International Research Journal of Applied and Basic Sciences
© 2015 Available online at www.irjabs.com
ISSN 2251-838X / Vol, 8 (1): 30-40
Science Explorer Publications
Domed Roofs for Better Energy Efficient
Architecture; Experimental Validation of Wind
Pressures on a Hemispherical Dome
Mohammadjavad Mahdavinejad, Seyedehmasoumeh Shafiee, Vahidreza Abossedgh
Faculty of Art and Architecture, Tarbiat Modares University, Tehran, Iran
Corresponding Author email: [email protected]
ABSTRACT: This paper is to measure wind velocity on dome in case of old houses of Isfahan and
Kashan in Iran. To analyze wind velocity, the pressure coefficient for zero and ninety degrees angles
were calculated separately for those domes in order to compare the results with one or more valid
reference; after studying the effects of wind on domes the references were selected for comparing, and
the experimental results achieved by Mr. Taylor and the experimental results by Mr. Bahadori were
compared to the results achieved by the devices installed on the domes of Isfahan and Kashan and these
comparison lead to noticeable results related to computer calculations in the wind tunnel model. The
results shows whether these calculations could be used in Iran or not, and could these calculations be
used instead of the actual measuring. In this paper, all the measurements have been done in real
environment system.
Key words: dome-shaped roofs; natural ventilation; wind pressure coefficient, energy efficiency.
INTRODUCTION
This paper is to analyze domed roofs for better energy efficient architecture through experimental
validation of wind pressures on a hemispherical dome. Therefore the paper concentrated on Taylor (1991)
research to show how accurate it was and how it may help future investigations.
Research Background
Literature review of the research shows that architectural design process has a determining role in final
form of the project and materialize energy efficiency characteristics of an architectural project (Mahdavinejad et al.,
2012a,b,c,d,e). It is important to mention some pioneer researches such as comparative analysis of wind flow in
Yazi and Kermani wind towers (Mahdavinejad and Javanrodi K. 2012), efficient roof shapes through wind flow and
indoor temperature, case studies: flat roofs and domed roofs (Mahdavinejad and Javanrodi K. 2014), lighting
characteristics and building mass (Mahdavinejad and Matoor, 2012) and other architectural design elements
(Mahdavinejad et al., 2013a,b,c,d) especially building materials and configuration (Nazari et al.,2014).
Hemispherical domes are often used in Iran in order to cover buildings such as mosques, shrines,
churches, schools etc. But their desirable thermal function has made these domes useful in other buildings such as
markets and bazaars in Iran. (Bahadori and Faghih, 2010) Traditionally hemispherical domes were used in Iran in
order to cover the buildings with large areas. These domes have played major roles in Iranian architecture and
have had strong effect on cooling duties of the Buildings. (Bahadori and Faghih, 2010) According to
Ghasempourabadi et al. (2011) domed roof has a lot to do with air flow characteristics especially in two-shelled
domes in Iranian traditional architecture.
It is very important to explain that natural energy efficient technologies concentrate of air flow more than
other ones (Golamirostam et al., 2014). In Iran, lots of samples are seen where the vastness of the dome is shown
compared to other archer of the building such as Isfahan Mosque which has 450 arches and only 2 domes, and in
a historical period it is seen that 16 openings were taken and the Nezam ol Molk dome was built instead and the
height of the dome building itself has its visual effects and gives the feeling of vastness to the audience and this
building can be seen from 18 kilometers distance from the building. Therefore the dome of the house is an
Intl. Res. J. Appl. Basic. Sci. Vol., 9 (1), 30-40, 2015
important part of the house. Sometimes a building is entirely a dome which is more commonly seen in shrines and
tombs.
