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Search results for: Numerical spray modelling
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Modelling of convective heat transfer in flow boiling.
PublicationW pracy przedstawiono rozważania dotyczące modelowania przepływu z wrzeniem w zastosowaniu do kanałów o małej średnicy. Stwierdzono,że stosowanie korelacji obowiązujących dla średnic konwencjonalnych nie sprawdza się z praktyką w przypadku małych średnic.
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Fractal analysis and modelling of gas bubble formation.
PublicationPrzedstawiono wyniki badań eksperymentalnych generowania pęcherzyków powietrznych z dysz o różnej średnicy, umieszczonych pod powierzchnią wody. Sygnał rejestrowany przez układ laser-fotodioda poddano analizie fraktalnej.
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Discussion of Modelling Perspectives for Complex Economic Systems.
PublicationW artykule opisano rolę modelowania w ekonomicznych systemach złożonych w kontekście trzech funkcji naukowych: opisu, wyjaśniania i przewidywania. Fazy dekompozycji i opisu jakościowego modelowanych systemów, w tym ekonomicznych, są nieodzowne w całym procesie.
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Information management. Modelling, analysis and simulation persepctive.
PublicationW książce poruszono zagadnienia związane z zarządzaniem informacją w społączeństwie informacyjnym. Szczególny nacisk położono na metody wspomagania przepływów informacji w systemach złożonych.
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Modelling and uncertainty in system analysis for safety assessment.
PublicationArtykuł obejmuje zagadnienia związane z modelowaniem i reprezentacją niepewności i ilościowych oszacowaniach ryzyka. Problem jest istotny w praktyce, ponieważ wystęopujhą wymagania przeprowadzenia ocen niepewności miar probabilistycznych i ryzyka. Dyskutuje się potencjalne żródła niepewności i dokonuje sie przeglądu podstaw teoretycznych reprezentacji niepewności. W modelowaniu systemów zawierających nieprecyzyjnie zdefiniowane...
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Traffic fatalities modelling using time-series.
PublicationReferat zawiera opis jednaj z metod analizowania trendów bezpieczeństwa ruchu drogowego opartej na teorii szeregów czasowych. Przedstawiono w nim aplikację tej metody do badania związku pomiędzy liczbą śmiertelnych ofiar wypadków drogowych w Polsce w latach 1991-2003 a wielkością bezrobocia w tym czasie.
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A nonlinear approach to modelling gas bubble deformation.
PublicationPrzedstawiono model wyjaśniający wpływ deformacji pęcherzyka na występowanie zjawiska chaosu podczas generowania pęcherzyków gazowych z pojedynczej dyszy zanurzonej w cieczy.
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Modelling of Flow Process in Small Diameter Tubes.
PublicationW pracy zastosowano standardowš korelację wrzenia w przepływie (wyprowadzonš dla rur o konwencjonalnych wymiarach) do przypadków wrzenia w rurach o małych rednicach. Porównanie wyników z danymi literaturowymi wykazało nieużytecznoć tej korelacji. Wykazano zatem potrzebę prowadzenia badań podstawowych celem uzyskania korelacji pozwalajšcej umiejętnie przewidywać warunki wymiany ciepła w kanałach o małych rednicach.
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Modelling of behavior of plain concrete using DEM
PublicationW artykule pokazano rozwój różnych zjawisk mikrostrukturalnych na poziomie kruszywa w betonie podczas jednoosiowego ściskania i rozciągania.. Obliczenia wykonano stosując metodę DEM. Wyniki na poziomie globalnym porównano doświadczalnymi. Szczególna uwagę zwrócono na propagację rys i szerokość lokalizacji odkształceń.
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Modelling the effect of composition on the tensile properties of concrete
PublicationRozdział omawia wyniki analizy mezoskopowej procesu pękania w betonie podczas zginania. Obliczenia wykonano na poziomie mezo wykorzystując model degradacji sztywności z nielokalnym osłabieniem. Zbadano wpływ właściwości kruszywa, stref przejściowych, nacięcia oraz długości charakterystycznej mikrostruktury na zachowanie sie betonu. Zaproponowano 2 metody określenia reprezentatywnego elementu objętościowego w betonie.
