator which is required for our experiments. 4. Place the un-symmetric airfoil in zero angle of attack and then note the corresponding values in locations 1 to 13 in pressure distribution tubes. 5. Change the airfoil angle to 5° and then again note the corresponding values in the pressure distribution tubes. 6. Follow the same procedure for different angle in the un-symmetric airfoil. 7. Tabulate the reading and calculate pressure for each angle. 8. Plot the graph by using the pressure distribution for each angle on un-symmetric airfoil to the pressure in mm of water.

Values of pressure co-efficient on un-symmetrical airfoil

S. no

Locations

Angle of attack in degree [Initial Manometer Reading =6.5cm] 0

5

10

15

-5

RESULT Thus the pressure distribution over un-symmetric airfoil is calculated. Ex.no:06

FLOW VISUALIZATION USING WATER CHANNEL

-10

-15

AIM To visualization the flow using water flow channel by using two dimensional object. APPARATUS REQUIRED Water flow channel Two dimensional surfaces PROCEDURE 1. Two dimensional models are kept in text section is made visible by placing silver threads the water channels is well studied for the study the effect of models on the flow pattern. 2. When kept in a stream line flow the following models are used for flow visualization. (1) Water flow channel and (2) two dimensional surfaces. 3. Laminar flow of water in a channel is in flow condition. 4. For above condition operate the variable drive in clockwise direction. 5. Observe the condition of flow should be dominant. 6. In the middle floe path keep the model (Airfoil, Square, and Triangle) one at a time. 7. The silver threads are called place [called Al, powder] in path of water flow and model the silver threads travels in directions of flow and passes through the model closely observe the pattern formed around the model. It can be photographed. 8. The equipment is made of strain less factor tory in which contact portions are made for flow path. 9. The flow path length –‘6’. 10.Width of channel is two sideways ‘6’. 11.Width o channel in center ‘a’. 12. Curved blade at entry and the other end is made for smooth flow. 13. The curve blades can be removable type on the other end for different condition. 14. A common shaft is connected by belt to DC digital motor. 15. The RPM of motor can be read in digital meter. 16. Once the experiment is completed drain the water. 17. The water height in channels should not be more than 2 ½ in height from base flow.

RESULT Thus the flow can be visualized. Ex.no:07

SMOKE FLOW VISUALAIZATION

AIM To find characteristics of this flow generated by given objects. APPARATUS REQUIRED Airfoil (or) the plate buff bodies THEORY 1. The most common method of flow field visualization is sum significate advantages of system is fact that smoke can be started and stopped in fraction at a second whish is not true of alternate this allows the problem associated photographic record rather than real time human visual inspection. 2. Filament can be used to final key location such as stagnation points, so can easily shoe the extent of separated regions and the size of separate bubble smoke can be used to show the track strong surface features. 3. Such a tip or leading edge verticals from lifting surface that may impinge and downstream regions of separated flow wake bubbles and its extent can be analyzed easily. 4. The smoke generated unit is used for producing the dance smoke for purpose of flow visualization across model, essentially its concept of electrical cartridge heat over the diesel bottle. Sump bottles, air supply from blower of demote and smoke distribution. PROCEDURE 1. Cover the back side of test section with dark cloth. 2. Switch ON the light. 3. Keep the needle value closed. 4. Fill the overhead bottle with diesel and check level. 5. Connect the electrical supply of cartridge heated to control panel.

6. Fix the require model is test section (or) orientation. 7. Connect the air inlet and smoke generation to the outlet. 8. Initially open the needle value and allow the diesel. 9. Now switch ON the neater control unit and keep out it minimum. 10. After the initial heating is done the smoke starts coming out of smoke distribution now decrease the heating and diesel tip in much a way that continuous sonic smoke starts coming out of distribution. 11. Switch ON the DC motor controlled and it to XY the fan. 12. Adjust the sapped to get uniform visible smoke and airfoil model higher velocity will diffuse the smoke. 13. The used diesel controller in the sump bottle and outlet smoke pipes may be put back over heat bottle. 14. The observe the flow pattern at different orientation of models. 15. After the experiment is over of the heat controller close the needle value and switch off the light. 16. Allow the flow blower and fan to operate the far sometime to drive unused smoke. CAUTIONS 1. During experimental check for blockage due to condensed oils in smoke outlet leading to distribution and drain onto sump bottle. 2. Check periodically that adequate amount of diesel oil is available in the over neat bottle. 3. Never switch ON the heater for long time the diesel oil being supply to unit.

