A new cost effective, long life and low resistance filter cartridge for water treatment

Abstract Filtration processes constitute the major solution among water treatments, which appear always necessary nowadays to make water suitable for human consumption or domestic uses, due to the gradual deterioration of its quality as a consequence of environmental pollution and industrial processes. In this paper a new type of filtering cartridge is presented, aimed at overcoming the main inconveniences shown by usual commercial cartridges. These drawbacks have been highlighted in a previous experimental work conducted in the Laboratory of Environmental and Maritime Hydraulics (LIDAM) of University of Salerno and aimed at evaluating the head losses produced by the most common filtration cartridges, especially under progressive clog conditions. Head losses, in fact, are particularly undesirable for low-pressure plants, where they can inhibit the normal operation of the installed apparatus. The analysis of the experimental results permitted to reveal several features of the filtration process in commercial cartridges and draw up different remarks, which led, after further laboratory tests here presented, to the design of a new economic, non-toxic, low-resistance and long life-cycle filtration cartridge, proposed and described in this paper. This cartridge, is basically made of a central element in inert cotton wrapped in a cylindrical polypropylene support, similar to the commercial one but with the core protected by elements, such as white marble pebbles, effective microorganism ceramic cylinders and granular active coal, which, while ensuring a good hydraulic permeability, is capable of stopping much of the particles suspended in the fluid before they reach the cartridge causing its clogging. The new design permits, therefore, to significantly reduce, compared with the commercial cartridges, average head losses even for high clogging degrees, and to increase, as a consequence, the life cycle of the cartridges

Simulating Flows with SPH: Recent Developments and Applications

The chapter discusses recent theoretical developments and practical applications of the Smoothed Particle Hydrodynamics (SPH) method with specific concern to liquids. SPH is a meshless Lagrangian technique for the approximate integration of spatial derivatives, using particle interpolation over a compact support, without the usage of a structured grid. Its main related advantage is the capability of simulating the computational domain with large deformations and high discontinuities, bearing no numerical diffusion because advection terms are directly evaluated. SPH has recently become very popular for the simulation of fluid motion using computers, covering different fields, e.g. free surface flows, multiphase flows, turbulence modelling. In the following, recent theoretical achievements of SPH are firstly presented, concerning (1) numerical schemes for approximating governing equations, such as the Navier Stokes ones, most widely adopted in fluid dynamics, (2) smoothing or kernel function properties needed to perform the function approximation to the Nth order, (3) restoring consistency of kernel and particle approximation, yielding the SPH approximation accuracy. Secondly computation aspects related to the neighbourhood definition are discussed. Field variables, such as particle velocity or density, are evaluated by smoothing interpolation of the corresponding values over the nearest neighbour particles located inside a cut-off radius “rc”. The generation of a neighbour list at each time step takes a considerable portion of CPU time. Straightforward determination of which particles are inside the interaction range requires the computation of all pair-wise distances, a procedure whose computational time would be of the order O(N2), and therefore unpractical for large domains. Finally, some practical applications are presented, primariliy concerning free surface flows. The capability to easily handle large deformation is shown

Large-scale wave breaking over a barred beach : SPH numerical simulation and comparison with experiments

Acknowledgements The experiments were supported by the European Community’s Horizon 2020 Programme through the grant to the budget of the integrated infrastructure initiative HYDRALAB＋, Contract no. 654110, and were conducted as part of the transnational access project HYBRID. Dr. Corrado Altomare acknowledges funding from the Spanish government and the European Social Found (ESF) under the programme ’Ramón y Cajal 2020’ (RYC2020-030197- /AEI/10.13039/501100011033). Pietro Scandura acknowledges the support received from the University of Catania, Italy by funding the research project ‘Valutazione del rischio idraulico in sistemi complessi (VARIO)’.Peer reviewedPublisher PD

Regular wave seakeeping analysis of a planing hull by smoothed particle hydrodynamics: a comprehensive validation

