Papers by Renata Della Morte
Water Science & Technology: Water Supply, 2015
Nel presente lavoro viene proposta una metodologia per l’individuazione della posizione e del set... more Nel presente lavoro viene proposta una metodologia per l’individuazione della posizione e del settaggio ottimale di un preassegnato numero di valvole di riduzione della pressione da inserire all’interno di una rete di distribuzione idrica al fine di regolare l’andamento delle quote piezometriche. Pur rispettando i vincoli imposti sulle quote piezometriche, e tali da garantire il servizio all’utenza, la regolazione è effettuata in modo da ottenere una riduzione delle sollecitazioni a cui sono sottoposte le condotte e delle perdite di acqua nel sottosuolo che si realizzano nel corso della giornata. L’ubicazione ed il settaggio ottimale delle valvole vengono determinati mediante l’applicazione di un algoritmo genetico: la funzione obbiettivo utilizzata nella procedura di ottimizzazione è costituita dalla somma dei costi economici e sociali legati alle perdite idriche (qui identificati, a solo titolo esemplificativo, nel mancato beneficio per il gestore) e del costo di realizzazione e d...
The treatment of advective fluxes in high-order finite volume models is well established, but thi... more The treatment of advective fluxes in high-order finite volume models is well established, but this is not the case for diffusive fluxes, due to the conflict between the discontinuous representation of the solution and the continuous structure of analytic solutions. In this paper, a Derivative Reconstruction approach is proposed in the context of Spectral Volume methods, for the approximation of diffusive fluxes, aiming at the reconciliation of this conflict. The method is demonstrated by a number of numerical experiments, including the solution of Shallow-water Equations, complemented with the advective-diffusive transport equation of a conservative dissolved substance.
Journal of Irrigation and Drainage Engineering, 2015
ABSTRACT The present work describes a procedure for the evaluation of the optimal number, positio... more ABSTRACT The present work describes a procedure for the evaluation of the optimal number, position, configuration, and sizes of detention tanks in urban drainage networks, to decrease the maximum flow depths and velocities for an assigned return period and to comply with the local design requirements. Each candidate solution of the optimization problem is evaluated by means of a semidistributed hydrological model in which the kinematic wave is used as flood routing model, whereas the variational approach is used to evaluate the critical flow characteristics corresponding to a given return period. The procedure, which makes use of a genetic algorithm to search for the optimal solution among the candidates, is applied to a case study drainage network, considering superpipe-based detention tanks as detention systems. The results indicate that these tanks are effective in the rehabilitation of the drainage network and that the cost of this intervention is substantially lower than that corresponding to the upgrading of existing pipes.
Journal of Applied Water Engineering and Research, 2015
ABSTRACT Sideweirs are hydraulic structures commonly used in combined sewer systems for separatin... more ABSTRACT Sideweirs are hydraulic structures commonly used in combined sewer systems for separating excess storm water from urban sewage. In the case of low-crested sideweirs, the design is difficult because supercritical flows may establish along the overflow reach. This can lead to transcritical conditions not easily modelled in many cases. The present paper analyses the supercritical outflow process over a low-crested bilateral sideweir in a circular channel, based on both experimental and numerical investigations. Experiments were conducted to define the approach water depth and the free-surface profiles. The measurements were compared with the numerical values resulting from the application of energy and momentum conservation principles. The paper shows that the formulas used for estimating the end depth at free overfalls in circular channels can be applied to evaluate the approach water. The numerical investigation proves that the energy conservation approach allows for the computation of free-surface profiles with reasonable accuracy.
Advances in Water Resources, 2015
The general solution of the dam-break problem with partial uplift of the sluice-gate is presented... more The general solution of the dam-break problem with partial uplift of the sluice-gate is presented in the framework of the one-dimensional Shallow-Water Equations, under the hypothesis that the classic Energy-Momentum (E-M) formulation is used to evaluate the flow characteristics at the gate. Due to the nonlinearity of the problem, there are ranges of the initial conditions for which the problem admits multiple solutions, or no solution. In the ranges in which there are multiple solutions, the maximization of the discharge under the gate is used as a disambiguation criterion. The exact solutions are used as a benchmark in order to evaluate the results of a simple Finite-Volume scheme, where the discharge under the gate and the forces exerted on the flow by the gate itself are calculated using the E-M formulation.