On the other hand initial researches shows that the solar energy which is received by hemispherical domes
is almost the same amount as the solar energy of flat roof with the same area. This received energy causes the
roof to be hotter than the room temperature. Because of the wind and natural ventilation, energy efficiency finds a
desirable trend. The geometric design of these dome-shaped roofs cause the wind velocity to increase on their
surface, which will result in increasing the heat transfer coefficient. Also, since the area of this dome is larger than
the flat area, the heat transfer of the dome-shaped roofs are more important. These information could be used to
evaluate the heat transfer functions of dome-shaped roofs. (Bahadori and Faghih, 2010) Because of the reasons
mentioned above, lots of building across the world have dome-shaped roofs. According to the mentioned points we
are trying to compare the wind pressure coefficient on domes in Iran in Kashan and Isfahan with other values of
pressure coefficient which were calculated by Taylor (1991), and Bahadori and Faghih (2010). This comparison
could be a step to find some useful guidelines for dome-shaped roofs in Iran.
METHODOLOGY
The aim of the present research is to compare the quantitative results of the tests which were done on the
domes of Isfahan and Kashan in order to validate the studies done by Taylor (1991) and Bahadori (2010), and to
do so four tests were done in Isfahan and Kashan cities (two test in each city) and the results of the tests were
compared and analyzed separately once with Taylor test results and once with Bahadori test results in order to
determine their level of validity and usage in Iran.
Taylor`s theory
The study of aerodynamic pressure on hemispherical dome is done by few researchers and those
researches have focused their attention on mean, mean time and the pressure itself. Among these, none has paid
attention to the peak pressure, or the effects of turbulence on the density of the natural wind. So Taylor has done
some research in order to present some information about local pressure on the peak of the dome and average
local pressure in a turbulent wind current, so that these information could be used in wind engineering. He specially
has studied the effects of Reynolds number (to the ultra-critical type with the Reynolds number of 0.3×105) on the
density and turbulence (10% and 20%) on the boundary layer with the natural wind. He has done extensive studies
on the aerodynamic pressure distribution on hemispherical domes in the boundary layer currents which includes
the determination of average, standard deviation, minimum, maximum, and also the average of surface pressure
coefficient. He calculated the pressure (which is also known as the static pressure in free current) with the increase
of 7½ for domes with the height and diameter ratio of 1, ½ and ⅓ and the Reynolds number between 1.1×105 and
3.1×105, in two different turbulence pressure. For that modeling he used the wind tunnel with the boundary layer
wind of 30 kW in Monash University with the working range of 1.23×0.92m and a hemispherical dome with the
diameter of 300mm and K/D hardness of 10-7 for his experimental studies.
He then according to the achieved results and also based on higher Reynolds number calculations on cylinders,
studied the effects of Reynolds number and the level of turbulence on the average, standard deviation, peak and
average pressure of the surface, and then he determined the critical parts and their pressures for future designs
(Taylor, 1991).
DISCUSSION
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Intl. Res. J. Appl. Basic. Sci. Vol., 9 (1), 30-40, 2015
Figure 1. Experimental results for Cp while β=0 (experimental results for wind pressure coefficient at 0° angle) in Isfahan in
comparison with Taylor test results
Figure 2. Experimental results for Cp while β=0 (experimental results for wind pressure coefficient at 0° angle) in Kashan in
comparison with Taylor test results
Figures 1 and 2 shows the experimental values of Cp achieved from different parts of domes in Isfahan and
Kashan on 0° angle in comparison with experimental results achieved by Taylor. The criteria ϕ (angle) shows the
positions of pressure labels, which is zero degrees for positions facing the wind and 180 degrees for positions
opposing the wind. ϕ=90 at the peak of the dome. As it can be seen in the figures, the maximum amount for Cp are
for points facing the wind (ϕ=0). According to the tests done, this value was about 0.9 in Kashan and around 0.7 in
Isfahan, in a way that in the present analysis in comparison to Taylor results this value is a little less in Isfahan and
a little more in Kashan. The minimum amount for Cp is at the peak of the dome where the angle is 90 degrees; and
the results achieved from this point are less than Taylor`s results. This point has less pressure coefficient in
Kashan that in Isfahan. The amount was -1.4 in Isfahan and -1.5 in Kashan which have a 0.1 and 0.2 variance with
Taylor results. Obviously, since the maximum amount of velocity is achieved at the peak of the dome, therefore the
minimum pressure is also achieved there.
