Michele Iervolino

Università degli Studi della Campania "Luigi Vanvitelli · Dipartimento di Ingegneria

This paper presents the head-drop method for the modeling of pressure regulation devices in the steady-state simulation of water distribution networks (WDNs). The method is based on addition of device-associated head drops to the source term of pipe energy-balance equations. Head drops and device statuses (active, open, and closed) are updated duri...

Mud flows represent one of the major causes of natural hazards in mountain regions. Similarly to debris flows, they consist of a hyper-concentrated mixture of water and sediments flowing down a slope and may cause serious damages to people and structures. The present paper investigates the force produced by a dam-break wave of mud impacting against...

This paper presents a novel algorithm with improved convergence and robustness for the pressure-driven modelling of water distribution networks (WDNs), to be implemented as hydraulic engine in the fourth release of the SWANP software. The innovative approach is based on increasing the order of convergence, which is quadratic for algorithms obtaine...

Simplified versions of the Shallow Water Equations, known as Kinematic and Diffusive models, are commonly applied to the analysis of debris- and mud- flow dynamics. For this reason, the study of their applicability conditions represents an important concern. The present work investigates on the applicability conditions of the Diffusive Wave Model (...

The evaluation of the impact force on structures due to a flood wave is of utmost importance for estimating physical damage and designing adequate countermeasures. The present study investigates, using 2D shallow-water approximation, the morphodynamics and forces caused by a dam-break wave against a rigid obstacle in the presence of an erodible bed...

The 2D shallow water equations are often solved through finite volume (FV) methods in the presence of irregular topography or in non-rectangular channels. The ability of FV schemes to preserve uniform flow conditions under these circumstances is herein analysed as a preliminary condition for more involved applications. The widely used standard Hart...

The flow between two parallel plates driven by a pulsatile pressure gradient was studied analytically with a second-order velocity expansion. The resulting velocity distribution was compared with a numerical solution of the momentum equation to validate the analytical solution, with excellent agreement between the two approaches. From the velocity...

The Kinematic Wave Model (KWM), representing a simplification of the Full Wave Model (FWM) under the shallow-water approximation, is still used for predicting flood propagation requiring a reduced computational effort and for being more easily coupled with high-resolution topographic data. It is as suitable approach also for predicting debris and m...

The Kinematic Wave Model (KWM), representing a simplification of the Full Wave Model (FWM) under the shallow-water approximation, is often used in the one-dimensional formulation for describing the dynamics of debris/mud flood. The present work investigates the applicability conditions of the KWM to analyze mud floods, characterized by a rheologica...

The stability of the steady uniform flow of a power–law fluid down an inclined porous layer heated from below is investigated by means of a two–layer model. Under the long-wave approximation, the flow model is deduced starting from the continuity and momentum equations in the fluid film, the continuity and the generalized Darcy’s law in the porous...

Because of climate change, flood-prone areas are more and more frequently exposed to potential casualties and damage. The capability of the flow to carry relevant quantities of sediments during these critical events adds to the further complexity of the resulting scenarios. The interaction between the flow and the obstacles in flood-inundated areas...

The study of the interaction of mud-flows with obstacles is important to define inundation zones in urban areas and to design the possible structural countermeasures. The paper numerically investigates the impact of a mud-flow on rigid obstacles to evaluate the force acting on them using two different depth-integrated theoretical models, Single-Pha...

Climate change is exposing more and more frequently flood prone areas to potential casualties and damages. The capability of the flow to carry relevant quantities of sediments interacts with the presence of obstacles in flood-inundated areas and contributes to the increase the related hazard, constituting a relevant concern in the framework of risk...

A two–sided model is proposed to investigate the stability problem of the steady uniform flow of a power–law fluid layer down an inclined porous layer. The governing equations for the clear fluid flow are coupled with the ones for the seepage in the porous layer, for which the generalized Darcy’s law is employed. A linear stability analysis of both...

The paper investigates the applicability of Kinematic and Diffusive Wave models for mud-flows with a power-law shear-thinning rheology. In analogy with a well-known approach for turbulent clear-water flows, the study compares the steady flow depth profiles predicted by approximated models with those of the Full Dynamic Wave one. For all the models...

Dikes and levees are encountered very often along rivers. They are crucial as defence structures for flow channelization, protecting population and properties from floods as well as against lateral riverbed migration. However, the combination of their aging and increased exposition to extreme hydrological events may cause these structures to breach...

The identification of the source of a contamination in a river, either accidental or intentional, is of extreme interest for both the technical and scientific communities. To this aim, the recent development of innovative wireless sensors, coupled with computational tools capable of analyzing big data almost in real-time, offers novel opportunities...