In this work, the dynamics of a planing hull in regular head waves was investigated using the Smoothed Particle Hydrodynamics (SPH) meshfree method. The simulation of the interaction of such vessels with wave trains features several challenging characteristics, from the complex physical interaction, due to large dynamic responses, to the likewise heavy numerical workload. A novel numerical wave flume implemented within the SPH-based code DualSPHysics fulfills both demands, guaranteeing comparable accuracy with an established proprietary Computational Fluid Dynamics (CFD) solver without sharpening the computational load. The numerical wave flume uses ad hoc open-boundary conditions to reproduce the flow characteristics encountered by the hull during its motion, combining the current and waves while adjusting their properties with respect to the vessel’s experimental towing speed. It follows a relatively small three-dimensional domain, where the potentiality of the SPH method in modeling free-surface flows interacting with moving structures is unleashed. The results in different wave conditions show the feasibility of this novel approach, considering the overall good agreement with the experiments; hence, an interesting alternative procedure to simulate the seakeeping test in several marine conditions with bearable effort and satisfying accuracy is established.Ministerio de Ciencia e Innovación | Ref. PID2020-113245RBI00Xunta de Galicia | Ref. ED431C 2021/44Ministerio de Ciencia e Innovación | Ref. TED2021-129479AI00Xunta de Galicia | Ref. ED481A-2021/337Ministerio de Ciencia e Innovación | Ref. RYC2020-030197-

Free-Surface Flow Simulations with Smoothed Particle Hydrodynamics Method using High-Performance Computing

Today, the use of modern high-performance computing (HPC) systems, such as clusters equipped with graphics processing units (GPUs), allows solving problems with resolutions unthinkable only a decade ago. The demand for high computational power is certainly an issue when simulating free-surface flows. However, taking the advantage of GPU’s parallel computing techniques, simulations involving up to 109 particles can be achieved. In this framework, this chapter shows some numerical results of typical coastal engineering problems obtained by means of the GPU-based computing servers maintained at the Environmental Physics Laboratory (EPhysLab) from Vigo University in Ourense (Spain) and the Tier-1 Galileo cluster of the Italian computing centre CINECA. The DualSPHysics free package based on smoothed particle hydrodynamics (SPH) technique was used for the purpose. SPH is a meshless particle method based on Lagrangian formulation by which the fluid domain is discretized as a collection of computing fluid particles. Speedup and efficiency of calculations are studied in terms of the initial interparticle distance and by coupling DualSPHysics with a NLSW wave propagation model. Water free-surface elevation, orbital velocities and wave forces are compared with results from experimental campaigns and theoretical solutions

A DEM approach for simulating flexible beam elements with the Project Chrono core module in DualSPHysics

This work presents a novel approach for simulating elastic beam elements in DualSPHysics leveraging functions made available by the coupling with the Project Chrono library. Such numerical frameworks, belonging to the Meshfree Particle Methods family, stand out for several features, like complex multiphase phenomena, moving boundaries, and high deformations which are handled with relative ease and reasonable numerical stability and reliability. Based on a co-rotating rigid element structure and lumped elasticity, a cogent mathematical formulation, relying on the Euler–Bernoulli beam theory for the structural discretization, is presented and applied to simulating two-dimensional flexible beams with the discrete elements method (DEM) formulation. Three test cases are presented to validate the smoothed particle hydrodynamics-based (SPH) structure model in both accuracy and stability, starting from an equilibrium test, to the dynamic response, and closing with a fluid–structure interaction simulation. This work proves that the developed theory can be used within a Lagrangian framework, using the features provided by a DEM solver, overtaking the initial limitations, and hence applying the results of static theories to complex dynamic problems.Xunta de Galicia | Ref. ED431C 2021/44Xunta de Galicia | Ref. ED481A-2021/337Ministerio de Ciencia, Innovación y Universidades | Ref. IJCI-2017-32592Agencia Estatal de Investigación | Ref. PID2020-113245RB-I0

