Abstract

Dam bottom outlets play a vital role in dam operation and safety, as they allow controlling the water surface elevation below the spillway level. For partial openings, water flows under the gate lip at high velocity and drags the air downstream of the gate, which may cause damages due to cavitation and vibration. The convenience of installing air vents in dam bottom outlets is well known by practitioners. The design of this element depends basically on the maximum air flow through the air vent, which in turn is a function of the specific geometry and the boundary conditions. The intrinsic features of this phenomenon makes it hard to analyse either on site or in full scaled experimental facilities. As a consequence, empirical formulas are frequently employed, which offer a conservative estimate of the maximum air flow. In this work, the particle finite element method was used to model the air–water interaction in Susqueda Dam bottom outlet, with different gate openings. Specific enhancements of the formulation were developed to consider air–water interaction. The results were analysed as compared to the conventional design criteria and to information gathered on site during the gate operation tests. This analysis suggests that numerical modelling with the PFEM can be helpful for the design of this kind of hydraulic works.

Abstract

4 Air demand modelling: overview and application to a developing regional airport M. Nadia Postorino University ‘Mediterranea’ of Reggio Calabria, Italy Abstract Air demand forecast at airports is animportant problem for the airport management and also for the regulator that has to plan a homogeneousdevelopment of the overall transport system. The current tendency is towards airport privatization; then, the goal to increase the served demand is one of the most important together with the progress of non-aviation activities. The evolution of the air transport system both in terms of low-cost companies, thatgenerally use regional airports, and new technologies (as regional jets) has given a further impulse to the development of planning methodologies able tosupportdecisions for an efficient distribution of resources. Regional airports can play an important role in this new background if the most suitable developing strategiesare identified. This chapter wants togive a generaloverview about the problemof the air demand modelling, both in terms of theoretical approaches andpractical problems. Models are classified with respect todifferent criteria, and the most suitable models for eachplanning level are also identified.Anapplication toa regional airport inSouthern Italy is also presented in order to testsome of the described approaches and to obtainpractical indications aboutapplied models and developing strategies tobe used.