The paper explores the possibility of predicting the occurrence of antidunes in gradually-varied flows through non-equilibrium morphological models natively derived, under the long-wave approximation, for fast geomorphic transients. Starting from a recent two-phase gradually-varied flow model, an improved version, which partially accounts for the b...

A depth-averaged model with a power-law rheology, usually adopted for debris flow of fine sediment-water mixtures, is studied analytically, considering the complete (Full Dynamic Model) and the simplified momentum equations, known as Kinematic, Diffusion, and Quasi-steady Models. Applying the Laplace transform to the linearized equations, the analy...

In mountainous areas after long or intense rains, landslides may evolve into debris- or mud-flows. Their impact against obstacles may produce huge damages, sometimes with loss of lives. Prediction of the impact forces is required for a proper design of the flow barriers protecting risk prone areas. To this aim, both the effective characterization o...

The impact of a dam-break wave on an erodible embankment with a steep slope is studied in the paper using both experimental and numerical approaches. The laboratory experiments have been specifically designed and performed for a range of the storage water levels and the embankment elevations and slopes. The simulations were carried out using a rece...

The paper investigates the influence of the inlet boundary condition on the spatial evolution of natural rollwaves in a power-law fluid flowing in steep slope channels. The analysis is carried out numerically, by solving the von Kármán depth-integrated mass and momentum conservation equations, in the long-wave approximation. A second-order accurate...

The identification of the source of a contamination in a river, either accidental or intentional, is of extreme interest for the technical and scientific communities, because it is the preliminary step towards risk mitigation for human, animal and vegetable health. Recently, the development of innovative wireless sensors, coupled with computational...

This paper investigates the spatial evolution of a disturbance in an open-channel flow of a power-law fluid at non-uniform accelerated and decelerated initial profiles, up to the occurrence of roll-waves in mild and steep slope channels. Both theoretical and numerical analyses are applied to the depth-averaged continuity and momentum conservation e...

The present work investigates the effect of the flow profile induced by an inlet condition on the roll-wave evolution in turbulent clear-water flows. The study employs theoretical and numerical analyses. Firstly, the influence of the inlet condition on the spatial evolution of a single perturbation in a hypercritical flow is examined through the ex...

Fast geomorphic transients may involve complex scenarios of sediment transport, occurring near the bottom as bed load (i.e., saltating, sliding, and rolling) or as suspended load in the upper portion of the flow. The two sediment transport modalities may even coexist or alternate each other during the same event, especially when the shear stress va...

Simplified wave models -such as kinematic, diffusion and quasi-steady -are widely employed as a convenient replacement of the full dynamic one in the analysis of unsteady open-channel flows, and especially for flood routing. While their use may guarantee a significant reduction of the computational effort, it is mandatory to define the conditions i...

In the present paper the stability of gradually varying mud-flows in wide open channel is analyzed. The governing equations derive from a Saint–Venant-like approach with a Herschel & Bulkley model for the fluid rheology. In order to define the stability of a given initial accelerating or decelerating flow depth profile, the spatial evolution of a w...

Bank failure is an important phenomenon in geomorphic processes. In the presence of riverbanks or steep bedforms, collapse mechanisms induced by the water-level rise deeply affect the bed evolution along with the sediment-transport processes. In this paper an algorithm capable of simulating such mechanisms in a two-dimensional two-phase morphodynam...

In the present paper the mathematical character of the two-phase depth-averaged morphodynamical model proposed by Di Cristo et. al (2014) is discussed. In particular, in this model the bed-load concentration is dynamically evaluated provided that an algebraic expression for bed-load thickness is assumed. To this aim, some adaptations of empirical c...

2) Novaetech Srl-INAF spin-off company, Italy (3) Promete Srl-CNR spin-off company, Italy (4) Abstract The presence of some organic and inorganic contaminants in surface water is a longstanding problem in many countries. Contaminants may reach surface waters, accidentally or intentionally; via agricultural activities or from sewage discharges and t...

The ‘Floods Directive’ 2007/60/CE by the European Parliament requires the characterization of flood hazard by multi-scenario hydraulic analyses, based on the estimation of flow velocity and water depth or free-surface level over flooded areas. In principle, this evaluation demands a complete analysis of the watershed hydraulics, based on two- or ev...

The adoption of the Diffusive Wave (DW) instead of the Full Dynamic (FD) model in the analysis of mud flood routing within the shallow-water framework may provide a significant reduction of the computational effort, and the knowledge of the conditions in which this approximation may be employed is therefore important. In this paper, the applicabili...

The study of unsteady shallow-layer flows, as those occurring during floods, may be performed through either fully dynamic models or using simplified momentum equations (e.g. kinematic, diffusion and quasi-steady approximations). Among the latter, kinematic approximation may provide a significant reduction of the computational effort, which represe...