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Intl. Res. J. Appl. Basic. Sci. Vol., 9 (1), 30-40, 2015
The two sets of results are not completely accurate; therefore some difference between these results could be
expected. However because of the separation of the wind and the surface which happens at the back of the dome
(ϕ>90), more difference sould be expected in the set of data there. For Re=3.2×105 Taylor has reported the 0.75
value for Cp where ϕ=0 and -1.35 value for Cp where ϕ=90. Because of the high Reynolds number the separation
happens behind the roof. Therefore the difference between the two sets of results in this are seems acceptable.
As it can be seen in the above pictures, the amount of Cp (Pressure Coefficient) which was achieved from
experimental simulation is more than the data presented by Taylor before the peak in the dome, and after the 90
degrees angle this amount is less that Taylor`s results. The minimum difference between the two sets of data
occurs between the 50 degrees and 70 degrees angles.
Figure 3. Experimental results for Cp while β=90 (experimental results for wind pressure coefficient at 90° angle) in Isfahan in
comparison with Taylor test results\
Figure 4. Experimental results for Cp while β=90 (experimental results for wind pressure coefficient at 90° angle) in Kashan in
comparison with Taylor test results
Figures 3 and 4 shows the experimental results on different points of the domes in Isfahan and Kashan at
the angle of 90 degrees in comparison with the experimental results from Taylor. The ϕ Criterion (angle) in this
figure show the positions of pressure labels, which are from 0 to 180 degrees. However since the two sides of the
diagram are identical and have same values, the degrees on the diagrams were only shown up to 90 degrees. Also
because of the symmetry of the dome, only half of it was tested. Therefore the boundary criteria for all surfaces is
asymmetry.
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Intl. Res. J. Appl. Basic. Sci. Vol., 9 (1), 30-40, 2015
Like previous diagrams, at the peak of the dome ϕ is equal to 90 degrees. As it is shown in the figures, the
maximum amount for Cp is achieved at (ϕ=0). According to the tests done in this research the amount of Cp for this
point was -1.2 for Kashan and -0.8 for Isfahan, and this amount was -1.2 in Taylors experimental studies. The
results for Isfahan is about 0.4 more than Taylor`s. The minimum amount for Cp is at the peak of the dome where
the angel is 90 degrees. The results achieved in this angle were both in Isfahan and Kashan Lower that the results
from Taylors studies.
The results achieved from Kashan were generally closer to Taylor`s results that the results achieved from
Isfahan and the minimum difference between the two sets occurred around the 90 degrees angle in both diagrams.
In figures 3 and 4 it can be seen that the results achieved from Isfahan increases in comparison toTaylor`s results
after the angle of 75 degrees and these results from Kashan increases in comparison to Taylor`s results after the
angle of 45 degrees, but before these angles the results are lower that Taylor`s results.
Figure 5. Experimental results for Cp while β=0 (experimental results for wind pressure coefficient at 0° angle) in Isfahan in
comparison with Bahadori test results
Figure 6. Experimental results for Cp while β=0 (experimental results for wind pressure coefficient at 0° angle) in Kashan in
comparison with Bahadori test results
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Intl. Res. J. Appl. Basic. Sci. Vol., 9 (1), 30-40, 2015
Figures 5 and 6 shows the experimental results for Cp which were achieved in different points of the domes
in Isfahan and Kashan at the angle of zero degrees in comparison with the numeral results achieved by Bahadori.
As it was mentioned before, the maximum amount for Cp is for points which are facing the wind (φ=0). In numerical
studies done by Bahadori this value is between 0.2 and 0.4 and it is lower that the experimental results both in
Isfahan and Kashan. The minimum amount of Cp according to experimental results is at the peak of the dome (at
the angle of 90 degrees) and since Kashan has a lower pressure coefficient than Isfahan, this amount was equal to
the numerical results achieved by Bahadori in Isfahan and this amount was about 0.15 lower than the numerical
results achieved by Bahadori.
The difference between the two sets of experimental results from this research weather on Isfahan or in
Kashan were higher in comparison with Bahadori`s results than in comparison with Taylor`s results.
