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Search results for: Numerical spray modelling
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Mesoscopic modelling of strain localization in concrete
PublicationArtykuł omawia obliczenie lokalizacji odkształceń w elementach betonowych poddanych zginaniu. Obliczenia wykonano dla betonu na poziomie mezo przy zastosowaniu modelu zniszczeniowego z degradacją sztywności rozszerzonego o nielokalność. Zbadano wpływ zagęszczenia kruszywa, wielkość kruszywa, kształtu kruszywa oraz długości charakterystycznej na szerokość lokalizacji.
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Application and modelling of Shape-Memory Alloys for structural vibration control: State-of-the-art review
PublicationOne of the most essential components of structural design for civil engineers is to build a system that is resistant to environmental conditions such as harsh chemical environments, and catastrophic disasters like earthquakes and hurricanes. Under these circumstances and disturbances, conventional building materials such as steel and concrete may demonstrate inadequate performance in the form of corrosion, deterioration, oxidizing,...
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Improved maximum power point tracking algorithms by using numerical analysis techniques for photovoltaic systems
PublicationSolar photovoltaic (PV) panels generate optimal electricity when operating at the maximum power point (MPP). This study introduces a novel MPP tracking algorithm that leverages the numerical prowess of the predictor-corrector method, tailored to accommodate voltage and current fluctuations in PV panels resulting from variable environmental factors like solar irradiation and temperature. This paper delves into the intricate dynamics...
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EXPERIMENTAL AND NUMERICAL INVESTIGATIONS OF CONCRETE BEHAVIOUR AT MESO-LEVEL DURING QUASI-STATIC SPLITTING TENSION
PublicationThe paper describes experimental and numerical results of quasi-static splitting tensile tests on concrete specimens at meso-scale level. The loading strip was made of plywood or steel. Fracture in concrete was detected at the aggregate level by means of three non-destructive methods: 3D x-ray micro-computed tomography, 2D scanning electron microscope and manual 2D digital microscope. The discrete element method was used to directly...
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Surface sliding in human abdominal wall numerical models: Comparison of single-surface and multi-surface composites
PublicationDetermining mechanical properties of abdominal soft tissues requires a coupled experimental-numerical study, but first an appropriate numerical model needs to be built. Precise modeling of human abdominal wall mechanics is difficult because of its complicated multi-layer composition and large variation between specimens. There are several approaches concerning simplification of numerical models, but it is unclear how far one could...
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Numerical Analysis of the Unsteady Propeller Performance in the Ship Wake Modified by Different Wake Improvement Devices
PublicationThe paper presents summary of numerical analysis of the unsteady propeller forces and induced pressure pulses generated by the selected real propeller of 7000 tons product tanker, operating in five different wakefields including four inflenced by the different wake improvement devices. The results of the analysis are partly compared with experimental data and univocal conclusions about the optimum wake improvement device are presented.
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Numerical Study of the Impinging Jets Formed by an Injector with Different Nozzle Diameters
PublicationThe collision of two or more liquid jets may provide considerable atomisation and efficient mixing of injected substances at the same time. This phenomenon is used, among others, in rocket engines, where the fuel and oxidiser are introduced separately and almost immediately mixed through self-impingement. Depending on the injection and operating conditions, diverse configurations of impinging jets are used, such as doublets,...
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Operational Enhancement of Numerical Weather Prediction with Data from Real-time Satellite Images
PublicationNumerical weather prediction (NWP) is a rapidly expanding field of science, which is related to meteorology, remote sensing and computer science. Authors present methods of enhancing WRF EMS (Weather Research and Forecast Environmental Modeling System) weather prediction system using data from satellites equipped with AMSU sensor (Advanced Microwave Sounding Unit). The data is acquired with Department of Geoinformatics’ ground...
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Numerical Solution of the Two-Dimensional Richards Equation Using Alternate Splitting Methods for Dimensional Decomposition
PublicationResearch on seepage flow in the vadose zone has largely been driven by engineering and environmental problems affecting many fields of geotechnics, hydrology, and agricultural science. Mathematical modeling of the subsurface flow under unsaturated conditions is an essential part of water resource management and planning. In order to determine such subsurface flow, the two-dimensional (2D) Richards equation can be used. However,...
