Ioan David

Polytechnic University of Timisoara · Department of Hydrotechnics (HYDRO)

The modelling of the three-dimensional flow generated by a partially penetrated well/borehole into the aquifer requires the correct mathematical representation of the interdependence between the piezometric head and the water inflow/outflow along the borehole, considering the fact that this dependence, from a mathematical point of view, has singula...

The sector affected by surplus or scarcity of water requires proper understanding of river and landscape system behavior, what is possible to be done to prevent potential damages and losses need skilled professionals, who are familiar also with the newest IT based hydroinformatic tools and technological achievements to find the best possible soluti...

Light Nonaqueous Phase Liquids (LNAPL) are mineral oil products which, due to accidents can lead again and again during storage, transport, and processing to strong contamination of groundwater. Consequently, it is of interest to investigate the spreading transport behavior of these substances in the subsurface. The main objective of this paper is...

Water Framework Directive and Flood Directive of European Commission establishes the need for preparation of flood risk maps for each member country on each important hydrographic basins. Based on these established the flood risk management plan (must be finalized by end of 2015), which is a communicator and disseminator tool of the knowledge gaine...

In the era of the increasing implementation of renewable energy sources in the electrical energy supply the demand for energy storage continues to grow. This is because the renewable energy sources, mainly in the form of wind and solar energy, are sustainable, but at the same time are subject to natural fluctuations. The wind does not always blow,...

In the era of the increasing implementation of renewable energy sources in the electrical energy supply the demand for energy storage continues to grow. This is because the renewable energy sources, mainly in the form of wind and solar energy, are sustainable, but at the same time are subject to natural fluctuations. The wind does not always blow,...

It is known that hydropower is one of the most reliable and proven sources of generating electricity, with three important attributes: it is renewable, available on demand, and it can be used to store power. But the normal life expectancy of a hydroelectric power plant is only 30 to 35 years and consequently renovation and usually upgrading is requ...

Groundwater flow in shallow aquifer (i.e. groundwater reservoir with large plane extension in relation to the depth) containing lake, pond, groundwater recharge or drainage pit, foundation pit etc., referred further as groundwater extraction/recharge cavity or cavern represent a very important practice-oriented topics. In this regard in a former pa...

REPLACEMENT POSSIBILITIES OF THE HEAVY OVERLOAD PISTON OF GRAVITY- HYDRO-POWER-TOWER ENERGY STORAGE PLANTS USING COMPRESSED AIR Prof. Emeritus DSc. Eng. Ioan David*1 PhD Student Eng. Ioan VLAD 1 Lecturer DSc. Eng. Camelia Stefanescu1 1 Polyethnic University Timișoara, Department of Hydrotechnical Engineering, Romania ABSTRACT In the era of the...

ABSTRACT Due to the flow behavior complexity, the calculation of local head losses needs to be based on experimental results. Although there is great literature regarding the study of valves, and a part of it contains detailed results of local head loss too, these values are always related to a specific manufacturer. This means that for accurate de...

ABSTRACT Energy efficiency is a key factor of today’s engineering practice. Water and wastewater systems (made up of supply and disposal networks, treatment plants etc.) often contain under pressure sections. Their energy efficiency strongly depends on the accuracy of the head loss evaluation including local head loss. In these systems a great amou...

ABSTRACT. Groundwater wellbore systems are used in engineering mainly, as groundwater supply plants for drinking water like fully or partially penetrating wells, well with laterals, as subsurface drainage reclamation, as coupled subsurface injection/recovery wells in petroleum or in geothermal exploitation and so on. The characteristic geometrical...

Das vorliegende Buch richtet sich in erster Linie an Studierende der deutschsprachigen Abteilung des Bauingenieurwesens an der POLITEHNICA Universität Timişoara, aber auch an Studierende anderer Hochschulen oder vergleichbaren Bildungseinrichtungen. Hauptziel des Buches ist es die Vermittlung der im Studium erforderlichen hydraulischen Grundkenntni...

MATHEMATICAL MODEL FOR CALCULATION OF SOIL LOSS ON WATERSHED SLOPES Erika Beilicci, Ioan David, Robert Beilicci, Mircea Visescu Department of Hydrotechnical Engineering, Faculty of Civil Engineering, “Politehnica” University of Timisoara, 1/A George Enescu Street, 300022 Timisoara, Romania Abstract Soil erosion by water, sediment transport, sedime...

The increased frequency of disaster events and the need for a rapid response for the prevention and remediation of flood disasters require realization of flood risk maps with very good precision based on high performance hydrodynamic river models using advanced hydroinformatics tools. Modelling performance, topographical data quality and quantity,...

