BS ISO 4377:2012
$198.66
Hydrometric determinations. Flow measurement in open channels using structures. Flat-V weirs
| Published By | Publication Date | Number of Pages |
| BSI | 2012 | 70 |
This International Standard describes the methods of measurement of flow in rivers and artificial channels under steady or slowly varying conditions using flat-V weirs (see Figure 1).
Annex A gives guidance on acceptable velocity distribution.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 9 | 1 Scope 2 Normative references |
| 10 | 3 Terms and definitions |
| 11 | 4 Symbols |
| 12 | 5 Characteristics of flat-V weirs 6 Installation 6.1 Selection of site |
| 15 | 6.2 Installation conditions 6.2.1 General requirements 6.2.2 Approach channel |
| 16 | 6.3 Weir structure 6.4 Downstream conditions 7 Maintenance |
| 17 | 8 Measurement of head(s) 8.1 General 8.2 Stilling (gauge) wells |
| 19 | 8.3 Zero setting |
| 21 | 8.4 Location of head measurement sections |
| 22 | 9 Discharge relationships 9.1 Equations of discharge |
| 23 | 9.2 Effective heads |
| 24 | 9.3 Shape factors 9.4 Coefficient of velocity |
| 26 | 9.5 Conditions for modular/drowned flow |
| 29 | 9.6 Drowned flow reduction factor |
| 36 | 9.7 Limits of application |
| 37 | 10 Computation of discharge 10.1 General 10.2 Successive approximation method 10.2.1 Computation using individual head measurements |
| 38 | 10.2.2 Computation of modular stage-discharge function |
| 39 | 10.3 Coefficient of velocity method 10.3.1 Modular flow conditions 10.3.2 Drowned flow conditions |
| 40 | 10.4 Accuracy 11 Uncertainties in flow determination 11.1 General |
| 41 | 11.2 Combining uncertainties |
| 42 | 11.3 Uncertainty in the discharge coefficient u*(CDe)68 for the flat-V weir 11.4 Uncertainty in the drowned flow reduction factor u*(Cdr) |
| 43 | 11.5 Uncertainty in the effective head 11.6 Uncertainty budget |
| 44 | 11.7 Variation of uncertainty with flow and uncertainty in mean daily flow and the daily flow volume 11.7.1 Uncertainty curve |
| 45 | 11.7.2 Uncertainty in the daily mean flow 11.7.3 Uncertainty in the daily flow volume 12 Examples 12.1 Example 1 — Computation of modular flow at low discharge 12.1.1 Data |
| 46 | 12.1.2 Solution by successive approximation method (see 10.2) |
| 47 | 12.1.3 Solution by coefficient of velocity method (see 10.3) 12.2 Example 1 — Uncertainty in computed discharge 12.2.1 Uncertainty in the discharge coefficient 12.2.2 Uncertainty in drowned flow reduction factor 12.2.3 Uncertainty in the horizontal; component of the weir crest gradient 12.2.4 Uncertainty in the effective total head |
| 48 | 12.2.5 Overall uncertainty |
| 49 | 12.3 Example 2 — Computation of drowned flow at high discharge 12.3.1 Data 12.3.2 Solution using successive approximation method (see 10.2) |
| 50 | 12.3.3 Solution using the coefficient of velocity method (see 10.3) |
| 51 | 12.4 Example 2 — Uncertainty in computed discharge 12.4.1 Uncertainty in the discharge coefficient 12.4.2 Uncertainty in the horizontal; component of the weir crest gradient 12.4.3 Uncertainty in the effective total head |
| 52 | 12.4.4 Uncertainty in the separation pocket (crest tapping) head 12.4.5 Uncertainty in drowned flow reduction factor 12.4.6 Overall uncertainty for non-modular flow example |