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EXPERIMENTAL AND NUMERICAL INVESTIGATION ON SPECIMEN GEOMETRY EFFECT ON THE CTOD VALUE FOR VL-E36 SHIPBUILDING STEEL
PublicationThere are special cases in the marine industry, where additional material tests, such as the fracture toughness test, must be performed. Additional fracture toughness tests, such as CTOD (Crack Tip Opening Displacement), are typically performed on three-point bend specimens. The dimension that defines all the specimen dimensions is the thickness of the material to be tested. It is recommended by classification societies (e.g. DNVGL)...
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Numerical analysis of the container vessel's self-propulsion at different rudder deflection angles
PublicationNowadays, CFD becomes one of the most commonly used research method in ship hydrodynamics, limited to the analyses of hull resistance in calm water. With continuously improving computing power and increasingly more accurate numerical methods it is possible to simulate more complex cases. State of the art CFD tools also enable development of new ways of assessing ship maneuvering performance. This paper presents an attempt on...
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Numerical study on seismic response of a base-isolated building modelled with shell elements
PublicationSeismic isolation is counted among the most popular and effective means of protecting structures against earthquake forces. Base isolators, like Lead-Rubber Bearings (LRB), High-Damping Rubber Bearings (HDB) or Friction Pendulum Systems (FPS) are extensively used in practice in many earthquake-prone regions of the world. The present paper reports the results obtained from the numerical study on seismic response of a base-isolated...
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Numerical analysis of the container vessel's self-propulsion at different rudder deflection angles
PublicationNowadays, CFD becomes one of the most commonly used research method in ship hydrodynamics, limited to the analyses of hull resistance in calm water. With continuously improving computing power and increasingly more accurate numerical methods it is possible to simulate more complex cases. State of the art CFD tools also enable development of new ways of assessing ship maneuvering performance. This paper presents an attempt on using...
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Modelling of Ship’s Heeling and Rolling for the Purpose of Gantry Control Improvement in the Course of Cargo Handling Operations in Sea Ports
PublicationThe paper presents two proposals of models of interaction between a ship and cargo being loaded or discharged by a gantry in port, in terms of heeling and rolling of the vessel. The main purpose of such modelling is the need for improvement of gantry control with regard to faster operations thanks to more accurate estimation of level and moment of cargo release from a gantry hook or spreader. The study may be the contribution to...
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An automatic selection of optimal recurrent neural network architecture for processes dynamics modelling purposes
PublicationA problem related to the development of algorithms designed to find the structure of artificial neural network used for behavioural (black-box) modelling of selected dynamic processes has been addressed in this paper. The research has included four original proposals of algorithms dedicated to neural network architecture search. Algorithms have been based on well-known optimisation techniques such as evolutionary algorithms and...
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Reduced-cost surrogate modelling of compact microwave components by two-level kriging interpolation
PublicationFull-wave electromagnetic (EM) analysis is a versatile tool for evaluating the performance of high-frequency components. Its potential drawback is its high computational cost, inhibiting the execution of EM-driven tasks requiring massive simulations. The applicability of equivalent network models is limited owing to the topological complexity of compact microstrip components because of EM cross-coupling effects. Development of...
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Building Information Modelling as an opportunity and risk for stakeholders involved in construction investment process
PublicationThe requirements to apply Building Information Modelling (BIM) in public investments worldwide are currently very high. Significant interest (sometimes formulated also as a requirement) in BIM technology can be observed also among private investors. Design technology that applies BIM is supported by many private investors due to its numerous advantages. A growing group of construction designers (steel, concrete and reinforced concrete...
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Polygons vs. clumps of discs: A numerical study of the influence of grain shape on the mechanical behaviour of granular materials
PublicationWe performed a series of numerical vertical compression tests on assemblies 01 20 granular material using a Discrete Element code and studied the results with regard to the grain shape. The samples consist of 5000 grains made from either 3 overlapping discs (clumps - grains with concavities) or six-edged polygons (convex grains). These two grain type have similar external envelope, which is a fund ion of a geometrical parameter...