At the neighbourhood of several drainage objects types in shallow aquifer like fully penetrated wells, partially penetrated wells, well with laterals, horizontal drainages etc. groundwater flow forms contain frequently 2D/3D singular behaviours (e.g. logarithmical or polar singularities), which require special attention by coarse grid simulations G...

Regional Groundwater simulation models required usually grid blocks with much larger dimensions than the characteristic transversal dimension of Drainage Objects (DO) like wellbores or drainage trenches (e.g. diameter, penetration depth etc.). In the same time the length dimension of a DO is sufficiently large in order to occupy several grid blocks...

The first part of the chapter presents general and specific issues concerning the use of hydroinformatic tools in hydraulic modeling as important step in decision-making activities in extreme situations such as floods. The special importance of these issues is the fact that currently cannot conceive a project related to water management without the...

Geothermal energy source is the heat from the Earth which ranges from the shallow ground (the upper 100m of the Earth) exploitable using geothermal ground-source heat pumps, to the deep hot water and hot rock resources located in a few thousand meters beneath the Earth's surface and are exploitable for electric power generation or direct-use for he...

ABSTRACT Due to the frequency and damages produced by floods in recent decades in various river basins in Europe, European Union countries have developed and implemented Directive 2000/60/EC - the Framework for Community Action in the Field of Water Policy and Directive 2007/60/CE - on the Assessment and Management of Flood Risks. These directives...

The first part of the chapter presents general and specific issues concerning the use of hydroinformatic tools in hydraulic modeling as important step in decision-making activities in extreme situations such as floods. The special importance of these issues is the fact that currently cannot conceive a project related to water management without the...

The main objective of the paper is to present a relatively simple modelling method for estimate the influence of hydraulic head losses of the internal non linear flow along a horizontal drainage tube (or along of an vertical partially penetrating well) on the groundwater inflow distribution along the drainage tube. As coupling condition the flux co...

The modelling of open channel flows as 1D scheme is usually performed by advanced numerical models developed in the last years, in which an essential problem is the approach of the shear stress at the channel bed. Starting from fundamental equations of the hydrodynamics, in the paper, the basic equation for 1D open channel flow will be obtained and...

Water Framework Directive and Flood Directive of European Commission establishes the need for preparation of flood risk maps for each member country on each important hydrographic basins. Based on these established the flood risk management plan (must be finalized by end of 2015), which is a communicator and disseminator tool of the knowledge gaine...

Abstract. It is known that sewerage construction management for storm water represents a major problem which is augmented through urban development into the last years. Urban development leads to reducing the infiltration rate of the rainwater and thus to increased discharge peak. Both aspects have an undesirable impact on the storm water managemen...

Abstract: In actually context of the general need to increase the share of alternative energy sources, the near surface geothermal energy i.e. the natural energy reservoir of the earth (up to 200-300m) which can be exploited to heating or cooling using ground source heat pump (GSHP) systems, have an important place. The performance of such an syste...

For modelling of the pollutants transport process in aquifer a very important aspect has the analysis of aquifer pollution with heavy metals. The surface complexation process of heavy metals on the grains of porous-media is reversible similar to the adsorption-desorption in transport processes, in aquifer pollution, but strongly dependent of pH val...

The most common numerical methods to simulate pollution transport in aquifers are the finite difference method (FDM) and the random walk method (RWM). In both methods, discretisation of the flow domain is used which, as it is known, can significantly influence the results of simulation, i.e. the spatial distribution of the pollutant concentration a...

In this paper is briefly presented the essential features of water monitoring in its applications for groundwater management. The paper answers to questions like: What type of process should be surveyed? Where should the data collecting sensors be placed? How should the information from sensors be used? Reliability and usability issues are presente...

The focus of this work was the influence of two geo plastic reinforcement in dikes in terms of the flow behavior and thus examined the stability and possible erosion. Based on a parametric study, different models of dike, with representative reinforcement with geo-plastic materials were analyzed taking into account different groups of soil paramete...

Big quantities of fly ash and slag (industrial waste materials) are stored in enormous dumps causing serious environmental concerns like: heavy metals contamination of lands and water, occupy of vastest lands (ha), fly ash dispersing by wind blowing (with great discomfort for people) …. On the other hand, these deposits of fly ash are made in a big...

Geothermal energy source is the heat from the Earth, which ranges from the shallow ground (the upper 100 m of the Earth) to the hot water and hot rock which is a few thousand meters beneath the Earth's surface. In both cases the so-called open systems for geothermal energy resource exploitation consist of a groundwater production well to supply hea...

Geothermal energy source is the heat from the Earth, which ranges from the shallow ground (the upper 100 m of the Earth) to the hot water and hot rock which is a few thousand meters beneath the Earth’s surface. In both cases the so-called open systems for geothermal energy resource exploitation consist of a groundwater production well to supply hea...