As it can be seen in the above figures, the values for Cp (Pressure Coefficient) achieved from experimental
simulation in both diagrams are higher that Bahadori`s numerical data before the angle of 45 degrees and they are
lower after 45 degrees.
Figure 7. Experimental results for Cp while β=90 (experimental results for wind pressure coefficient at 0° angle) in Isfahan in
comparison with Bahadori test results
Figure 8. Experimental results for Cp while β=90 (experimental results for wind pressure coefficient at 0° angle) in Kashan in
comparison with Bahadori test results
Figures 7 and 8 shows the experimental results of Cp achieved from different points of the domes in
Isfahan and Kashan at the angle of zero degrees in comparison with the numerical results presented by Bahadori.
As it was mentioned before, since both sides of the diagram is completely symmetric and have same values, the
degrees is the diagram were considered only up to 90 degrees.
The maximum value for Cp is for the point of φ=0 and the experimental values achieved for Isfahan is -0.8 and for
Kashan is -1.2, but this value in Bhadori`s numerical results is about -1. Therefore the achieved experimental
results in Isfahan`s diagram is about 0.2 more and in Kashan`s Diagram is about 0.2 less than the numerical
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Intl. Res. J. Appl. Basic. Sci. Vol., 9 (1), 30-40, 2015
results for the point φ=0. The experimental results for Cp for the angle of 90 degrees were less than Bahadori`s
numerical results both in Isfahan and Kashan.
In Bahadori`s numerical results the minimum value for the pressure coefficient is at the angle near 90 degrees and
after that the numerical values keep increasing. However in experimental values the minimum value is for exactly
the angle of 90 degrees. Also the difference between the two sets of numerical and experimental results were more
Kashan than the difference in Isfahan. These differences between the angle of 25 and 50 for Isfahan`s diagram
and between the angle of 80 and 90 degrees for Kashan`s diagram is at its minimum value.
You can see the error percentage between the experimental results of the pressure coefficient in β=0 and
β=90 in Kashan and Isfahan and the experimental and numerical results from Taylor and Bahadori in the
following table:
Table 1.The error percentage for dome-shaped roofs in Isfahan city in β=0
Column
1
2
3
4
5
6
7
8
9
10
11
12
Isfahan 0
0.7324
0.6901
0.5223
0.3662
0.1339
-0.3664
-0.7091
-0.8583
-1.2013
-1.356
-1.4284
-1.3512
Taylor 0
0.74
0.7
0.5
0.37
0.11
-0.4
-0.77
-0.9
-1.1
-1.2013
-1.356
-1.3512
avrage
Ttest
Error 1
-1.027027
-1.414286
4.46
-1.027027
21.727273
-8.4
-7.909091
-4.633333
9.2090909
12.877716
5.339233
0
8.8355781
0.9679419
Bahadori 0
0.6
0.48
0.25
0.29
0.37
-0.25
-0.4
-0.65
-0.8
-0.92
-1.3
-0.82
avrage
Ttest
Error 2
22.066667
43.770833
108.92
26.275862
-63.81081
46.56
77.275
32.046154
50.1625
47.391304
9.8769231
64.780488
41.787295
0.6551717
The comparison between the experimental values achieved for the pressure coefficient of the wind in
Isfahan`s domes with the angle of zero degrees and the values achieved by Taylor and Bahadori can be seen as
the error percentage in the above table. In this comparison; the comparison reference for Error 1 is the numbers
from the Taylor diagram and for Error 2 is the numbers from the Bahadori diagram. After number by number
comparison, an average of the errors was calculated. The average error in comparison with Taylor`s results was
8.835781 and the average error in comparison with Bahadori`s results was 41.787295. After that on all the
numbers achieved from Isfahan two Ttests were separately done, one with all Taylors numbers and one with
Bahadori`s number, and in comparison with Taylor`s numbers Ttest=0.9679419 and in comparison with Bahadori`s
numbers Ttest=0.6551717 were achieved. Df=1; which means the more this number is close to 1 the difference is
less and the results more desirable and the more this number is close to zero the difference is more. As it can be
seen in the table the Ttest values in comparison with Taylor`s results is closer to 1 than Bahadori`s results and this
shows that this research`s results were closer to Taylor`s results.