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FE modelling of brittle materials at the meso-scale
PublicationArtykuł omawia obliczanie lokalizacji odkształceń w elementach betonowych poddanych rozciąganiu. Obliczenia wykonano dla betonu na poziomie mezo. Obliczenia wykonano przy zastosowaniu modelu zniszczeniowego z degradacją sztywności rozszerzonego o nielokalność.
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Modelling AOB-NOB competition in shortcut nitrification compared with conventional nitrification-denitrification process
PublicationIn particular, mainstream deammonification and/or shortened nitrificationdenitrification via nitrite (so-called “nitrite shunt”) is a promising new treatment concept that has the potential to revolutionise how nitrogen removal is achieved at WWTPs. Understanding the role of the AOB/NOB competition in the nitrogen cycle in wastewater treatment systems will change operational strategies of the novel nitrogen removal processes. The...
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Numerical modeling and experimental validation of full-scale segment to support design of novel GFRP footbridge
PublicationThe paper contains analysis of full-scaled three meters long segment of a novel composite footbridge. Both numerical modeling and experimental validation were performed. Analyzed object is a shell type sandwich channel-like structure made of composite sandwich with GFRP laminates as a skin and PET foam as a core. Several static load schemes were performed including vertical and horizontal forces. In FEM analysis multilayered laminate...
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"Creating a numerical model of noise conditions based on the analysis of traffic volume changes in cities with low and medium structure.
PublicationThe subject of this research study is to analyze noise conditions of the selected area in the city of Gdańsk using data related to traffic volume changes during a day. This is because daily distribution of noise levels is much more helpful for noise control and reduction than traditional maps with Lden levels indicated. Calculations are made with the use of a numerical model developed at the Gdansk Univ. of Technology and implemented...
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"Creating a numerical model of noise conditions based on the analysis of traffic volume changes in cities with low and medium structure.
PublicationThe subject of this research study is to analyze noise conditions of the selected area in the city of Gdańsk using data related to traffic volume changes during a day. This is because daily distribution of noise levels is much more helpful for noise control and reduction than traditional maps with Lden levels indicated. Calculations are made with the use of a numerical model developed at the Gdansk Univ. of Technology and implemented...
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Assessment of tensile forces in Sopot Forest Opera membrane by in situ measurements and iterative numerical strategy for inverse problem
PublicationAssessment of tensile forces in newly build Sopot Forest Opera roofing membrane is presented. The procedure is based on in situ measurements and solution of the inverse problem by an iterative procedure. The goal of the analysis is to determine whether the stress state of the membrane is consistent with the design assumptions. The paper contains the description of measurements, used instruments, applied loadings, numerical investiga-tions...
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Corrosion damage identification based on the symmetry of propagating wavefield measured by a circular array of piezoelectric transducers: Theoretical, experimental and numerical studies
PublicationThe article investigates the results obtained from numerical simulations and experimental tests concerning the propagation of guided waves in corroded steel plates. Developing innovative methodologies for assessing corrosion-induced degradation is crucial for accurately diagnosing offshore and ship structures exposed to harsh environmental conditions. The main aim of the research is to analyze how surface irregularities affect...
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Numerical and experimental investigation of guided ultrasonic wave propagation in non-uniform plates with structural phase variations
PublicationThe article presents the results of numerical and experimental investigations of guided wave propagation in aluminum plates with variable thickness. The shapes of plate surfaces have been specially designed and manufactured using a CNC milling machine. The shapes of the plates were defined by sinusoidal functions varying in phase shift, which forced the changes in thickness variability alongside the propagation path. The main aim...
