IIIF Color HighRes
National Institute of Informatics - Digital Silk Road Project
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| IIIF Color HighRes |
| Scientific Results of a Journey in Central Asia, 1899-1902 : vol.1 |
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| Vertical section of River. | |
| 10 April 1900. Kum-tschapghan. |
Citation Information
METHODS OF CALCULATING THE HYDROMETRIC DATA. 31
increases. Then, denoting the vertical lines N.0,, N2 02.....N by pI,
p„ .... pn_I, we readily obtain
Q = v=pz h 2 h2 + v2p2 h2 h3 + .... + vn _ IL n_ I hn +hn (6)
2 2
and A = p hI 2 h2 + p2 h2 2 h3 + .... + pn _ I hn 2+hn (7)
From (6) and (7), by means of equations (2) and (4), we are able to obtain the values of dm and Vnt. If the n divisions are all equal, i. e.
h2=h2=....=hn=h and b=nh, the formul (6), (7), (2), and (4) become simplified thus
Q = h(v,pl + v2p2 + .... + vn_Ipn—_) hZvp (8)
A = h(pI +p2 + .... +pn_,) = h2p (9)
V. = Zvfi
(Io)
dm = ~p
(II) Formula (5) may be employed as a check upon this. Throughout the whole series of measurements the length of b has been divided into equal distances.
In order to show the use of the simplified method worked out in II, we will now calculate the volume of the river, according to both methods, using the data afforded by four actual measurements. The constant k of the velocity instrument is 0.00930; multiplying by this coefficient, we reduce the values given here below for v/k, which indicate the number of revolutions in 3o seconds, to metres per second.
Fig. 36. Left. io April igoo. b = 30.o metres. n = ro Kum-tschapghan. Right.
p . . 0.68 I.i8 I.67 2.96 4.3o 4.93 5.09 4.33 0.87 metres
v/k . . 21.5 31.5 33.7 39.o 45.o 38.4 43.2 26.4 o I metre
k second
Fig. 35.
B
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