Water Resources Research, 2015
Simplified flood propagation models are often employed in practical applications for hydraulic an... more Simplified flood propagation models are often employed in practical applications for hydraulic and hydrologic analyses. In this paper, we present a new numerical method for the solution of the Linear Parabolic Approximation (LPA) of the De Saint Venant equations (DSVEs), accounting for the space variation of model parameters and the imposition of appropriate downstream boundary conditions. The new model is based on the analytical solution of a cascade of linear diffusive channels in the Laplace Transform domain. The time domain solutions are obtained using a Fourier series approximation of the Laplace Inversion formula. The new Inverse Laplace Transform Diffusive Flood Routing model (ILTDFR) can be used as a building block for the construction of real-time flood forecasting models or in optimization models, because it is unconditionally stable and allows fast and fairly precise computation.
Procedia Earth and Planetary Science, 2014
The paper describes the development and the assessment of a numerical model for the simulation of... more The paper describes the development and the assessment of a numerical model for the simulation of debris flow phenomena. Aiming at this, after having considered the causes of triggering, this work focuses on the simulation of propagation characteristics of the masses mobilized, taking into account both the actual internal dissipative processes characterizing the sediment-water mixture and the effects induced by the modification of the boundaries where the flow takes place. The propagation model implemented is based on the one-dimensional hyper-concentrated shallow flows equations, suitable to take into account also the solid and fluid mass exchanges with the bottom. This system of non-linear partial differential equations is integrated by means of a one-dimensional finite volume scheme, second-order accurate in space and time. In order to show the performance and capabilities of the model, the results of its application to a laboratory dam-break experiment are analysed, and finally the application to a real-world test-case is discussed.
Journal of Hydroinformatics, 2014
ABSTRACT The broad-crested weir can be regarded as a zone of rapid variation of the bottom elevat... more ABSTRACT The broad-crested weir can be regarded as a zone of rapid variation of the bottom elevation that is short with respect to the characteristic length of the considered domain, and for this reason it can be conceptually modelled as a bed step. In this paper, the solution of the Riemann problem for the shallow-water equations over a bed step is exploited in order to simulate the behaviour of the broadcrested weirs, when these are present at the boundaries of the numerical domain. The issue of the multiplicity of solutions for this special Riemann problem is discussed, and rules are given in order to pick up the congruent solution among the alternatives. Finally, the proposed approach is implemented into a finite volume model for the approximate solution of one-dimensional shallowwater equations. Several numerical tests are carried out in order to demonstrate its possibilities and promising capabilities.
A broad-crested weir boundary condition in finite volume shallow-water numerical models
In the literature, the weir boundary condition is usually implemented imposing the weir formula a... more In the literature, the weir boundary condition is usually implemented imposing the weir formula at the boundaries, but this is rigorous only in subcritical steady conditions, and a more general approach is required during transients. With acceptable approximation, the non-submerged broad-crested weir behaves as a bottom step where the energy is conserved and critical conditions are attained at the top. Taking advantage of this observation, the analytic solution of the Riemann problem for the Shallow-water Equations over a dry bottom step is considered in this paper, and the momentum and mass fluxes of the analytic solution of the Riemann problem are used to impose weakly the broad-crested non-submerged weir boundary condition in a Finite Volume scheme.
Journal of Irrigation and Drainage Engineering, 2014
ABSTRACT The discharges flowing through rural drainage networks depend not only on the local clim... more ABSTRACT The discharges flowing through rural drainage networks depend not only on the local climatic and hydrologic characteristics, but also on the geometric characteristics of the channels constituting the network. For this reason, the evaluation of the design discharges should be accomplished during the search of the optimal network. This leads to time-consuming optimization procedures, and it is desirable to devise efficient numerical alternatives. Two novel models, EGA and EGA-f, are proposed in order to increase the numerical efficiency of Genetic Algorithms for the solution of the optimal rural drainage network problem. Both EGA and EGA-f procedures are based on the use of the nodal excavation depths at the channel ends as decision variables Moreover, the EGA-f procedure improves EGA by freezing temporarily the design discharges during the optimization process in the case that uniform flows through the channels can be assumed. The application of the two models is demonstrated by means of numerical experiments, confirming their superiority over existing Genetic Algorithms for the optimization of rural drainage networks.