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Modelling of shear zones during quasi-static granular silo flow using material point method (MPM)
PublicationThe paper focuses on confined silo flow of cohesionless sand. The problem considered is a quasi-static flow in a plane strain model silo with parallel walls simulated with the material point method (MPM). The simulation used a non-local hypoplastic constitutive model. Initially, the paper validated the implemented numerical approach with basic element tests and a plane strain compression test. The subsequent MPM calculations for...
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REVERSE MODELLING OF MICROSEISMIC WAVES PROPAGATION FOR THE INTERPRETATION OF THE DATA FROM HYDRAULIC FRACTURING MONITORING IN POLAND
PublicationA hydraulic fracturing job was performed to stimulate gas flow from a horizontal wellbore located in Poland. The whole operation was overseen by means of microseismic monitoring. For this purpose, an array of 12000 geophones was deployed on ground in form of patches distributed unevenly in a region of 4km from the wellbore. The array was constantly recording seismic signals during whole fracturing processed. Such recorded signals...
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Determination of Thermophysical Parameters Involved in The Numerical Model to Predict the Temperature Field of Cast-In-Place Concrete Bridge Deck
PublicationThe paper dealswith a concept of a practical computationmethod to simulate the temperature distribution in an extradosed bridge deck. The main goal of the study is to develop a feasible model of hardening of concrete consistent with in-situ measurement capabilities. The presented investigations include laboratory tests of high performance concrete, measurements of temperature evolution in the bridge deck and above all, numerical...
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NUMERICAL SIMULATIONS OF HONING PROCESS OF THIN WALL CYLINDER LINERS, WITH CONSTANT AND WITH VARIABLE THICKNESS OF WALL OF HONED PARTS
PublicationNumerical simulations of honing process of thin-wall cylinder liners, with constant and with variable thickness of the wall of honed workpieces can improve and can help to conduct the experimental research of honing process and can improve the honing process. A very valuable research assumption, before performing the numerical analysis of computer simulation of honing process, is the measurement of the real geometry of the honing...
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MODELLING OF CONCRETE FRACTURE AT AGGREGATE LEVEL USING DEM BASED ON X-RAY mu CT IMAGES OF INTERNAL STRUCTURE
PublicationThe paper describes two-dimensional meso-scale numerical results of fracture in notched concrete beams under quasi-static three-point bending. Concrete was modelled as a random heterogeneous 4-phase material composed of aggregate particles, cement matrix, interfacial transitional zones (ITZs) and air voids. As a numerical approach, the discrete element method (DEM) was used. The concrete micro-structure in calculations was directly...
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Numerical analysis of lumbar spine injury during road safety barrier collision
PublicationPurpose: Enhancing road safety is a critical goal worldwide, necessitating the development of clear standards for road safety systems. This study focuses on lumbar spine (L-spine) compression injuries during collisions with concrete road safety barriers (RSBs). It aims to analyze internal forces during impact to understand L-spine injury biomechanics in such accidents. Methods: The research included a literature review, analyzing...
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Evaluation of the influence of the opening pressure of a marine Diesel engine injector on the results of numerical simulation of the working cycle and their comparison with the results of the laboratory experiment
PublicationThe article presents the results of a numerical simulation of the working process carried out in a diesel engine. In the applied utility program DIESEL-RK, the laboratory engine Farymann Diesel type D10 was implemented. A selected inoperability of its functional fuel supply system - reduced opening pressure of the injector pinj - was introduced. The values of adequate diagnostic parameters were determined: working gas temperature...
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A Numerical Study on Baseline-Free Damage Detection Using Frequency Steerable Acoustic Transducers
PublicationIn structural health monitoring (SHM) a considerable amount of damage detection algorithms based on guided waves (GW) have been developed. Most of them rely on extensive transducer networks, besides preliminary reference measurements of the structures. This originated a growing demand for hardware simplification and cost reduction of the wave-based SHM methods, driving the conception of new solutions enabling both: the reduction...