CONCLUSION Thus the flow fields around the given model of different orientation were analyzed using smoke flow visualization. The flow fields are sketched manually and in some occasions photographed for future analyses. Ex.no:08

GENERATION OF LIFT AND TIP VORTICS

AIM To find the characteristics the flow fluid generated by given objects. APPARATUS REQUIED Airfoil (or) flat buff bodies THEORY 1. The most common method of flow field visualization is sum subjected significant advantage of system is fact that smoke can be started and stopped in fractionate second which is not true of alternative. This allows the problems associated which to be maintained photographic record rather than real time human visual inspection can be per amount. 2. Filament can be used to find key locations such as stagnation points so can bubble smoke can be used to show the track strong surface features. 3. Such a tip or leading edge verticals from lifting surfaces that may impinge and downstream regions of separated flow wake bubbles and its extent can be analyzed easily.

4. The smoke generated unit is used for producing the dence smoke for purpose of flow visualization across model. Essentially its concept of electrical cartridge heat over the diesel bottle, sump bottle , air supply from blower of demote and smoke distribution. PROCEDURE 1. Cover the back side of test section with dark cloth. 2. Switch ON the light. 3. Keep the needle value closed. 4. Fill the overhead bottle with diesel and check level. 5. Connect the electrical supply of cartridge heated to control panel. 6. Fix the require model is test section (or) orientation. 7. Connect the air inlet and smoke generation to the outlet. 8. Initially open the needle value and allow the diesel. 9. Now switch ON the neater control unit and keep out it minimum. 10. After the initial heating is done the smoke starts coming out of smoke distribution now decrease the heating and diesel tip in much a way that continuous sonic smoke starts coming out of distribution. 11. Switch ON the DC motor controlled and it to XY the fan. 12. Adjust the sapped to get uniform visible smoke and airfoil model higher velocity will diffuse the smoke. 13. The used diesel controller in the sump bottle and outlet smoke pipes may be put back over heat bottle. 14. The observe the flow pattern at different orientation of models. 15. After the experiment is over of the heat controller close the needle value and switch off the light. 16. Allow the flow blower and fan to operate the far sometime to drive unused smoke. CAUTIONS 1. During experimental check for blockage due to condensed oils in smoke outlet leading to distribution and drain onto sump bottle. 2. Check periodically that adequate amount of diesel oil is available in the over neat bottle. 3. Never switch ON the heater for long time the diesel oil being supply to unit.

CONCLUSION Thus the flow fields around the given model of different orientation were analyzed using smoke flow visualization. The flow fields are sketched manually and in occasions photographed for future analyses. Ex.no:09

USE OF SCHLIEREN SYSTEM TO VISUALIZE SHOCK

AIM To study about use of Schlieren system to visualize shock. APPARATUS REQUIRED

Recording device Mirror Test section Light source Model PROCEDURE 1. During a test, the model is placed on test section of tunnel of air is made to flow part the model. 2. In some wind tunnel tests flow visualization techniques are used to produces and provide diagnostic information about the models. 3. The older flow visualization techniques are Schlieren photography. 4. Schlieren systems to visualization the flow away from surfaces. 5. It uses the two objects concave mirrors on either sides of test section of wind tunnel. 6. A mercury vapour lamp (or) spark gap system that the reflected light from the mirror from the parallel rays. 7. The ray’s continuous and recording device. 8. Now parallel rays of light encounter density gradient in test section light is bent. 9. The shock waves are produced by model soon as dark lines on image. 10.The Schlieren photography provides some valuable information about location and strength of shock waves.

RESULT Thus Schlieren system to visualize shock is studied.

PARK COLLEGE OF TECHNOLOGY

KARUMATHAMPATTI, COIMBATORE

AERODYNAMICS LABORATORY MANUAL

SUBJECT CODE : AE 2258 YEAR/SEM

: II/IV

DEPARTMENT OF AERONAUTICAL ENGINEERING

ANNA UNIVERSITY::CHENNAI-25

REGULATION 2008

DATE: 02-01-2013

S.NO

APPROVED BY

LIST OF EXPRIMENTS

PAGE NO

01

STUDY OF SUBSONIC WIND TUNNEL

02

FORCE MEASUREMENTS USING SYMMETRIC AIRFOIL

03

PRESSURE DISTRIBUTION OF CIRCULAR CYLINDER

04

PRESSURE DISTRIBUTIONS OVER A SYMMETRIC AIRFOIL

05

PRESSURE DISTRUBTION OVER UNSYMMETRIC AIRFOIL

06

FLOW VISUALIZATION USING WATER CHANNEL

07

SMOKE FLOW VISUALAIZATION

08

GENERATION OF LIFT AND TIP VORTICS

09

USE OF SCHLIEREN SYSTEM TO VISUALIZE SHOCK

STAFF INCHARGE