Department of Aeronautics AE2258 2
AERODYNAMICS LABORATORY
003
LIST OF EXPERIMENTS EXPERIMENTS 1. Generation of of lift and tip vortices. 2. Flow visualization visualization in water flow flow channel. 3. Flow visualization visualization in smoke smoke tunnel. tunnel. 4. Plot of RPM Vs test section section velocity in a subsonic wind tunnel. 5. Pressure distribution distribution over circular circular cylinder. 6.
Pressure distribution over airfoil and estimation of and
.
7. Force measurement measurement using wind wind tunnel balance. 8. Mach number distribution distribution in nozzle of supersonic supersonic wind tunnel. 9. Use of Schlieren Schlieren system to visualize visualize shock. 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 p rovides 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 speed tunne tunnels ls (2) High High speed speed tunnels tunnels (3) Specific Specific purpose purpose tunnels 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. sections. Open jet is that test section without side walls .The test section cross section can have different d ifferent sidewalls and closed jet is that with sidewalls. The cross section can have different shapes such as rectangular , circular , elliptical , octagonal o ctagonal etc,. A generally utility low speed tunnel has flow important components namely , the diffuser , the test-section , the diffuser and driving unit. n=
Area Area of ent entry of conv conver erge gent nt cur 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 w ith constant flow characteristics , across its section is tunnel as test or working section , since , boundary b oundary 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 con vert 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 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 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 x.no:0 :02 2
FOR FORCE MEA MEASURE SUREME MENT NTS S USI USIN NG SY SYMME MMETRIC TRIC AIRFO IRFOIL IL
AIM To measure the viscous force using symmetric airfoil at different angle of attack . APPARATUS REQUIRED Subsonic wind tunnels Symmetric airfoil PROCEDURE 1. Switch Switch ON the power power supply supply and and then then take take on the the console console.. 2. Warm up the tunnel tunnel for for about about 10 min min to obtain obtain accurat accuratee values. values. 3. By turning turning the the AC motor, motor, adjust adjust the the speed speed of the the air speed speed indic indicator. ator. 4. Which Which is requir required ed few few our our experi experimen ments. ts. 5. Place the symmetrica symmetricall airfoil airfoil at 0’ angle angle of attack. attack. 6. Note down down the corres correspond ponding ing values values of forces forces for for the angle angle of attack. attack.
7. Change the angle of attack to 5°,10°,15° and note the values of forces for the angle of attack. 8. For differe different nt angle angle of of attack, attack, follow follow the same same procedu procedure. re.
9. Tabu Tabula late te the the read readin ings gs and and calc calcul ulat atee Plotss the the grap graph h by usin using g 10. Plot FORMULA
= ρA
/2g × 1/
,
,
,
,
for for each each angl anglee of atta attack ck..
and and to the the angl anglee of atta attack ck..
Where, α = angle ρ = 1.29 kg/ g= 9.81 m A= S×C ,
,
=
/
Force measurement using symmetric airfoil
S.no
Angle Velocity of attack (m/s)
Lift force (kg)
Drag force (kg)
Side force (kg)
RESULT Thus Thus the the
Ex.no:03
,
,
on symm symmet etric rical al airfo airfoil il at diffe differe rent nt angl anglee of atta attack ck is dete determ rmin ined ed..
PRESSURE DISTRIBUTION OF CIRCULAR CYLINDER
AIM To determine the pressure distribution over a circular c ylinder 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 pressure tube tube are connected connected to the the circular circular cylinder cylinder to be fixed fixed in the visualiz visualization ation part. part. 2. To start start the tunnel tunnel to measur measuree the pressure pressure in variou variouss of the cylind cylinders. ers. 3. To set the air air velocity velocity of constant constant and and set the cylind cylinder er is zero angle angle of attack, attack, next rotated rotated to another hole step by step. 4. To measure measure the distribu distribution tion of all all pressure pressure tubes are to to be noted the the increasing increasing and and decreasing decreasing values. 5. Then calculated calculated the noted noted value value by using using the the formu formula. la. 6. Draw a graph graph by using using a calculated calculated value value in x-axis x-axis as angle angle of attack and and in y-axis y-axis pressure pressure distribution.
TABULATION Pressure distribution of circular c ylinder
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 11
12
RESULT Then the determination of the pressure distribution over a circular cylinder are estimated. Ex.no x.no:0 :04 4
PRES PRESSU SUR RE DIS DISTR TRIB IBU UTIO TIONS OVER VER A SY SYMME MMETRIC TRIC AIRFO IRFOIL IL
AIM To determine the Pressure Co-efficient 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 static pres pressur suree in cm [fro [from m Manom Manomete eterr 13th point] = pressure at each point in cm
-P = initial Manometer reading in cm
PROCEDURE 1. Initially Initially switch switch ON the power power supply supply and and then the the renside renside is one one condition condition.. 2. Warm up the subson subsonic ic wind tunnel tunnel for for about 10 minute minutess in order to obtain obtain the accurat accuratee values. values. 3. By turning turning the AC motor motor adjust adjust the speed speed of the air in the the air speed speed indicator, indicator, which which is required 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 Change the airfoil airfoil the angle angle of 5° and then then again note note the correspon corresponding ding values values in the the pressure pressure distribution tubes. 6. Follow Follow the same same procedure procedure for differe different nt angles angles in the the symmetric symmetric airfoil airfoil.. 7. Tabulate Tabulate the the readings readings and and calculate calculate pressure pressure for for each angles angles.. 8. Plot the graph graph by using using the pressu pressure re distribut distribution ion on symmetr symmetric ic airfoil airfoil to the pressure pressure in mm of water.