Table 2.The error percentage for dome-shaped roofs in Kashan city in β=0
Column
1
2
3
4
5
6
7
8
9
10
11
12
Kashan 0
Taylor 0
Error 1
Bahadori 0
Error 2
0.8602
0.7552
0.6005
0.4312
0.1992
-0.3928
-0.7651
-0.9234
-1.3345
-1.4201
-1.5074
-1.4568
0.74
0.7
0.5
0.37
0.11
-0.4
-0.77
-0.9
-1.1
-1.2013
-1.356
-1.3512
average
Ttest
16.243243
7.8857143
20.1
16.540541
81.090909
-1.8
-0.636364
2.6
21.318182
18.213602
11.165192
7.8152753
21.764178
0.946178
0.6
0.48
0.25
0.29
0.37
-0.25
-0.4
-0.65
-0.8
-0.92
-1.3
-0.82
average
Ttest
43.366667
57.333333
140.2
48.689655
-46.16216
57.12
91.275
42.061538
66.8125
54.358696
15.953846
77.658537
44.033512
0.0130647
The comparison between the experimental values achieved for the pressure coefficient of the wind in
Kashan`s domes with the angle of zero degrees and the values achieved by Taylor and Bahadori can be seen as
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Intl. Res. J. Appl. Basic. Sci. Vol., 9 (1), 30-40, 2015
the error percentage in the above table. In this comparison; the comparison reference for Error 1 is the numbers
from the Taylor diagram and for Error 2 is the numbers from the Bahadori diagram. After number by number
comparison, an average of the errors was calculated. The average error in comparison with Taylor`s results was
21.764178 and the average error in comparison with Bahadori`s results was 44.033512. After that on all the
numbers achieved from Isfahan two Ttests were separately done, one with all Taylors numbers and one with
Bahadori`s number, and in comparison with Taylor`s numbers Ttest=0.946178 and in comparison with Bahadori`s
numbers Ttest=0.0130647 were achieved. Df=1; As it can be seen in the table the Ttest values in comparison with
Taylor`s results is closer to 1 than Bahadori`s results and this shows that this research`s results were closer to
Taylor`s results.
Table 3.The error percentage for dome-shaped roofs in Isfahan city in β=90
Column
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Isfahan 90
-0.8076
-0.8628
-0.8914
-0.9022
-0.9255
-0.9332
-0.93955
-0.9406
-0.9722
-1
-1.087
-1.12
-1.1903
-1.2273
-1.2852
-1.308
-1.3431
-1.3984
-1.4122
-1.4203
Taylor 90
-1.15
-1.138
-1.134
-1.13
-1.125
-1.12
-1.123
-1.25
-1.23
-1.22
-1.24
-1.25
-1.26
-1.27
-1.275
-1.28
-1.284
-1.29
-1.298
-1.3
average
Ttest
Error 1
-29.77391
-24.18278
-21.3933
-20.15929
-17.73333
-16.67857
-16.33571
-24.752
-20.95935
-18.03279
-12.33871
-10.4
-5.531746
-3.362205
0.8
2.1875
4.6028037
8.4031008
8.798151
9.2538462
12.523513
0.0183418
Bahadori 90
-0.98
-0.97
-0.973
-0.981
-0.9
-0.91
-0.92
-0.93
-0.97
-1.05
-1.08
-1.1
-1.2
-1.21
-1.22
-1.23
-1.235
-1.37
-1.5
-1.42
average
Ttest
Error 2
-17.59184
-11.05155
-8.386434
-8.03262
2.8333333
2.5494505
2.125
1.1397849
0.2268041
-4.761905
0.6481481
1.8181818
-0.808333
1.4297521
5.3442623
6.3414634
8.7530364
2.0729927
-5.853333
0.0211268
6.3968431
0.8829803
Table 4.The error percentage for dome-shaped roofs in Kashan city in β=90
Column
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Kashan 90
-1.2049
-1.2008
-1.1987
-1.903
-1.1858
-1.1664
-1.1853
-1.234
-1.3207
-1.3388
-1.3492
-1.3574
-1.3608
-1.3722
-1.3819
-1.3988
-1.4055
-1.4117
-1.4206
-1.4388
Taylor 90
-1.15
-1.138
-1.134
-1.13
-1.125
-1.12
-1.123
-1.25
-1.23
-1.22
-1.24
-1.25
-1.26
-1.27
-1.275
-1.28
-1.284
-1.29
-1.298
-1.3
average
Ttest
Error 1
4.773913
5.5184534
5.7054674
68.40708
5.4044444
4.1428571
5.5476402
-1.28
7.3739837
9.7377049
8.8064516
8.592
8
8.0472441
8.3843137
9.28125
9.4626168
9.4341085
9.4453005
10.676923
13.956528
0.0032567
Bahadori 90
-0.98
-0.97
-0.973
-0.981
-0.9
-0.91
-0.92
-0.93
