31036 - Hydraulics T

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. General principles.

Measure systems. Dimensional analysis and homogeneity. Buckingham (greek-pi) theorem. Scaled physical models.

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

Analysis and design of conduits and conduit networks in regime conditions. Flux control in plants and necessary conditions for a proper behaviour. Solution methods for the verification problem and relyability and econmiy criteria for an effective design.

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

Suggested:

H. Rouse. Elementary fluid mechanics. Ed Dover, 1946.
YA Cengel & JB Cinbala, Meccanica dei fluidi, McGraw-Hill, Milano, 2007.

Others:

A. Cenedese. Meccanica dei fluidi, McGraw-Hill 2003.
P.M. Gerhart & R.J. Gross. Fundamentals of Fluid Mechanics

Teaching methods

The course is composed of lectures, exercises and visit to laboratory.
Lectures will present principles, theoretical results and practical tools.  Class exercises will demonstrate applications of practical tools with numeric examples. During the visit(s) to laboratory experiences will be presented that are useful for the comprehension of theoretical and practical concepts.

Assessment methods

Two written verifications during the course, results valid for a session.  Oral examination is mandatory and simplified for those who passed the written test. In the written tests problems will be proposed similar to the class exercises and/or the presentation of a theoretical result. The problems will be presented in the classroom and the verification vill be done for both the class script and the home revision performed within one day.

Examination call will be opened in ALMA-Esami.

For the first session after the course one written test and two oral calls will be opened. Later one oral call every fourth week will be opened in periods allowed by the Faculty.

Teaching tools

Class lectures with auxiliary documents at the teacher web site.

Office hours

See the website of Alberto Lamberti

See the website of Renata Archetti