Efficiency and survivability analysis of a point-absorber wave energy converter using DualSPHysics

Smoothed Particle Hydrodynamics (SPH) method is used here to simulate a heaving point-absorber with a Power Take-Off system (PTO). The SPH-based code DualSPHysics is first validated with experimental data of regular waves interacting with the point-absorber. Comparison between the numerical and experimental heave displacement and velocity of the device show a good agreement for a given regular wave condition and different configurations of the PTO system. The validated numerical tool is then employed to investigate the efficiency of the proposed system. The efficiency, which is defined here as the ratio between the power absorbed by the point-absorber and its theoretical maximum, is obtained for different wave conditions and several arrangements of the PTO. Finally, the effects of highly energetic sea states on the buoy are examined through alternative configurations of the initial system. A survivability study is performed by computing the horizontal and vertical forces exerted by focused waves on the wave energy converter (WEC). The yield criterion is used to determine that submerging the heaving buoy at a certain depth is the most effective strategy to reduce the loads acting on the WEC and its structure, while keeping the WEC floating at still water level is the worst-case scenario.Agencia Estatal de Investigación | Ref. ENE2016-75074-C2-1-RAgencia Estatal de Investigación | Ref. IJCI-2017-32592Xunta de Galicia | Ref. ED431C 2017/6

A numerical investigation of flow dynamics over a trapezoidal smooth open channel

The paper presents a numerical investigation of the flow dynamics in a laboratory flume. The adopted geometry consists of a U shaped trapezoidal smooth open channel with a fixed slope and unerodible bed. The branches, 3m of length each, are linked with a joint 1m long, realizing two 90 degrees bends. The system is fed upstream with a water discharge under critical conditions while a Cipolletti weir is set downstream to control flow profiles. Steady flow characteristics are deduced by means of three different softwares: a pure Lagrangian developed by the author, based on the Weakly Compressible Smoothed Particle hydrodynamics (WCSPH) technique, Flow3D® and HEC-RAS®. Depending on the specific boundary conditions being given, velocity profiles and water interfaces at certain cross sections are deducted by using the first two codes. Results are discussed then spatially averaged in terms of mean velocities and water depths respectively to make a comparison with the ones obtained with HEC-RAS, showing a satisfactory agreement

Water supply network rehabilitation: A case study

Serino, Southern Italy, known by the locals as “il paese dell’acqua” which translated reads as ”the town of waters”, suffers recurrent water shortages due to the obsolescence of the local water supply network. Such a circumstance sets up a paradox since the “Serino aqueduct” alone supplies Naples, the capital of Campania Region and its neighbourhood, with a discharge of approximately 1–3.5 m3/s (Fiorillo et al., 2007). Belonging to the well known Terminio karst aquifer, moderately conditioned by groundwater abstraction (Pagnozzi et al., 2017), Serino springs have being exploited since long time. Consider that the Serino aqueduct, also known as Aqua Augusta, was built during the Augustus period, almost certainly at the end of the 1st century B.C., when Marco Agrippa was the curator aquarum of the Roman Empire (De Feo and Napoli, 2007). Karst aquifers represent a fundamental resource as they supply drinkable water to about a quarter of the world’s population including European cities such as London, Paris, Rome and Vienna (Ford and Williams, 2007). The rehabilitation of water supply networks is a crucial aspect of sustainable urban development in a scenario where strategies for limiting the effects of climate change have to be taken into account to preserve water quality. Unfortunately, most water utilities do not developed a long-term decision making approach to prevent the aging of pipes and degradation of hydraulic manufacts. It is common to take decisions on a year-to-year base which elements of the water supply system should be rehabilitated or, even worse, on impeding emergency calls. Numerous rehabilitation strategies have been presented in the literature, e.g. Engelhardt et al., 2000; Scholten et al., 2014; Shin et al., 2016, as well as related applications (Aşchilean and Giurca, 2018; Viccione et al., 2018). The purpose of the paper is to discuss the rehabilitation of a water supply network with reference to a case study