-0.97
-1.05
-1.08
-1.1
-1.2
-1.21
-1.22
-1.23
-1.235
-1.37
-1.5
-1.42
average
Ttest
Error 2
22.94898
23.793814
23.1963
93.985729
31.755556
28.175824
28.836957
32.688172
36.154639
27.504762
24.925926
23.4
13.4
13.404959
13.270492
13.723577
13.805668
3.0437956
-5.293333
1.3239437
19.980916
0.0001102
The comparison between the experimental values achieved for the pressure coefficient of the wind in
Isfahan`s domes with the angle of 90 degrees and the values achieved by Taylor and Bahadori can be seen as the
error percentage in the above table. In this comparison; the comparison reference for Error 1 is the numbers from
the Taylor diagram and for Error 2 is the numbers from the Bahadori diagram. After number by number
comparison, an average of the errors was calculated. The average error in comparison with Taylor`s results was
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Intl. Res. J. Appl. Basic. Sci. Vol., 9 (1), 30-40, 2015
12.523513 and the average error in comparison with Bahadori`s results was 6.3968431. After that on all the
numbers achieved from Isfahan two Ttests were separately done, one with all Taylors numbers and one with
Bahadori`s number, and in comparison with Taylor`s numbers Ttest=0.946178 and in comparison with Bahadori`s
numbers Ttest=0.08829803were achieved. Df=1; As it can be seen in the table the Ttest values in comparison with
Bahadori`s results is closer to 1 than Taylor`s results and this shows that this research`s results were closer to
Bahadori`s results.
The comparison between the experimental values achieved for the pressure coefficient of the wind in
Kashan`s domes with the angle of 90 degrees and the values achieved by Taylor and Bahadori can be seen as the
error percentage in the above table. In this comparison; the comparison reference for Error 1 is the numbers from
the Taylor diagram and for Error 2 is the numbers from the Bahadori diagram. After number by number
comparison, an average of the errors was calculated. The average error in comparison with Taylor`s results was
13.956528 and the average error in comparison with Bahadori`s results was 19.980916. After that on all the
numbers achieved from Isfahan two Ttests were separately done, one with all Taylors numbers and one with
Bahadori`s number, and in comparison with Taylor`s numbers Ttest=0.0032567 and in comparison with Bahadori`s
numbers Ttest=0.0001102 were achieved. Df=1; As it can be seen in the table the Ttest values in comparison with
Bahadori`s results is closer to 0 than Taylor`s results and this shows that this research`s results were have
significant variance with Taylor`s and Bahadori`s results.
As it was mentioned before the two sets of experimental results are not quite accurate; therefore the
difference between these two set of results could be expected. However because of the separation of the wind and
the surface that happens at the back of the dome (φ>90) the difference between the two sets of data could be
expected in this area. Taylor reported the value of Cp as 0.75 for φ=0 and Re=3.2×105 and he also reported the
value of Cp as -1.35 for φ=90 and Re=3.2×105. Because of the high Reynolds number the separation happens at
the back of the dome. Therefore the difference between the two sets of results is acceptable in this area.
Ttests are commonly used in order to determine the level of meaningfulness of the difference between two
averages. This is an experimental hypothesis, but in formal meaningfulness tests, the experimental hypothesis is
not directly tested, but it`s negative form (which is known as H0 or Null hypothesis) is tested.
