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Wyniki wyszukiwania dla: numerical%20analysis
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Expedited antenna optimization with numerical derivatives and gradient change tracking
PublikacjaDesign automation has been playing an increasing role in the development of novel antenna structures for various applications. One of its aspects is electromagnetic (EM)-driven design closure, typically applied upon establishing the antenna topology, and aiming at adjustment of geometry parameters to boost the performance figures as much as possible. Parametric optimization is often realized using local methods given usually reasonable...
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Numerical Study of Concrete Mesostructure Effect on Lamb Wave Propagation
PublikacjaThe article presents the results of the numerical investigation of Lamb wave propagation in concrete plates while taking into account the complex concrete mesostructure. Several concrete models with randomly distributed aggregates were generated with the use of the Monte Carlo method. The influence of aggregate ratio and particle size on dispersion curves representing Lamb wave modes was analyzed. The results obtained for heterogeneous...
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The role of numerical tests in assessing road restraint system functionality
PublikacjaKey to understanding the needs and building road infrastructure management tools to prevent and mitigate run-off-road accidents is to identify hazards and their sources which are a result of wrong design, construction, and installation of road restraint systems. Building such tools requires advanced studies with field tests, simulations and models to demonstrate the effects of selected parameters on road user safety. The research...
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Dynamic tests of composite footbridge segment – experimental and numerical studies
PublikacjaExperimental dynamic tests and numerical simulations of a 3 meters long segment of a footbridge made of polymer composites are presented in the paper. The span-length is reduced, however dimensions of cross-section are the same as the target footbridge. The segment structure is made of sandwich panels, which consist of fibre reinforced polymer (GFRP) laminates (skins) and a PET foam (core). The first part of the paper contains...
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Numerical investigation on the performance of a small counter-rotating wind turbine
PublikacjaThe article presents the results of the investigation on the performance of a small counter-rotating wind turbine. The wind turbine has been simulated using Computational Fluid Dynamics methods. Actuator Line Model has been successfully used to represent rotors in the computational domain. A parametric study has been carried out, taking into account changes in the tip speed ratio of the rotors while maintaining a constant distance...
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Experimental and numerical studies of double corrugated steel arch panels
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Numerical modeling of force and contact networks in fragmented sea ice
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Numerical modelling of thermodynamics and dynamics of sea ice in the Baltic Sea
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NUMERICAL MODELLING AND EXPERIMENTATION OF HISTORICAL CARPENTRY CORNER LOG JOINTS
PublikacjaThe main purpose of this research is to determine the stress distributions on the contact surfaces between the logs of the historical carpentry corner joints. The additional purpose is to compare the stress distribution for four different boundary conditions in the case of dry and wet pine wood. The paper presents the results of numerical analysis of the shortcorner dovetail connection and the saddle notch corner joint, which are...
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Numerical algorithms of planning safe ship trajectories for ARPA systems
PublikacjaTeza rozprawy: ''Połączenie odpowiedniej miary ryzyka kolizji obiektów i metody unikania kolizji za pomocą manewru niezbędnego pozwala na opracowanie szybkiej, efektywnej i prostej w implementacji metody planowania bezpiecznych trajektorii statków dla systemów ARPA, uwzględniającej dowolną zadaną domenę obiektu. Dobór kształtu domeny obiektu ma znaczny wpływ na zgodność wynikowej trajektorii z regułami MPDM. Minimalizacja liczby...
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Numerical approximations of parabolic functional differential equations on unbounded domains
PublikacjaSkonstruowano schematy różnicowe zagadnień początkowych dla nieliniowych parabolicznych równań różniczkowo funkcyjnych. Przedstawiono twierdzenie o oszacowaniu błędu rozwiązań przybliżonych dla równań różnicowo funkcyjnych typu Volterry z niewiadomą funkcją kilku zmiennych. Udowodniono twierdzenie o zbieżności jawnych schematów różnicowych. Podano przykłady numeryczne.
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Numerical heat transfer model in skin burn depth simulations
PublikacjaW artykule przedstawiono numeryczny model wymiany ciepła zachodzącej w tkance skórnej . Wyniki symulacji na modelu zostały porównane z wynikami pomiarów In vivo na zwierzętach.
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Numerical Simulations of Laser and Hybrid S700MC T-Joint Welding
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Computational Techniques in Numerical Simulations of Arc and Laser Welding Processes
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Measurements and numerical simulations of laser hardening and remelting thermal cycles
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A numerical scale to assess the outcomes of metabolic/bariatric surgery (NOMS)
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APPLICATION OF NUMERICAL SIMULATIONS ON X10CRWMOVNB9-2 STEEL MULTILAYER WELDING
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Numerical study of lasing modes of periodically structured active nanowires
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On convergence and stability of a numerical scheme of Coupled Nonlinear Schrödinger Equations
PublikacjaRozważamy rozwiązania numeryczne układu sprężynowych równań nieliniowych Schrödingera. Udowodniliśmy stabilność i zbieżność. Testujemy za pomocą rozwiązań solitonowych.