Value of pressure co-efficient on symmetrical airfoil
S. no
Locati Locations ons
Angle Angle of attack attack in degree degree [Initi [Initial al Manome Manometer ter Readin Reading g =6cm] =6cm] 0
5
10
15
-5
-10
-15
RESULT Thus the pressure distribution over symmetric airfoil is calculated. Ex.no x.no:0 :05 5
PRES PRESSU SUR RE DIS DISTR TRU UBTIO BTION N OV OVER UN UNSYMM SYMME ETRIC TRIC AIR AIRFO FOIL IL
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 static pres pressur suree in cm [fro [from m Manom Manomete eterr 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 subson subsonic ic wind tunnel tunnel for for about 10 minute minutess in order to obtain obtain the indica indicator tor which which is required for our experiments. 3. By turning turning the AC AC motor motor adjust the the speed speed of the air air in the air air speed of of the air in the the air speed speed indicator which is required for our experiments. 4. Place the the un-symmetr un-symmetric ic airfoil airfoil in zero angle angle of attack attack and then note note the correspo corresponding nding values values in locations 1 to 13 in pressure distribution tubes. 5. Change Change the airfoil airfoil angle angle to 5° and then again again note note the correspon corresponding ding values values in the the pressure pressure distribution tubes. 6. Follow Follow the same same procedure procedure for differe different nt angle angle in the the un-symmetri un-symmetricc airfoil. airfoil. 7. Tabulate Tabulate the the reading reading and and calculat calculatee pressure pressure for for each each angle. angle. 8. Plot the graph graph by using using the pressu pressure re distribut distribution ion for each each angle on un-sy un-symmetri mmetricc airfoil 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 dimensio dimensional nal models models are kept kept in text section section is made made visible visible by placing placing silver silver threads threads the water channels is well studied for the study the effect of models on the flow pattern. 2. When kept kept in a stream line line flow flow the followin following g models are are used for flow flow visualiza visualization tion.. (1) Water flow flow channel channel and (2) two dimension dimensional al surfaces. surfaces. 3. Laminar Laminar flow flow of water water in in a channel channel is in flow condition condition.. 4. For above above condition condition operat operatee the variabl variablee drive in in clockwise clockwise direct direction. ion. 5. Observe Observe the the condit condition ion of flow flow shoul should d be dominant. 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 equipmen equipmentt is made of strain strain less factor factor tory tory in which which contact contact portions portions are made made for flow path. path. 9. The The flow flow path path len lengt gth h –‘6 –‘6’. ’.
10. Width of channel is two sideways ‘6’. 11. Width o channel in center ‘a’. 12. Curved blade at entry entry and the other other end is made made for smooth flow. flow. 13. The curve blades can be removable type type on the other end end for different condition. condition. 14. A common shaft is connected by belt belt to DC digital digital motor. 15. The RPM of motor motor can be read in digit digital al meter. meter. 16. Once the experiment is is completed drain the water. 17. The water height in channels channels should not be more 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 b y given objects. APPARATUS REQUIRED Airfoil (or) the plate buff bodies THEORY 1. The most most common common method of flow flow field visuali visualizatio zation n is sum significat significatee advantages advantages of 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 Filament can be used used to final key locat location ion such such as stagnation stagnation point points, s, so can easily easily shoe the the extent 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, model, essentially its concept of of electrical cartridge heat over the diesel bottle. Sump bottles, air supply supply from blower of demote and smoke smoke distribution. PROCEDURE 1. Cover the back back side side of test section section with with dark dark cloth. cloth. 2. Swit Switch ch ON the the lig light ht.. 3. Keep Keep the the needle needle value value closed closed.. 4. Fill the the overhead overhead bottle bottle with with diesel diesel and check check level. level. 5. Connect Connect the electr electrical ical supply supply of of cartridge cartridge heated heated to contro controll panel. panel.