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Tackling Air Pollution in Cities with Modelling and Simulation: Remote Group Model Building as an Educational Tool Supporting System Dynamics Modelling
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Efficient Gradient-Based Algorithm with Numerical Derivatives for Expedited Optimization of Multi-Parameter Miniaturized Impedance Matching Transformers
PublicationFull-wave electromagnetic (EM) simulation tools have become ubiquitous in the design of microwave components. In some cases, e.g., miniaturized microstrip components, EM analysis is mandatory due to considera¬ble cross-coupling effects that cannot be accounted for otherwise (e.g., by means of equivalent circuits). These effects are particularly pronounced in the structures in¬volving slow-wave compact cells and their numerical...
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Quantitative assessment of the influence of tensile softening of concrete in beams under bending by numerical simulations with XFEM and cohesive cracks
PublicationResults of the numerical simulations of the size effect phenomenon for concrete in comparison with experimental data are presented. In-plane geometrically similar notched and unnotched beams under three-point bending are analyzed. EXtended Finite Element Method (XFEM) with a cohesive softening law is used. Comprehensive parametric study with the respect to the tensile strength and the initial fracture energy is performed. Sensitivity...
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Mechanics of mesh implanted into abdominal wall under repetitive load. Experimental and numerical study
PublicationThere are a number of papers discussing medical and mechanical aspects of ventral hernia management. Despite intensive work on the problem understanding, recurrences of the sickness still happen too often. For that reason new aspects of the problem must be considered. In this paper, a change in the abdominal implant’s stiffness is discussed, which is caused by cyclic loading. Such loading influence abdominal implant e.g. while...
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Numerical investigation on behaviour of cylindrical steel tanks during mining tremors and moderate earthquakes
PublicationCylindrical steel tanks are important components of industrial facilities. Their safety becomes a crucial issue since any failure may cause catastrophic consequences. The aim of the paper is to show the results of comprehensive FEM numerical investigation focused on the response of cylindrical steel tanks under mining tremors and moderate earthquakes. The effects of different levels of liquid filling, the influence of non-uniform...
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Modelling of subarachnoid space width changes in apnoea resulting as a function of blood flow parameters
PublicationDuring apnoea, the pial artery is subjected to two opposite physiological processes: vasoconstriction due to elevated blood pressure and vasorelaxation driven by rising pH in the brain parenchyma. We hypothesized that the pial artery response to apnoea may vary, depending on which process dominate. Apnoea experiments were performed in a group of 19 healthy, non-smoking volunteers (9 men and 10 women). The following parameters...
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Examples of numerical simulations of two-dimensional unsaturated flow with VS2DI code using different interblock conductivity averaging schemes
PublicationFlow in unsaturated porous media is commonly described by the Richards equation. This equation is strongly nonlinear due to interrelationships between water pressure head (negative in unsaturated conditions), water content and hydraulic conductivity. The accuracy of numerical solution of the Richards equation often depends on the method used to estimate average hydraulic conductivity between neighboring nodes or cells of the numerical...
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Numerical investigations of discrete crack propagation in Montevideo splitting test using cohesive elements and real concrete micro-structure
PublicationThe paper is aimed at accurately predicting the discrete fracture process in concrete specimens under complex stress states in two dimensional (2D) simulations. Plain concrete specimens subjected to Montevideo splitting test (MVD) were used for consideration due to non-negligible shear stresses impact in this type of test. In order to reflect the heterogeneous nature of the concrete, the meso-structure of the samples was included...
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Evaluation and behaviour of slowly biodegradable substrate on mathematical modelling of oxygen uptake rate in activated sludge systems
PublicationThe effect of the readily biodegradable (Ss) fraction in activated sludge systems has been extensively investigated, but only minor information can be found about the effect of Xs on OUR in activated sludge systems. The aim of this study was to determine the evaluation and behaviour of Xs on mathematical modelling of OUR using ASM2d and its modification. The essential study was divided into two major parts: experimental investigation...
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A numerical model to simulate the motion of a lifesaving module during its launching from the ship’s stern ramp
PublicationThe article presents a numerical model of object motion in six degrees of freedom (DoF) which is intended to be used to simulate 3D motion of a lifesaving module during its launching from a ship using a stern ramp in rough sea. The model, of relatively high complexity, takes into account both the motion of the ship on water in changing sea conditions, and the relative motion of the ramp with respect to the ship. The motion of the...