Spiral chambers and aspiration elbows with oval section for pumps can be manufactured by casting and of welded shells. In the latter case result lighter assemblies and are obtained better yields due to lower roughness. Each shell represents a developable ...

The paper presents Lü system from the mechanical geometry point of view. We analyze a specific case for which Lü system has a Hamilton-Poisson realization and we point out some of its geometrical and dynamical properties.

Mathematical formulation of processes in different areas of physics, e. g. fluid flows and transport phenomena through porous media, electrostatics and electrodynamics, heat conduction etc. lead to boundary value problems for partially differential equation elliptical type in term of a potential function which is characteristic for the considered p...

In this phase of the report a briefly presentation and analysis of the governing equations and methods for modelling and solving flow and heat transfer processes and the corresponding initial and boundary value problems in geothermal reservoirs (porous media consisting of rock-matrix whose pores are filled with water) which are currently used for c...

The paper aims to explore the possibility of developing a Pumped Storage Hydropower Plant (PSHPP) within an existing complex hydro system on upper Barzava, by employing the given hydro potential of the accomplished water development. The present study analyses the hydropower parameters of a proposed Gozna-Semenic PSHPP, the power station looking to...

Abstract: A short overview of some own results relating the modelling of flow- and transport processes in porous media obtained in the last decades is discussed. There will be referred to the following themes: general aspects of the mathematical modelling and the reliability of the basic equations of the groundwater flow with results embodied in se...

In the paper the realization of an Hydraulically test and exhibition stand in the modeling hall of the Faculty of Hydrotechnics in Timisoara is presented which is an exhibition stand with HAWLE fittings, combined with the test region for students and researchers. The idea of such a stand was initiated in 2008, during a cooperation visit by Professo...

At present, database management is a key role in monitoring, maintenance and exploitation of hidroedilitar resources. The paper has as starting point the request of a research contract between Hydrotechnical Faculty of Timisoara and the City Hall of Timisoara. The paper target is to illustrate the possibility of achieving a proper inventory of wate...

It is known that large hydrocarbon spills around refineries, storage tanks, leaking pipelines or other sources pollute the groundwater forming of large pancake-like lens on the groundwater table as free phase which has density less than that of water and is called as Light Non Aqueous Phase Liquid (LNAPL). The comprehensive analysis of such LNAPL l...

The purpose of this publication is to provide the reader with a general understanding of how agricultural drainage waters can be managed to help balance production and environmental goal. The management of Bihor’s county agricultural management drainage waters has important consequences for agricultural productivity and profitability, and for envir...

SCIENTIFIC BULLETIN OF “Politehnica” University of Timişoara, Romania Transactions on HYDROTEHNICS Vol. 52 (66), 2007, No.1, ISSN 1224-6042 Seewald, G., Gutzke, T., Diaz, J., David, I.:- Spatial Assessment of Groundwater Information in large-scaled catchments-Areas Abstract The management of groundwater resources for the supply of German cities,...

Numerical methods used in the groundwater flow medelling recorded a large increasing within last decades because of continuously development of the methods, pre-and post-processing techniques and not least because of the evolving skills of users. Near the singularities encountered in the numerical modeling techniques different results are obtained...

Conventionally, the ground water containing high iron and manganese concentration is treated in surface plants with physical chemical and biological processes. An alternative way is the in situ treatment when water enriched with oxygen is injected cyclic into the underground where an oxidation reactor appear and the iron(II) is oxidized. The paper...

The estimation of area-specific hydro-geological parameters or coefficients (HGPCs) for groundwater modelling through conventional methods such as Pump Tests may not be suitable for contaminated sites, as these infiltration/extraction Tests may lead to inestimable additional risks of contaminant spread to protected zones and settlements. For early...

Ground water data collection is carried out under precise supervision and control in a catchment area. The storage, evaluation and utilization of groundwater information are of utmost importance to ensuring both the protection of the quality of water for industrial use and its use as potable water. The contamination of groundwater sources through s...

Groundwater contamination with immiscible fluids known as non-aqueous phase liquids (NAPL) can lead to the formation of a separate phase in groundwater. The mobile part of NAPL may accumulate in the saturated zone as a continuous free-phase lens above the groundwater table (Light NAPL) or on the bottom of the impermeable ground layer (Dense NAPL)....

The modeling of the spreading of contaminant non-aqueous phase liquid (NAPL) as free-phase in groundwater has been gaining interest in the last decade due to the increasing importance for the accurate prognosis of the expansion of the contaminated area in aquifer. Under certain conditions and assumptions the governing equation of free-phase NAPL-fl...

This paper presents a methodology for the technical and economical design of agricultural horizontal drainage network. A drainage study uses data obtained from, among others, topographical, hydrological, hydro geological and soil studies as well as experimental laboratory research. The soil samples taken from the field are analyzed to establish the...