6. Fix the the require require model model is test test sectio section n (or) (or) orientat orientation. ion. 7. Connect Connect the the air inlet inlet and smoke smoke generatio generation n to the outle outlet. t. 8. Initially Initially open the the needle needle value value and allow the diesel diesel.. 9. Now switch switch ON ON the neater neater contro controll unit unit and keep keep out out it minimu minimum. m. 10. After the initial heating heating is done the smoke starts coming coming out of smoke distribution 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 DC motor controlled controlled and it to XY the fan. 12. Adjust the sapped to get get uniform visible smoke smoke and airfoil model higher velocity velocity will diffuse the smoke. 13. The used diesel controller controller in the sump bottle and outlet outlet smoke pipes may be put back back over heat bottle. 14. The observe the flow pattern at different different orientation of models. 15. After the experiment is over of the the heat controller close the needle needle value and switch off the light. light. 16. Allow the flow blower and fan to operate the far far sometime to drive drive unused smoke. smoke. CAUTIONS 1. During During experiment experimental al check for for blockage blockage due to condens condensed ed oils in smoke smoke outlet outlet leading leading to distribution and drain onto sump bottle. 2. Check period periodically ically that that adequate adequate amount amount of diesel diesel oil is is available available in the the over neat bottle. bottle. 3. Never switch switch ON ON the heater heater for long long time time the diesel diesel oil being being supply supply to to unit. 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 Filament can be used used to find key locatio locations ns such as stagnat stagnation ion points points so can bubble bubble smoke 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 supply from blower of demote and smoke smoke distribution. PROCEDURE 1. Cover the back back side side of test section section with with dark dark cloth. cloth. 2. Swit Switch ch ON the the lig light ht.. 3. Keep Keep the the needle needle value value closed closed.. 4. Fill the the overhead overhead bottle bottle with with diesel diesel and check check level. level. 5. Connect Connect the electr electrical ical supply supply of of cartridge cartridge heated heated to contro controll panel. panel. 6. Fix the the require require model model is test test sectio section n (or) (or) orientat orientation. ion. 7. Connect Connect the the air inlet inlet and smoke smoke generatio generation n to the outle outlet. t. 8. Initially Initially open the the needle needle value value and allow the diesel diesel.. 9. Now switch switch ON ON the neater neater contro controll unit unit and keep keep out out it minimu minimum. m. 10. After the initial heating heating is done the smoke starts coming coming out of smoke distribution 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 DC motor controlled controlled and it to XY the fan. 12. Adjust the sapped to get get uniform visible smoke smoke and airfoil model higher velocity velocity will diffuse the smoke. 13. The used diesel controller controller in the sump bottle and outlet outlet smoke pipes may be put back back over heat bottle. 14. The observe the flow pattern at different different orientation of models. 15. After the experiment is over of the the heat controller close the needle needle value and switch off the light. light. 16. Allow the flow blower and fan to operate the far far sometime to drive drive unused smoke. smoke. CAUTIONS 1. During During experiment experimental al check for for blockage blockage due to condens condensed ed oils in smoke smoke outlet outlet leading leading to distribution and drain onto sump bottle. 2. Check period periodically ically that that adequate adequate amount amount of diesel diesel oil is is available available in the the over neat bottle. bottle. 3. Never switch switch ON ON the heater heater for long long time time the diesel diesel oil being being supply supply to to unit. 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 x.no:0 :09 9
USE USE OF SCH SCHLIE LIEREN REN SY SYSTEM STEM TO VISUA ISUAL LIZE IZE SHO SHOCK
AIM To study about use of Schlieren s ystem to visualize shock. APPARATUS REQUIRED
Recording device Mirror Test section Light source Model PROCEDURE 1. During During a test, the model model is placed placed on test test section section of tunnel tunnel of air is made to flow flow part the the model. model. 2. In some wind wind tunnel tunnel tests tests flow visuali visualizatio zation n techniques techniques are are used to produce producess and provide provide diagnostic information about the models.
3. The older flow visualization techniques are Schlieren photography. 4. Schlieren Schlieren systems systems to to visualiza visualization tion the the flow flow away from surface surfaces. s. 5. It uses the the two objects objects concave concave mirrors mirrors on either either sides sides of test sectio section n of wind tunnel 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 parallel rays rays of light encounte encounterr density density gradient gradient in test test section section light is bent. 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::C UNIVERSITY::CHENNAI-25 HENNAI-25
REGULATION 2008
DATE: 02-01-2013
S.NO
APPROVED BY
LIST OF EXPRIMENTS
PAGE NO
01
STUDY OF SUBSONIC WIND TUNNEL
02
FORCE ME MEASUREMENTS US USING ING SY SYMMETRIC TRIC AIRF IRFOIL
03
PRESSURE DI DISTRIBUTION OF OF CI CIRCULAR CY CYLINDER
04
PRE PRESSU SSURE DISTR ISTRIB IBU UTIO TIONS OV OVER A SYMM SYMME ETRIC TRIC AIRFO IRFOIL IL
05
PRE PRESSU SSURE DISTR ISTRU UBTIO BTION N OVER UN UNSYMM SYMME ETRIC TRIC AIRFO IRFOIL IL
06
FLOW VISUALIZATION USING WATER TER CHANNEL
07
SMOKE FLOW VISUALAIZATION
08
GENERATION OF LIFT AND TIP VORTICS
09
USE OF OF SC SCHLIER IEREN SY SYSTEM TO TO VISUALIZE SH SHOCK
STAFF INCHARGE
