5.3 Natural Ventilation
175
(a) Calculate the centre of gravity of the surface h-T by the shoelace formula.
(b) Determine the NVP by the Voropaev method.
Temp.
T
Depth
h
Point
(ºC)
(m)
A
6
50
B
10
175
C
16
175
D
15
0
E
5
0
B
A
D
C
E
Solution
(a) First, the h-T diagram is constructed with the data from the statement. Thus, the
diagram is broken down into geometric figures of a known centre of gravity:
0
25
50
75
100
125
150
175
200
0
2
4
6
8
1 0
1 2
1 4
1 6
1 8
1
2
3
4
5
h
(m)
T ( o C)
According to the above, the areas would be
7 :
7 Note that since temperature differences are to be measured, it makes no difference whether the
graph is in °C or in K.
175
(a) Calculate the centre of gravity of the surface h-T by the shoelace formula.
(b) Determine the NVP by the Voropaev method.
Temp.
T
Depth
h
Point
(ºC)
(m)
A
6
50
B
10
175
C
16
175
D
15
0
E
5
0
B
A
D
C
E
Solution
(a) First, the h-T diagram is constructed with the data from the statement. Thus, the
diagram is broken down into geometric figures of a known centre of gravity:
0
25
50
75
100
125
150
175
200
0
2
4
6
8
1 0
1 2
1 4
1 6
1 8
1
2
3
4
5
h
(m)
T ( o C)
According to the above, the areas would be
7 :
7 Note that since temperature differences are to be measured, it makes no difference whether the
graph is in °C or in K.