The main goal of this paper is to provide an approach to model the recovery of free-phase (mobile) NAPL. Based on the simplified assumptions of a so-called \“sharp interface model” and vertical equilibrium between the two immiscible mobile phases (i.e. NAPL/Water), a simplified mathematical method to model the generated coupled flow of the two immi...

This paper presents a computational method and formulas to describe the recovery of “pancake” oil pollution lying on the immobile groundwater table using partially penetrating wells or horizontal drainpipes. Based on the introduction of potential function for a light phase flow, the proposed mathematical model leads to partial differential equation...

Was man im Studium über Grundwasser wissen muss Grundwasserhydraulik ist eine Einführung in die Grundlagen der mathematisch-numerischen Modellierung von Strömungs- und Transportvorgängen im Grundwasser. Sowohl für Studenten als auch für Praktiker wird das Fachgebiet durch wachsende Nutzung und Beeinflussung der Grundwasserreservoire zu einem immer...

In the past, the development of mathematical models for ground water flow was mainly concentrated on large-scale models, calculated by means of the Finite Element Method (FEM) (1 "-order region). However, this method is not appropriate for simulating the hydraulic properties of flow in a region near a groundwater supply and recharge system (GWS/RS)...

Die in Kap. 3 aufgezeigten Problemstellungen sind mit Hilfe verschiedener Verfahren lösbar. In einfachen Fällen führen analytische Methoden zu geschlossenen Lösungsfunktionen. Im allgemeinen ist es immer möglich, numerische Verfahren anzuwenden. In diesem Kapitel werden analytische und numerische Verfahren vorgestellt und mit Hilfe von Beispielen b...

Die Aufgabenstellungen der Grundwasserhydraulik werden hauptsächlich mit Grundgleichungen beschrieben, die ihren Ursprung in den Postulaten der Hydromechanik, Massenerhaltung und lineare Impulsbilanz, haben. Die daraus hergeleiteten Strömungsgleichungen Bewegungsgleichung (Fließgleichung) u. Bilanzgleichung (Kontinuitätsgleichung) sind die Grundgle...

Für den Aufbau eines systembeschreibenden Modells ist die Betrachtung der Grundgleichungen der Grundwasserströmung nicht ausreichend.

Für die mathematische Darstellung der Hydromechanik wird der EUKLIDISCHE RAUM (R3 ) (dreidimensionaler Vektorraum) mit dem kartesischen Koordinatensystem verwendet.

Die zunehmende industrielle und landwirtschaftliche Aktivität in den letzten Jahrhunderten ist mit dem Umschlag einer großen Anzahl von grundwassergefährdenden Schadstoffen in großen Mengen verbunden. Diese stellen zusammen mit den über Jahrzehnte entstandenen Altablagerungen für das Grundwasser ein großes Verschmutzungspotential dar.

Contamination of groundwater resources by hazardous substance has become an issue of increasing interest. The first step to reduce an uncontrolled contamination due to migration is the recovery of this substance by means of extraction wells placed in the aeration zone above the saturated groundwater. The paper presents analytical solutions for a si...

A comparison between classical and numerical methods applied on the case study of the Iron Gate I hydropower plant, Rumania is presented. The technical solution obtained is described. The differences between the applications of classical formulae and numerical methods are discussed. -from Authors

This paper presents the construction and operation of a laboratory ultrasonic field filtering device, having a metal filtering membrane oscillating in the filtrate flow direction. The solid-liquid suspension separation intensification by filtration in an ultrasonic field with this device is justified by the following phenomena accompanying the acou...

A mathematical model is presented for a hydraulic system consisting of a linear structure for artificial groundwater recharge (gallery or cutting) and a number of wells, taking into account the local-three-dimensional character of the flow, determined by the finite length and the partial penetration of the cutting or the circular cross-section of t...

The authors propose a simple explicit scheme with equal increments along the abscissa and ordinate. The solution scheme is relatively simple, where the effect of the linear change in the diffusion coefficient is represented by a correction term. The authors solve for diffusion approximately in the nonstationary state, where the diffusion coefficien...

ÜBER EIN BERECHNUNGSVERFAHREN DER VERLUSTHÖHE BEIM EINTRITTSWIDERSTAND DES WASSERS IN DIE DRAINROHRE l. DAVID In der darliegenden Arbeit werden die hydraulischen örtlichen Erscheinungen untersucht, die im Bereich der Drainrohre unter den Bedigungen der Geometrie der EintrittsÖffnungen am Rohr und des Einflusses von Zonen geänderter Durchlossigkeit...

A study was made of the local hydraulic phenomena occurring in drain pipes in case of geometrical variations of the pipe inlet orifices and zones with varied permeability. Using the potential theory, computational formulas are derived for the determination of the pipe inlet resistance characteristics under the aforementioned complex conditions.