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ORF Approximation in Numerical Analysis of Fractional Point Kinetics and Heat Exchange Model of Nuclear Reactor
PublicationThis paper presents results concerning numerical solutions of the fractional point kinetics (FPK) and heat exchange (HE) model for a nuclear reactor. The model consists of a nonlinear system of fractional and ordinary differential equations. Two methods to solve the model are compared. The first one applies Oustaloup Recursive Filter (ORF) and the second one applies Refined Oustaloup Recursive Filter (RORF). Simulation tests have...
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ORF Approximation in Numerical Analysis of Fractional Point Kinetics and Heat Exchange Model of Nuclear Reactor
PublicationThis paper presents results concerning numerical solutions of the fractional point kinetics (FPK) and heat exchange (HE) model for a nuclear reactor. The model consists of a nonlinear system of fractional and ordinary differential equations. Two methods to solve the model are compared. The first one applies Oustaloup Recursive Filter (ORF) and the second one applies Refined Oustaloup Recursive Filter (RORF). Simulation tests have...
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Numerical Simulations of Seepage in Dikes Using unsaturated and Two-Phase Flow Models
PublicationModeling of water flow in variably saturated porous media, including flood dikes, is often based on the Richards equation, which neglects the flow of pore air, assuming that it remains at constant atmospheric pressure. However, there is also evidence that the air flow can be important, especially when the connectivity between the pore air and atmospheric air is lost. In such cases a full two-phase air-water flow model should be...
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Minichannel and minigap classification criteria based on the aspect ratio of the minigeometry: A numerical study
PublicationA detailed numerical investigation has been carried out to analyze the diabatic flow distribution and velocity profile in 18 minigeometries with various aspect ratios for V-type and I-type flow configurations (for 36 cases) assuming ethanol as a working fluid. The aim of the study is to distinguish the value of the aspect ratio for which the flow in minigeometry starts to be two-dimensional (minigap). Cases with a constant Reynolds...
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Numerical Investigation on Dynamic Performance of a Multi-storey Steel Structure Model and Comparison with Experimental Results
PublicationShaking table testing is the most commonly adopted method to simulate earthquake forces. This approach allows us to analyze the dynamic performance and provides a valuable insight into the dynamics of building structures, which helps to improve their future safety and reliability. The present study aims to conduct a numerical evaluation of dynamic response of a multi-storey steel structure model, which was previously examined during...
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Numerical investigation on dynamic performance of a multi-storey steel structure model and comparison with experimental results
PublicationShaking table testing is the most commonly adopted method to simulate earthquake forces. This approach allows us to analyze the dynamic performance and provides a valuable insight into the dynamics of building structures, which helps to improve their future safety and reliability. The present study aims to conduct a numerical evaluation of dynamic response of a multi-storey steel structure model, which was previously examined during...
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Low-cost data-driven modelling of microwave components using domain confinement and PCA-based dimensionality reduction
PublicationFast data-driven surrogate models can be employed as replacements of computationally demanding full-wave electromagnetic simulations to facilitate the microwave design procedures. Unfortunately, practical application of surrogate modelling is often hindered by the curse of dimensionality and/or considerable nonlinearity of the component characteristics. This paper proposes a simple yet reliable approach to cost-efficient modelling...
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Numerical Model of Surface and Quasi-Spherical Sea Noise and Its Application to Analysis of DIFAR Systems
PublicationVarious types of passive sonar systems are used to detect submarines. These activities are complex and demanding. Therefore, computer simulations are most often used at the design stage of these systems. For this reason, it is also necessary to simulate the acoustic ambient noise of the sea. The article proposes a new numerical model of surface and quasi-spherical sea noise and presents its statistical parameters. The results of...
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TIME-DOMAIN NUMERICAL EVALUATION OF SHIP RESISTANCE AND MOTION IN REGULAR WAVES BY USING THE CFD URANS METHOD
PublicationTaking into account the International Maritime Organisation’s (IMO) strategy to radically reduce the GHG emitted by the shipping industry towards zero emission operation, today's assessment of ship behaviour in waves, its seakeeping characteristics and resistance and their interrelation with fuel consumption and emissions are one of the most attended research subject. There are three methods to conduct this analysis, which are...
