1 Fundamentals of Hydraulic Physical Modelling.- 1. Introduction.- 2. Principles of the Theory of Dimensions.- 2.1. Dimensional and dimensionless quantities.- 2.2. Characteristic parameters.- 2.3. Dimensionless expression of a natural law.- 3. Principles of the Theory of Similarity.- 3.1. The idea of a model.- 3.2. Definition of dynamic similarity.- 3.3. Dynamically similar models and their scales.- 4. Hydraulic Models.- 4.1. General, conventional models (operating with water).- 4.2. Distortion.- 4.3. Froudian models.- 5. Further Approaches to Hydraulic Model Design.- 5.1. General.- 5.2. Examples.- 5.2.1. Inception of sediment transport.- 5.2.2. OTEC - Power plants (Ref. [9]).- 5.2.3. River flow with bed covered by sand waves.- 2 River Models.- 1. Non Maritime Models with Fixed Bed.- 1.1. Similarity for rivers and open channels.- 1.1.1. Undistorted models.- 1.1.2. Distorted models.- 1.2. Models of hydraulic structures.- 1.2.1. Similarity.- 1.2.2. Examples of hydraulic structures.- 1.2.2.1. Low-head hydraulic structures.- 1.2.2.2. Flood-discharge structures (weirs and spillways).- 1.2.2.3. Internal flow systems.- 1.2.3. Problems connected to air entrainment.- 1.2.3.1. Two-phase flow.- 1.2.3.2. Vortices.- 1.3. Mixing models.- 1.3.1. Turbulent entrainment at the effluent jet.- 1.3.2. Rise of the jet by buoyancy.- 1.3.3. Convective spread over the surface.- 1.3.4. Mass transport.- 1.3.5. Diffusion and dispersion.- 1.3.6. Loss of heat through surface.- 1.4. Models of flows without a free surface.- 1.5. Models of river training schemes.- 1.6. Model techniques.- 1.6.1. Construction.- 1.6.2. Control and operation.- 1.6.3. Calibration.- 1.6.4. Measurement and instrumentation.- 1.6.4.1. Flow velocities.- 1.6.4.2. Water levels.- 1.6.4.3. Water pressures.- 2. Sediment Transport in Rivers.- 2.1. Basic concepts and relevant parameters.- 2.1.1. The granular material.- 2.1.2. The flow: velocity distribution.- 2.1.2.1. Laminar zone y ?.- 2.1.3. Dimensional analysis of the two-phase phenomenon.- 2.2. Beginning of sediment transport - transport rate.- 2.3. Sand waves.- 2.3.1. If the flow is tranquil (Fr 1).- 2.4. Friction factor.- 2.5. Suspended load.- 3. River Models with Movable Bed.- 3.1. Model laws for bedload.- 3.1.1. Models with flat bed.- 3.1.2. Models with sand waves.- 3.1.2.1. Scaling of undistorted models.- 3.1.2.2. Scaling of distorted models.- 3.2. Modelling techniques.- 3.2.1. Construction.- 3.2.2. Choice of movable bed material.- 3.2.3. Calibration of the model.- 3.2.4. Operation and measurement.- 3.3. Case studies.- 3.3.1. The Rhône river near the confluence with the Drôme river.- 3.3.2. The Loire river near Orleans in France.- 3.4. Comparison with other modelling techniques.- 3.4.1. Aerodynamic models.- 3.4.2. Numerical models.- 3 Models for Study of the Dynamic Behaviour of Structures in Flow and Waves.- 1. Introduction in the Held of Hydro-Elasticity.- 2. The Single Resonator in a Flow Field.- 3. Response Calculations at Random Excitation.- 4. Introduction to Added Mass, Added Damping, Added Rigidity and Self-Excitation.- 4.1. Introduction.- 4.2. Introduction of added mass, added damping and added rigidity.- 4.3. Self-exciting vibrations of gates.- 4.4. The bathing plug equations.- 4.5. Application of theory to underflow type of gates.- 5. Models with Elastic Similarity for the Investigation of Hydraulic Structures.- 5.1. Hydraulic reproduction laws.- 5.2. Elastic properties of models.- 5.3. Combination for flow without free liquid surface.- 5.4. Combination for flow with free liquid surface.- 5.5. Model research and verification measurement on the Hagestein visor gates.- 5.6. Further application of elastic similarity models.- 6. The Use (Applicability and Limitations) of Physical Models in Vibration Research.- 6.1. Introduction.- 6.2. Types of physical models for vibration research.- 6.3. Air models for gate research.