Journal of Hydroinformatics, 2013
In this paper the main features and performances of a new numerical scheme, ILILPM (Improved Loca... more In this paper the main features and performances of a new numerical scheme, ILILPM (Improved Locally and Instantaneously Linearized Parabolic Model) are described. ILILPM is an improved version of the Parabolic and Backwater (PAB) and Linearized Parabolic Model (LPM) schemes, proposed in literature for the approximate solution of the Parabolic Wave model. The algorithm presented is able to take into account transcritical flow regime and transitions from free-surface to pressurized flow in tree-like channel networks. Due to its unconditional stability, the model allows large computational time steps, leading to very fast simulations during transients for a class of flow conditions larger than those solved by the parent schemes. The model is demonstrated by comparing its results with experimental observations and with the results provided by the numerical solution of the full De Saint-Venant equations.
Journal of Hydraulic Engineering, 2014
ABSTRACT The numerical modelling of hyperconcentrated shallow flows is a challenging task because... more ABSTRACT The numerical modelling of hyperconcentrated shallow flows is a challenging task because they exhibit special features, such as propagation over dry bed, profound bed elevation modifications due to erosion or deposition phenomena, and flow discontinuities. In this paper, a novel depthpositivity preserving HLLC Riemann solver is devised in order to approximate the solution of the Riemann problem for the one-dimensional Hyper-concentrated Shallow Flows equations over horizontal bed. The solver is used as a building block for the construction of HCSF, a wellbalanced Finite Volume scheme for the solution of the Hyperconcentrated Shallow Flows equations with variable elevation. HCSF is able to handle the case of dry bed, to take into account the variability of the topography also in presence of bed discontinuities, considering the flow resistance and the mass exchange between the flowing mixture and the mobile bed. The numerical tests carried out confirm the well-balancing property of the scheme proposed, the robustness in presence of dry bed, the ability to approximate the analytic solution of problems with smooth or discontinuous bed, and the ability to reproduce reasonably the results of a laboratory experiment.
Civil Engineering and Environmental Systems, 2011
Water distribution systems are vulnerable to intentional contamination: in this paper, optimising... more Water distribution systems are vulnerable to intentional contamination: in this paper, optimising the placement of a set of monitoring stations to promptly detect this type of attack is considered. Due to the uncertainty about the place and the time of the beginning of the ...
Advances in Water Resources, 2014
Please cite this article as: Cimorelli, L., Cozzolino, L., Della Morte, R., Pianese, D., Analytic... more Please cite this article as: Cimorelli, L., Cozzolino, L., Della Morte, R., Pianese, D., Analytical solutions of the linearized parabolic wave accounting for downstream boundary condition and uniform lateral inflows, Advances in Water Resources (2013), doi: http://dx.Abstract In this paper, new analytical solutions of the linearized parabolic approximation (LPA) of the De Saint Venant equations (DSVEs) are derived for the case of finite channel length. The new solutions, which take into account upstream and lateral inflows, are found considering two types of boundary conditions at the downstream end, namely a stage-discharge relationship and a time dependent flow depth. The solutions, for both discharge and water depth, are first determined in the Laplace Transform domain, and the Laplace Transform Inversion Theorem is used in order to find the corresponding time domain expressions. Finally, the effects induced on the flow propagation by the downstream boundary condition are analyzed using the new analytical solutions.
Journal of Hydroinformatics
The shallow-water equations are widely used to model surface water bodies, such as lakes, rivers ... more The shallow-water equations are widely used to model surface water bodies, such as lakes, rivers and the swash zone in coastal flows. Physically congruent solutions are characterized by nonnegative water depth, and many numerical methods may fail to preserve this property at the discrete level when moving wet–dry transitions are present in the physical domain. In this paper, we present a spectral-volume method for the approximate solution of the one-dimensional shallow-water equations, which is third-order accurate in wet regions, far from discontinuities, and which is well balanced for water at rest states: the stability of the solution is ensured if reconstruction and limitation of variables preserves non-negativity of the depth and a suitable constraint for the time step length is satisfied. A number of numerical experiments are reported, showing the promising capabilities of the model to solve problems with non-trivial topographies and friction.
Journal of Hydraulic Engineering, 2004
Journal of Hydraulic Engineering, 2004
Uploads
Papers by Renata Della Morte