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Numerical Comparison of Damping Amplification Effects Obtained in Neighborhood of a Mechanism Singular Position - Viscous and Electromagnetic Cases
PublicationIn the paper, results of numerical investigations are presented. A continuous beam is considered as the main vibrating element. Two energy dissipations methods are compared: viscous dampers and DC generators. To increase the damping effectiveness, velocity amplification is proposed, i.e., a mechanism is introduced between the beam and the damping element, and the mechanism configuration is set as closed to the singular position...
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Experimental and numerical study on polymer element used for reduction of temporary steel grandstand vibrations
PublicationThe purpose of the paper is to analyse the effectiveness of a polymer damper in reduction of a temporary steel grandstand vibrations through the experimental and numerical study. The damper considered in the investigation is constructed out of two L-shape steel members bonded with polymer mass of high damping properties. The element has been installed as a diagonal one at the back part of the structure. The method has been compared...
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Speed estimation of a car at impact with a W-beam guardrail using numerical simulations and machine learning
PublicationThis paper aimed at developing a new method of estimating the impact speed of a passenger car at the moment of a crash into a W-beam road safety barrier. The determination of such a speed based on the accident outcomes is demanding, because often there is no access to full accident data. However, accurate determination of the impact speed is one of the key elements in the reconstruction of road accidents. A machine learning algorithm...
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Modelling of residential sales price with kriging using different distance metrics in different correlation functions
PublicationThe modelling and estimation of sales prices based on economical conditions are important for housing sector especially in developing countries. Analysts are focused on the subject to analyze price movements and estimate the future trend of the sales prices for housing sector. In this study, we tried to generate a robust and efficient model related to the subject. Firstly, we investigated economic variables affecting housing sales...
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The elasto-plastic numerical study of crack initiation in notched PMMA specimens under uniaxial loading conditions – Tension and torsion
PublicationThis paper presents the results of FEM numerical calculations aimed at describing the plastic strain and stress fields under critical loading conditions: tensile force or torsional moment. The calculations were carried out with reference to the results of experimental tensile and torsional tests of flat PMMA specimens weakened with V-notches of different root radii: 0.5, 2 and 10 mm. The procedure for conducting nonlinear numerical...
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Nonlinear numerical simulation of earthquake-induced pounding between timber frame buildings
PublicationEarthquakes may induce serious dynamic loads acting on buildings, which can lead to damage or even destruction of the whole structure. In densely populated areas, it is quite common that buildings are located very close one to another which can result in pounding between them during ground motions. Due to the environmental awareness, multi-story timber frame buildings are gaining popularity and therefore there is a need to investigate...
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Numerical Studies on Propellers in Open Water and behind Hulls aiming to support the Evaluation of Propulsion Tests
PublicationA RANS based numerical analysis of propellers can contribute considerably to our understanding of propeller/hull interaction. It may also allow for a review of scaling procedures on results from experimental fluid dynamics (EFD). Using various RANS codes (Fluent, CFX, STAR-CCM+ and FreSCo+) on common test cases the authors first focused on propeller open water (POW) calculations. Next we simulated the propeller hull interaction...
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On Nonlinear Bending Study of a Piezo-Flexomagnetic Nanobeam Based on an Analytical-Numerical Solution
PublicationAmong various magneto-elastic phenomena, flexomagnetic (FM) coupling can be defined as a dependence between strain gradient and magnetic polarization and, contrariwise, elastic strain and magnetic field gradient. This feature is a higher-order one than piezomagnetic, which is the magnetic response to strain. At the nanoscale, where large strain gradients are expected, the FM effect is significant and could be even dominant. In...
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Modular Approach for Modelling Warming Up Process in Water Installations with Flow-Regulating Elements
PublicationThe paper presents a new method for modelling the warming up process of a water system with elements regulating the flow in a stochastic manner. The paper presents the basic equations describing the work of typical elements which the water installation is composed of. In the proposed method, a new computational algorithm was used in the form of an iterative procedure enabling the use of boundary conditions that can be stochastically...