- 6.4. General remarks on the reliability of models.- 6.5. Particular scale effects of models with continuous elasticity.- 7. Interpretation of Results.- 8. Cavitation Research.- 9. Strategy for Vibrations-Free Design of Larger Gate Structures.- 10. New Developments in the Field of Modelling Hydro-Elasticity.- 4 Models for Study of the Hydrodynamic Actions on Hydraulic Structures.- 1. Introduction.- 1.1. General considerations.- 1.2. Formulation of the problem.- 2. Hydrodynamic Actions on Stilling Basins.- 2.1. General aspects.- 2.2. Theory and procedures for physical modelling of hydrodynamic actions.- 2.3. Evaluation of hydrodynamic actions on stilling basins.- 2.3.1. Method of global behaviour.- 2.3.2. Method based on direct measurement of F (t).- 2.3.3. Evaluation of hydrodynamic forces and moments by means of surface pressure measurements.- 2.3.3.1. General aspects.- 2.3.3.2. Evaluation of hydrodynamic actions.- 3. Dynamic Analysis.- 3.1. General considerations.- 3.2. Case studies.- 4. Hydraulic Modelling of Hydrodynamic Actions.- 4.1. Formulation of the problem. Similarity laws.- 4.2. Air entrainment on chutes and overflow spillways.- 4.3. Mean pressures on ski jumps.- 4.4. Free falling turbulent jets through the atmosphere.- 4.5. Diffusion of plunging turbulent jets in a pool. Effects on the dynamic pressures.- 4.6. Statistical parameters of pressure field. Scale effects.- 5 Density Models.- 1. Introduction.- 1.1. Definition.- 1.2. Historical background.- 1.3. Unique aspects.- 1.4. Advantages of physical models.- 1.5. Scope of paper.- 2. Modelling Principles.- 2.1. General.- 2.2. Similitude requirements.- 3. Scale and Boundary Effects.- 3.1. Definition of scale effects.- 3.2. Minimizing scale effects.- 3.3. Boundary effects.- 3.4. Procedures.- 3.4.1. Cooling tower studies.- 3.4.2. Dense gas releases.- 3.5. Use of stratified flow flumes.- 4. Limitations.- 4.1. Physical understanding.- 4.2. Multiple flow regime conflicts.- 4.3. Model restrictions.- 4.4. Model costs.- 5. Model Specifications.- 5.1. Scale.- 5.2. Boundary conditions.- 5.3. Characteristics of receiving waters.- 5.4. Characteristics of effluent.- 5.5. Test procedures.- 5.6. Sensitivity tests.- 5.7. Calibration.- 6. Applications.- 6.1. Outfalls.- 6.2. Estuary models.- 6.3. Density current models.- 6.4. Reservoir/cooling pond models.- 6.5. Accidental release models.- 6.6. Cooling tower models.- 6.7. Porous media models.- 6.8. Internal waves models.- 6.9. Sedimentation models.- 6.10. Other models.- 7. Case Studies.- 7.1. Diablo canyon model studies.- 7.2. Tailings discharge studies.- 7.3. Buoyant discharges into stagnant rivers.- 6 Tidal Models.- 1. Introduction.- 1.1. General.- 1.2. Fundamentals of tidal motion.- 2. Model Laws.- 2.1. General.- 2.2. Fixed bed models.- 2.3. Movable bed models.- 2.4. Wave-current interaction.- 3. Boundary Conditions.- 4. Operation of Tidal Models.- 4.1. General.- 4.2. Tide generation.- 4.3. Currents. Fluvial discharges.- 4.4. Model sediments.- 4.5. Calibration.- 4.5.1. Fixed bed models.- 4.5.2. Movable-bed models.- 5. Instrumentation. Data Acquisition and Model Control.- 5.1. General.- 5.2. Data acquisition.- 5.2.1. Tidal levels.- 5.2.2. Currents.- 5.2.3. Bottom surveying.- 5.3. Data analysis.- 5.4. Automatic control.- 5.4.1. The control unit.- 5.4.2. Control of operation instruments.- 5.4.3. Data acquisition.- 5.4.4. The need for instrument calibration.- 6. Case Studies.- 7 Hybrid Modelling as Applied to Hydrodynamic Research and Testing.- 1. Introduction.- 2. The Design of the Demonstration Hybrid Model.- 2.1. The mathematical model of the entire estuary.- 2.2. The structure of the control interval.- 2.3. The hybrid model simulation.- 2.3.1. Variation of the control interval.- 2.3.2. Application of Q-values.- 2.3.3. The effect of noise and cross-modes.- 3. The Construction of the Demonstration Hybrid Model.- 3.1. The physica…