The sustainable management of water supply networks requires the control of physical pipe leakages, as those due to junction obsolescence or pipe creeping. These leakages usually increase with the operating pressure, and their discharge is commonly assumed to scale with a power of the pressure. The same functional form is also employed to evaluate...

Unsteady shallow-layer flows may be described through full dynamic models or using simplified momentum equations, based on kinematic, diffusion, and quasi-steady approximations, which guarantee a reduction of the computational effort. This paper aims to investigate through linear analysis the applicability range of simplified shallow-wave models wi...

The paper addresses the prediction of roll-waves occurrence in mud-flows. The spatial growth of a point-wise disturbance is analytically described, based on the linearized flow model of a Herschel and Bulkley fluid, in the neighborhood of an initial uniform base condition. The theoretical achievements allow to generalize to mud-flows the minimum ch...

Proceedings of 2013 IAHR World Congress ABSTRACT : Fast geomorphic transients may involve complex scenarios of sediment transport, occurring as bed - load (i.e. saltating, sliding and rolling) in the region close t o the bottom, or as suspended load in the upper region of the flow . These two modalities of sediment transport may even coexist or alt...

In the paper an algorithm for river bank failure integrated in a two - phase morphodynamic framework is presented. A triangular non - staggered mesh is adopted for the numerical integration of the model. The proposed approach allows for the univocal definition of the slope in each cell. The geof ailure operator guarantees that when in the cell the...

On October 23, 2007, the European Parliament approved the ‘Floods Directive’ 2007/60/CE (FD), aimed to regulate the procedures for hydraulic risk assessment. One of its most innovative aspects consists in the characterization of flood hazard by multi-scenario hydraulic analyses, based on the estimation of flow velocities and water depths all over t...

The occurrence of roll-waves in mud-flows is commonly investi-gated starting from the formulation of the marginal stability threshold of a linearized one-dimensional viscoplastic (shear-thinning) flow model. Since for this non-newtonian rheological model such a threshold may oc-cur in hypocritical flow, the downstream boundary condition may have a...

The flow of a thin layer of power-law fluid on a porous inclined plane is considered. The unsteady equations of motion are depth-integrated according to the von Karman momentum integral method. The variation of the velocity distribution with the depth is accounted for, and it is furthermore assumed that the flow through the porous medium is governe...

The study of formation and evolution of waves in mud-flows is strongly motivated by their destructive power. The rheology of these flows, which involve massive solid transport, is often described using linear or non-linear viscoplastic models. The paper analyzes the wave dynamics of mud-flows, presenting the linearized response of the 1D uniform fl...

The paper introduces a 2D shallow water model based on a two-phase formulation for the analysis of fast geomorphic transients occurring in the context of river morphodynamics. Mass and momentum conservation principles are separately imposed for both phases. The model naturally accounts for non-equilibrium solid transport, since neither instantaneou...

In the present paper, an analytical expression of the Green’s function of linearized Saint-Venant equations (LSVEs) for shallow water waves is provided and applied to analyse the propagation of a perturbation superposed to a uniform flow. Independently of the kinematic character of the base flow, i.e., subcritical or supercritical uniform flow, the...

Sediment transport may occur during fast geomorphic transients as a consequence of strong upward momentum fluxes due to turbulence and/or of intense erosion of a loose bed. Under these circumstances, sediments will move with the distinctive features of bed-load in the region close to the bottom,whereas suspended sediment will follow the carrying fl...

The present work investigates the response of a porous media to an unsteady forcing resulting from the superposition of an harmonic component to a mean one. The analysis is carried out both in terms of global parameters and local fields obtained processing data from numerical solution of the Navier-Stokes equations at pore level performed with a sp...

The initial phase of roll-wave development is investigated by means of spatial linear stability analysis using the St. Venant equations, subject to a pointwise time-varying oscillating disturbance. The predicted spatial growth is compared with both Vedernikov's results and those computed with a fully non-linear model. It is shown that for large val...

In the paper a linear stability analysis of a one–dimensional morphodynamical model is presented. The local equilibrium assumption on the solid discharge is removed and a dynamical description of the bed–load transport is employed. Both unsteady and quasi–steady flow models are analysed and discussed. The results reveal the existence, at moderate F...

The paper investigates the influence of the resistance coefficient variability onto the spatial development of roll-waves. Two models, based on time-asymptotic solutions of the linearized St. Venant equations, subject to either impulsive or oscillating perturbation, have been modified by including the dependence of the resistance coefficient on flo...

This paper analyses conditions for roll-waves formation in homogeneous granular flows with the aim of predicting their occurrence in finite length channels. With reference to a wide class of constitutive equations of the flowing medium, the response of the linearized one-dimensional flow model to a pointwise instantaneous disturbance is studied and...