CE320. Hydraulics II (ects: 7)
THEORY
Introduction in free surface ("open channel") flow. Basic differences between pressure flow ("closed pipe" flow) and free surface flow ("open channel" flow). Geometric and hydraulic characteristics of open channel flows; types of open channel flow (constant, transient, uniform).
Balance of hydraulic energy per unit weight. The Bernoulli equation and its application. Specific energy. Critical flow depth. The Froude number. Subcritical, critical and supercritical flows. Implementation of the specific energy: (a) change of specific energy under constant flowrate (b) flow with varying flow depth and/or varying channel width under constant total hydraulic energy.
Linear momentum balance and its application in the study of free surface flows. Hydraulic jump. Characteristics of hydraulic jump (energy dissipation, types of jumps, jump length). Celerity. Flow resistance in open channels. Flow resistance calculations in engineering practice (Chezy, Ganguillet & Kutter, Bazin, Darcy, Strickler, Manning). Basic problems of free surface flow. Control of open channel flows.
Uniform flows; characteristics and basic equations; basic channel design principles; optimum open channel cross-sections.
Gradually varied flows; basic equations, solutions, computation of flow profile.
Rapidly varied flows; basic equations; control devices for open channel flow: sluice gates, weirs, siphons, step transitions (upward/downward), settling basins.
Dimensional analysis, models and characteristic numbers.
LABORATORY
The laboratory part comprises a set of so called "lab exercises", whereby, basic hydraulic phenomena are reproduced, observed and analysed under controlled laboratory conditions in "lab classes".
Each laboratory exercise is deployed as follows: basic theoretical analysis of examined phenomenon; description of specific apparatus; laboratory reproduction; identification/description of the prevailing phenomena and mechanisms; data capture (measurements); data analysis; reconstitution of the transfer function of the phenomenon. Each student prepares a short essay with computations, results, remarks, observations, comments and conclusions.
At the end of the semester, students undergo a short written examination.
The set of laboratory exercises is as follows:
1. Simultaneous reproduction of uniform, gradually- and rapidly- varied flow along a 6m model flume
2. Study of the specific energy - flow depth relation under fixed flowrate conditions. Critical flow.
3. Study of hydraulic jump characteristics for various values of the Froude number.
4. Study of open channel flow through sluice-gate
5. Study of open channel flow over broad crested and sharp crested weirs
6. Study of open channel flow over step transitions, column pillars etc
7. Study of free surface wave velocity - Celerity
8. Open channel flow control using different devices (weirs, sluice gates etc)
9. Calibration of various types of weirs (V-notch, orthogonal, trapezoidal etc)
10. Use of Parshal plume in flowrate measurement
11. Velocity distribution in free surface flow (comparison between theoretical predictions and measured values)
12. Measurement of flow resistance in open channel flow and determination of friction coefficient using interchangeable roughness-surfaces on flume bed/walls
13. Dimensional analysis - typical similarity models
14. Final written examination