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Numerical modeling of hydrodynamics and sediment transport—an integrated approach
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Aluminium Profile Reinforced with Carbon Fibre: Numerical Analysis
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Numerical methods for systems of nonlinear differential functional equations
PublicationPraca dotyczy zagadnień początkowo brzegowych dla nieliniowych układów różniczkowo funkcyjnych. Rozważana jest aproksymacja rozwiązań rozważanego problemu różniczkowo funkcyjnego przez rozwiązania odpowiedniego problemu różnicowego. W pracy analizowana jest zbieżność prezentowanych metod. Dowód zbieżności opiera się na technice porównawczej z nieliniowym oszacowaniem typu Perron'a dla danych operatorów.
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Numerical analysis of elastic wave propagation in unbounded structures
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Implemetation of the measured shell geometric imperfections to the numerical model
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Mathematical model and numerical calculations of the pelagic trawl system
PublicationW pracy przedstawiono matematyczny model ruchu środka ciężkości zestawu do trałowania pelagicznego wraz z wyznaczaniem jego parametrów geometrycznych. Pokazano także sposób rozwiązania i przykładowe wyniki obliczeń numerycznych. Opracowany program komputerowy może być wykorzystywany do wyznaczania optymalnych parametrów pracy dla zapewnienia bezpiecznych, efektywnych i ekologicznych połowów pelagicznych
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Application of Numerical Simulations on 10GN2MFA Steel Multilayer Welding
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Numerical Simulations of X22CrMoV12-1 Steel Multilayer Welding
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Heat Source Models in Numerical Simulations of Laser Welding
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Numerical analysis of the influence of a Gyrotron's cavity walls curvature
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Numerical mesoscopic analysis of fracture in fine-grained concrete
PublicationArtykuł omawia wyniki analizy mezoskopowej procesu pękania w betonie podczas zginania. Obliczenia wykonano na poziomie mezo wykorzystując model degradacji sztywności z nielokalnym osłabieniem. Zbadano wpływ właściwości kruszywa, stref przejściowych, nacięcia oraz długości charakterystycznej mikrostruktury na zachowanie sie betonu.
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Numerical investigations of the nonlinear waves generation in a bubble layer
PublicationRozważano zagadnienie propagacji fal różnych częstotliwości wewnątrz warstwy z pęcherzykami. Przedstawiono model matematyczny zjawiska oraz wyniki badań teoretycznych. Badano zmiany widma fali bieżącej i odbitej jak również zmiany amplitud wybranych harmonicznych ciśnienia tych fal w funkcji grubości warstwy i koncentracji pęcherzyków.
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Numerical modeling of ice jam formation in the Włocławek reservoir
PublicationArtykuł opisuje zjawisko powstawania zatoru lodowego w zbiorniku przepływowym przy użyciu dwuwymiarowego modelu DynaRICE. Analizowany proces został przeanalizowany na przykładzie zatoru lodowego, który utworzył się na zbiorniku Włocławek w syczniu 1982 roku. Przeprowadzone obliczenia pokazały, że zator utworzyła się z lodu powierzchniowego. Efekt termiczny i tworzenie się śryżu w zbiorniku został pominięty jako drugorzędny. Wyniki...
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Numerical modeling of the nonlinear wave propagation in a bubble layer
PublicationRozważano zagadnienie propagacji fali wewnątrz warstwy z pęcherzykami. Omówiono model matematyczny, przedstawiono przykładowe wyniki badań teoretycznych. Analizowano zmiany ciśnienia wewnątrz warstwy, falę odbitą i bieżącą w ośrodku otaczającym, badano gęstość widmową mocy. Badania teoretyczne przeprowadzono dla różnych grubości warstwy, koncentracji pęcherzyków i wartości parametrów fali padającej.