Scientific Sector ICAR/01 Hydraulics
Number of University Credits 6
Educational Goals The course of Maritime Hydraulics is for students of the second degree in Environmental Engineering. The course aims to provide the basics of the hydrodynamics for the solution of problems related to wave mechanics. These elements are fundamental for the analysis of beach erosion and coastal risks near river mouths or estuaries, particularly sensitive and important for the environment preservation. The course presents also elements of the design of coastal protection systems, analyzing the different types and identifying their typical strengths and weaknesses, elements on the wastewater diffusion into the sea, design of a diffuser and modeling of refraction, diffraction and sediment transport using a software.
Summary of the program WAVE MECHANICS
Regular waves. Basics of wave mechanics. Small amplitude wave theory. Wave reflection, refraction, diffraction and breaking.
Irregular waves. The statistical parameters of irregular waves.
WAVE PREDICTION
Wave climate of a sea area. Estimation of surface winds for wave prediction. Simplified methods for estimating wave conditions. Wave forecasting for deep waters.
STRUCURAL DESIGN
Basics of coastal defense structures. Seawalls and breakwaters design.
Wastewater diffusion into the sea.
Momentum and buoyant jets. Submarine pipes and diffusers. Diffuser design criteria.
Design.
REFRACTION DIAGRAM CONSTRUCTION
WASTWATER DIFFUSION INTO THE SEA
Momentum and buoyant jets. Submarine pipes and diffusers. Diffuser design.
MODELLING OF REFRACTION, DIFFRACTION AND SEDIMENT TRANSPORT WITH A SOFTWARE
Structure in different typological educational activities
| Educational activities |
Credits
|
Didactics (hours)
|
Studying (hours)
|
| Theoretical classes |
4
|
32
|
68
|
| Exercises |
1
|
16
|
9
|
| Laboratory training |
1
|
24
|
1
|
| Total |
6
|
72
|
78
|
Final examination The final exam of Maritime Hydraulics is composed of:
1) Oral test on the theoretical part of the course.
2) Homework on the refraction diagram construction.
During the classes two written tests (exemptions from the oral test) will be proposed to the students who attend the lessons (on both the theory and exercises). The students that pass these two tests will be successively examined orally on the homework on the refraction diagram construction. In case of fail of one or more of the exemption tests (also for absence), the students will be examined orally also on the relating part.
Detailed program of the course WAVE MECHANICS
Wave representation in the time and frequency domain. Classification of waves. Theory of Airy. Wave height, length and period. Wave elevation. Celerity of a wave. Deep, intermediate and shallow waters.
Pressure distribution with the theory of Airy. Orbital wave velocities: deep, intermediate and shallow waters. Esercises of wave mechanics.
Wave group and celerity. Reflection of a wave. Total reflection (clapotis). Standing waves. Reflection caused by a vertical sea-wall and a breakwater; reflection from a bathymetric variation and from bars at the sea bottom. Energy of a wave and energy flux. Shoaling and refraction coefficients. Wave breaking. Breaking wave diagrams of Goda.
Exercises on the wave breaking. Diffraction. Diagrams of Wiegel and Johnson. Exercises on the diffraction. Beaufort wind scale Douglas sea scale. Wind rose. Typical wind data provided by ENAV.
Geographical and effective fetch. Wind direction, velocity and duration. SMB diagram; fetch-limited and duration-limited cases. Significant height and period, wave spectrum and peak period. Tenani method for Refraction diagram construction
Characteristics of ocean waves: statistical propriety and typical spectra. Types of harbors, port systems access to a port. Typical examples of coastal defense structures. Design of vertical seawalls using the criteria of Goda. Breakwaters. Formula of Hudson and stability number of Hudson. Exercises on the coastal defense structures.
WASTWATER DIFFUSION INTO THE SEA
Basics on the differential and integral equations of mass conservation and momentum.
Basics on the turbulence.
Jet classification. Pure jets: differential equation of the momentum and general description of the flow field.
Entrainment. Compound momentum jets. Buoyant jets and plume. Typical length scales. Dimensional analysis for jets. Densimetric Froude number.
General description of submarine pipes. Dilution. Wastewater treatment and rules. Near and far fields. Hydraulic characteristics of the jets. Head losses in a diffuser. Energy grade line in a diffuser. Design of a diffuser. Typical forces on a submarine pipe: Morison and lift forces.
MODELLING OF REFRACTION, DIFFRACTION AND SEDIMENT TRANSPORT WITH A SOFTWARE
Refraction diagram description.
Maritime charts. Notes on: 1) refraction index, 2) diffraction, 3) design wave height in deep water, 4) direct methods, 5) indirect methods, 6) return period, 7) geographic and effective fetch. Digitization of a chart, coastline and bathymetric lines. Mathematical model DHI-MIKE. Overview of the software MIKE. Example of use of MIKE 21 to study the propagation of a wave. Wave spectra and wave generation area. Jonswap and Pierson-Moskowitz spectra. Evolution processes of a coastline and wave theories of higher orders. Dean’s equilibrium profiles of sand bottom.
Recommended books 1) Course notes.
2) CERC, Shore Protection Manual.
3) Wood, I.R., Bell, R.G., and Wilkinson, D.L., 1993. Ocean disposal of wastewater, World Scientific, Advanced Series on Ocean Engineering, Vol. 8.
4) W. Bascom, Waves and beaches, Anchor Science Study Series.
5) L. Franco, Manuale di Idraulica Marittima, Ormea (in Italian).
LIC - Coastal Engineering Laboratory
2446
