34773 - Maritime Hydraulics M

Learning outcomes

To provide the physical and technological background to evaluate the technical feasibility and effectivness of interventions for coastal defence and the tools for the design of these interventions with example applications to real cases.

Course contents

Wind classifications, Beaufort scale, statistics and climate.  Wind generation mechanism, perturbation, geostrofic approximation, velocity distribution in the planetary boundary layer.  Effects of winds, lift and drag on immersed bodies, shear on the earth or water surface.

Tide classification.  Astronomical tide, generation mechanism, components, record analysis, spring and neap tides, tidal regime classification.  Meteorological tide, response to pressure and to wind stress.  Static interpretation models.  Statistics of tidal level.  Conventional tidal levels.

Waves.  Linear irrotational wave theory.  Dispersion relation.  Velocity, pressure, trajectories.  Superposition principle.  Perfect and imperfect clapotis.  Wave groups.  Phase celerity and group velocity.  Mean Lagrangian velocity, mass transport, reference frames.  Energy density, energy transport.  Momentum density and transport.

Higher order approximations.  Breaking mechanisms and conditions, limit wave height in deep and shallow water, Miche equation.

Superposition of an infinite number of elementary components.  Energy spectrum.  Narrow band spectra, envelope amplitude, Rayleigh distribution of wave amplitude.  Wave records, empirical definition of wave height and period, occurrence frequency distributions of wave height and period, significant wave.  Time analysis of records, frequency analysis, characteristic parameters and relations among them.

Generation of wave by wind , work performed by pressure and by shear stress on the free surface, wave-wave interaction characteristics, evolution of wind-wave spectra, PM and JONSWAP spectra, practical relations for wind wave hind casting.  Fetch and duration limited conditions.  Geographical fetches, effective fetches, mean wave direction.

Wave propagation over gradually varying water depth : refraction approximation.  Ray equations.  Direct refraction, shoaling and refraction coefficients.  Inverse refraction.  Refraction of wave spectra, caustics.  Wave attenuation due to bottom friction.

Wave diffraction ,  special solutions, diffraction diagrams for isolated breakwaters and for entrances.  Asymptotic directional dispersion of diffracted waves.

Rubble mound breakwaters .  Construction techniques.  Breaker types, wave run-up and reflection on permeable slopes.  Stability of the armour layer, Hudson and van der Meer equations, stability of the toe berm, stability of crownwall, overtopping and wave transmission, rear side stability.  Filter rules and stability of the core.  Geotechnical stability of the foundation.  Settlement.

Surf zone hydrodynamics .  Wave breaking, wave set up, long shore currents for regular waves on a prismatic beach.  Effects of wave and beach irregularities.

Transversal equilibrium of the beach ,  Dean-Bruun profile, closure depth.  Breaker bars and time evolution of the profile.

Long shore sediment transport , evolution of the littoral as a 1-D system, Pelnard-Considère theory, particular solutions.

Groin systems, characteristic dimensions, effects, construction sequence.  Parallel emerging breakwaters, characteristic dimensions and effects.  Submerged breakwaters.  Revetments and dikes.

Beach nourishment , choice of materials, borrow areas and sand delivery systems.  Lifetime of a non protected finite length work.  Protected nourishments.

Readings/Bibliography

 Zanuttigh, B., 2006. Idraulica Marittima. edito da ALMA-DL Alma Mater Università di Bologna e depositato presso la BNCF. (http://amscampus.cib.unibo.it/archive/00002138/)

Coastal Engineering Manual http://users.coastal.ufl.edu/~mcdougal/CEM/CoastalEngineeringManual.htm

Burcharth, H. F., Hawkins, S. J., Zanuttigh, B. Lamberti, A. 2007. Environmental design guidelines of low crested coastal structures. Elsevier.

J.W. Kamphuis, Introduction to Coastal Engineering and Management, Adv. Series on Ocean Engineering – vol. 16, World Scientific 

R.G. Dean & R.A. Dalrymple, Water wave mechanics for engineers and scientists, Adv. Series on Ocean Engineering – vol. 2, World Scientific 

R.G. Dean & R.A. Dalrymple, Coastal Processes (with Engineering Applications), Cambridge University Press 

U. Tommasicchio, Manuale di Ingegneria portuale e costiera, Bios

Teaching methods

Lessons and excercises, visits in laboratory and in field

Assessment methods

Oral examination

Teaching tools

http://amscampus.cib.unibo.it/archive/00002138/

Office hours

See the website of Barbara Zanuttigh