The device for measuring wind pressure coefficient in Kashan and Isfahan
In order to determine the wind pressure coefficient in Kashan and Isfahan domes, the amount of the
passing wind is calculated in cubic meter per minute or cubic foot per minute (also known as cmm and cfm) using
the Tes-1341 Hot-Wire Anemomete device.
Figure9.
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Intl. Res. J. Appl. Basic. Sci. Vol., 9 (1), 30-40, 2015
Some of the specifications of this device is as follows
TES 1341 Hot-Wire Anemometer
FEATURE:
Fast response probe.
-Air flow volume.
-Instant / Avg / ⅔V max flow measurement
-Velocity m/s, f t/ min, knots km / hr , mph, bft.
-Temperature & Humidity measurement.
-Calculate Dew point temperature, wet bulb temperature, wind chill
temperature, Humidex temperature and Heat index temperature.
-Data hold & Maximum/Minimum/ Average function.
-Manual data memory and read function (5× 99 sets)
-Auto data memory and read function (5× 99 sets)
-LCD triple display.
-Telescoping probe.
-USB Interface.
Specifications
Table5.
Function
Air Velocity
Air Flow
Volume
Relative
Humidity
Temperature
West Bulb
Temperature
Dew Point
Temperature
Measuring
Range
0.1 to 30.0
m/s
0 to 999900
3
m /min
10 to 95%
RH
Resolution
-10 to 60 ˚C
5 to 60 ˚C
0.1˚C
0.1˚C
-15 to 49 ˚C
0.1˚C
Accuracy
0.01 m/s
3
0.001 m /min
0.1%RH
±3% of
reading ±
1%FS
±3%RH (at
25˚C, 30 to
95%RH)
±5%RH (at
25˚C, 10 to
30%RH)
±0.5˚C
Calculated
Table6.
Response time
Manual Memory Capacity
Auto Memory Capacity
Operating Conditions
Power Source
Battery Life
Size
Weight
Accessories
1 second
5×99 sets. (Direct reading from
LCD display)
5×99 sets. (Direct reading from
LCD display)
0 ˚C ̴ 50˚C (32˚F ̴ 122 ˚F), ≤
80% R.H.
6 pcs size AAA Battery
Approx. 400g (including Probe)
135(L) × 72(W) ×31(H)mm
Approx. 400g (including Proble)
Instruction manual, Battery,
USB Cable, CD Software,
Carrying case
39
Intl. Res. J. Appl. Basic. Sci. Vol., 9 (1), 30-40, 2015
CONCLUSION
The adaptive comparison between the measured values and the simulation ran by Bahadori shows that the
model presented by Bahadori has acceptable validity. Because as it was seen above the average error percentage
for pressure coefficient on Isfahan`s domes at the angles of zero and 90 degrees in comparison with Bahadori`s
results were 41.787295 and 6.3968431 and also in Kashan domes these values are for the same angles
44.033512 and 19.980916.
The measured values shows that the calculation pattern presented by Taylor (Numerical) has acceptable
validity for dome surfaces. Because as it was seen above the average error percentage for pressure coefficient on
Isfahan`s domes at the angles of zero and 90 degrees in comparison with Taylor`s results were 8.835781 and
12.523513 and also in Kashan domes these values are for the same angles 21.764178 and 13956528. The
analyses shows that the test results of this research is closer to Taylor`s results that Bahadori`s numerical results
(except for Isfahan`s sample at the angle of zero degrees).
Dome shaped roofs have special and specific usages in Islamic countries and especially in Iran. These
roofs have had special place in Iranian architecture before and after Islam. There are different kinds and forms of
dome-shaped roofs based on their usages in different climates and they will result in special air currents which will
result in increasing the desirability, welfare and also decreasing the energy usage for cooling purposes.
ACKNOWLEDGEMENTS
This paper is result of M. Sc. Dissertation of Seyedehmasoumeh Shafiee and Vahidreza Abossedgh which
has been done under supervision of Dr. Mohammadjavad Mahdavinejad in TMU (Tarbiat Modares University).
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40