23330 - Hydraulics (l-Z)

Learning outcomes

Basic knowledge of fluid mechanics and hydraulics necessary to the following professional courses.  Students shall be able to carry out the basic design and verification of simple free surface or pressurized systems, considering the usual stationary flow conditions as well as extreme condition deriving from non stationary flows.

Course contents

Technical problems related to fluids, flow description and mechanical properties of fluids.

Measure systems. Dimensional analysis and homogeneity. Buckingham (greek-pi) theorem.
Velocity.  Stream lines and function. Vorticity and velocity potential. Local and convective time derivative and acceleration. Transport theorem. Continuity equation.

Volume and superficial forces.  The stress tensor and the perfect fluid.  Momentum balance equation.  Hydrostatics, barotropic condition, pressure distribution and forces, floaters.  Kelvin and Bernouilli theorems.  Heads.  Mechanical energy balance.  Pressure distribution in irrotational flow.

Unidimensional flow: quasi equivalence between momentum and energy balance principles.

Viscous reaction to deformation. Pressure drop in a permanent uniform flow of a viscous fluid. Energy dissipation due to viscosity. Reynolds number, instability of laminar viscous flow, qualitative properties of turbulence.

Boundary layer and flow separation. Pressure distributionon obstacles and wake resistance. Head losses in conduits transitions.

Superficial friction resistance. Velocity distribution near smooth and rough walls. Flow resistance in smooth, artificially roughened and naturally rough conduits.

Pelton turbine.  Propeller characteristics.  Axial flow and radial flow machinery.  Machine similitude and characteristic numbers. Cavitation and NPSH

Evaluation of regime conditions and design of conduits and networks.

Molecular attraction, superficial tension, capillarity and related effects. 

Mass oscillations, establishment of regime conditions.  The effect of compressibility. Propagation of elastic waves along conduits. Sudden, fast and slow flow control.

Gradually varied free surface streams.  The critical flow and stream classification.  Effects of a short variation of the channel section.  Backwater profiles. Hydraulic jump.

Unsteady flow of free surface streams.  Inertial waves and the method of characteristics.  Ritter solution to the dam-break problem.  Kinematic approximation, flood wave celerity. Uniformly progressive waves and wave profile near the tip.

Readings/Bibliography

H. Rouse. Elementary fluid mechanics. Ed Dover, 1946.
Citrini & Noseda. Idraulica. Ed. Ambrosiana, Milano, 1987.

YA Cengel & JB Cinbala, Meccanica dei fluidi, McGraw-Hill, Milano, 2007.

A. Cenedese. Meccanica dei fluidi, McGraw-Hill 2003.
A. Ghetti. Idraulica Ed. Cortina Padova, 1977.
V.L. Streeter. Fluid mechanics. Mc Graw Hill 1951.
P.M. Gerhart & R.J. Gross. Fundamentals of Fluid Mechanics

Teaching methods

Lessons, exercise classes and visits to the laboratory.

During lessons the principles and the main theoretical results are presented.  Exercise classes are dedicated to present practical applications with numerical results.  During laboratory visits the main experiments are presented useful for the practical comprehension of the main theoretical results.

Assessment methods

Optional written tests during course; optional make-up test at the first session after the course.  Mandatory oral session, simplified to students who passed the written test.  In written tests problems similar to those solved in the exercise classes will be required and/or the description of some main theoretical result.

Sessions- Apply through UNIWEX

First season after the course: two oral and one written sessions . During the rest of the year: one oral session every second week durino periods allowed by the faculty.

Teaching tools

Lessons and classes. Auxiliary material can be obtained through the web at the teacher site.

Office hours

See the website of Alberto Lamberti