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Could spray-dried microbeads with chitosan glutamate be considered as promising vaginal microbicide carriers? The effect of process variables on the in vitro functional and physicochemical characteristics
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Ethylcellulose in Organic Solution or Aqueous Dispersion Form in Designing Taste-Masked Microparticles by the Spray Drying Technique with a Model Bitter Drug: Rupatadine Fumarate
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A digital cartographic source for numerical models in hydrology
PublicationAutorzy prowadzą analizę wykorzystania i przydatności cyfrowych danych kartograficznych w rozwiązywaniu przestrzennych zagadnień hydrologicznych. Szczególne znaczenie dla prowadzonych analiz mają DTM i DEM. Są one źródłem bezpośrednich wielkości wejściowych modelu hydrologicznego i dodatkowo pozwalają na szersze możliwości prezentacji otrzymanego rozwiązania.
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Numerical and Experimental Study of Tidal Turbine Performance
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Numerical and Experimental Study of Tidal Turbine Performance
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Numerical modeling of wave-seabed-structure interaction.
PublicationPraca doktorska przedstawia propozycję nowoczesnego rozwiązania obciążeń hydraulicznych przy uwzględnieniu nieliniowych oddziaływań pomiędzy falą wodną, przepuszczalnym dnem i porowatą konstrukcją morską. Nabrzeże pionowe, falochron podwodny i falochron kompozytowy były obiektem eksperymentów numerycznych, których wyniki były weryfikowane przy użyciu wyników laboratoryjnych (niszczących i nieniszczących). Krótki przegląd bieżącej...
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Numerical-analytic methods for differential-algebraic systems
PublicationMetodę numeryczno-analityczną połączoną z metodą porównawczą zastosowano do układów równań różniczkowo-algebraicznych z linowymi warunkami brzegowymi otrzymując warunki dostateczne na istnienie rozwiązania. O prawych stronach zagadnienia zakładano warunek Lipschitza. Otrzymano oszacowania błędów. Problem z odchylonymi argumentami był również przedmiotem rozważań tej pracy.
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Monotone and numerical analytic- methods for differential equations.
PublicationPraca dotyczy problemu różniczkowo-całkowego (typu Fredholma) z ogólnym warunkiem początkowo-brzegowo-całkowym. W pierwszej części pracy, stosując metodę iteracji monotonicznych, sformułowano warunki dostateczne które gwarantują, że dyskutowany problem ma rozwiązanie ekstremalne w zbiorze generowanym przez dolne i górne rozwiązania. Rozważania teoretyczne poparto przykładem i dyskusją. W drugiej części pracy zastosowano metodę...
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On numerical calculation of acoustic field of plane source.
PublicationSkładowe harmoniczne wiązki akustycznej zostały obliczone na podstawie reprezentacji w postaci całek według teorii reprezentacji. Zastosowano nowe metody do obliczania całek od funkcji szybko oscylacyjnych.
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Numerical integration of a coupled Korteweg-deVries system
PublicationMetoda numeryczna została wprowadzona do rozwiązania ogólnych układów równańKorteweg´a- de Vries´a. Zastosowana do równania Hirota-Satsuma.
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Numerical simulations of S700MC laser and hybrid welding
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Numerical Simulation of Duplex Steel Multipass Welding
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Numerical analysis of scale effects in open propellers
PublicationArtykuł przedstawia numeryczne badania efektu skali powodującego różnice w charakterystykach hydrodynamicznych śrub okrętowych wyznaczonych dla skali rzeczywistej i dla skali modelowej. Zaprezentowano wyniki obliczeń dla trzech przykładowych śrub, pokazując poprawki na efekt skali wyznaczone według czterech różnych metod.
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Numerical simulation of energy buoy motion in wave
PublicationW pracy przedstawiono opis numerycznej metody modelowania ruchu boi energetycznej na fali. Wyniki obliczeń porównano z wynikami otrzymanymi z badań modelowych przeprowadzonych w basenie hydromechanicznym.