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Multiacces quantum communication and product higher rank numerical range
PublikacjaIn the present paper we initiate the study of the product higher rank numerical range. The latter, being a variant of the higher rank numerical range, is a natural tool for study- ing a construction of quantum error correction codes for multiple access channels. We review properties of this set and relate it to other numerical ranges, which were recently introduced in the literature. Further, the concept is applied to the construction...
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Balance error generated by numerical diffusion in the solution of Muskingum equation
PublikacjaIn the paper the conservative properties of the lumped hydrological models with variable parameters are discussed. It is shown that in the case of the non-linear Muskingum equation the mass balance is not satisfied. The study indicates that the mass balance errors are caused by the improper form of equation and by the numerical diffusion which is generated in the solution. It has been shown that the classical way of derivation...
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Numerical Algorithms of Planning Safe Ship Trajectories for ARPA Systems
PublikacjaGłównym celem pracy było zaprojektowanie metody znajdowania bezpiecznych trajektorii statków, która byłaby prosta w implementacji, szybka (niska złożoność obliczeniowa)i deterministyczna, elastyczna (umożliwiałaby zastosowanie dowolnej domeny). Aby zrealizować cel należało zbadać bieżący stan wiedzy w dziedzinie,zaprojektować nową metodę, zaimplementować metodę (wraz ze wszystkimi niezbędnymi algorytmami) w środowisku programistycznym...
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Comparison of experimental and numerical results on metallic plates subjected to explosions
PublikacjaA comparative study of dynamic response including damage and rupture processes of thin metallic plates subjected to shockwave impulses - explosions is presented. The results of the finite element numerical analysis are related to experiments. Due to high strain rate during explosions the elasto-viscoplastic Chaboches constitutive law including damage effects has been applied. For the assumed model proper material parameters identification...
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Numerical Simulation of Open Channel Flow between Bridge Piers
PublikacjaPrzedstawiono dwuwymiarowy model przepływu wody płytkiej, który wykorzystano do symulacji przepływu wody w kanale otwartym w rejonie przekroju mostowego. Równania przepływu rozwiązano metodą objętości skończonych. Wyniki symulacji ruchu wody pomiędzy filarami mostowymi porównano z pomiarami laboratoryjnymi przeprowadzonymi w Laboratorium Hydrauliki i Inżynierii Środowiska politechniki Gdańskiej. Zgodność uzyskanych wyników obliczeń...
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Numerical study of turbulent flow and heat transfer of nanofluids in pipes
PublikacjaIn this work, Nusselt number and friction factor are calculated numerically for turbulent pipe flow (6 000 < Re < 12 000) with constant heat flux boundary condition using nanofluids. The nanofluid is modelled with the single-phase approach and the simulation results are compared with experimental data of Vajjha et al. [1]. Ethylene glycol and water, 60:40 EG/W mass ratio, as base fluid and SiO2 nanoparticles are used as nanofluid...
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Numerical solution of fractional neutron point kinetics in nuclear reactor
PublikacjaThis paper presents results concerning solutions of the fractional neutron point kinetics model for a nuclear reactor. Proposed model consists of a bilinear system of fractional and ordinary differential equations. Three methods to solve the model are presented and compared. The first one entails application of discrete Grünwald-Letnikov definition of the fractional derivative in the model. Second involves building an analog scheme...
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Design and numerical testing of 5-box gfrp shell footbridge
PublikacjaThe paper formulates new design conditions for composite footbridges, taking into account the material and structural specificity of these objects, i.e. the strength condition, the serviceability condition and the frequency condition. A GFRP composite footbridge labelled with CFB2 code has been designed, with the original superstructure in the form of an opened-closed 5-box girder. The foot and cycle track bridge is simply supported,...
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A COMPUTATIONAL ALGORITHM FOR THE NUMERICAL SOLUTION OF NONLINEAR FRACTIONAL INTEGRAL EQUATIONS
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Numerical modelling of conical wave formation in multimode optical fibers
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Design and numerical study of turbines operating with MDM as working fluid
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Numerical Simulation of Operating Parameters of the Ground Source Heat Pump
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Numerical modelling and experimental verification of compressible squeeze film pressure
PublikacjaThe validity of using the Reynolds equation for compressible squeeze film pressure was tested with computational fluid dynamics (CFD). A squeeze film air bearing was instrumented with pressure sensors and non-contacting displacement probes to provide transient measurements of film thickness and pressure. The film thickness measurements also provided input parameters to the numerical prediction. However, numerical results showed...
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Multimode systems of nonlinear equations: derivation, integrability, and numerical solutions
PublikacjaWe consider the propagation of electromagnetic pulses in isotropic media taking a third-order nonlinearityinto account. We develop a method for transforming Maxwell's equations based on a complete set ofprojection operators corresponding to wave-dispersion branches (in a waveguide or in matter) with thepropagation direction taken into account. The most important result of applying the method is a systemof equations describing the...
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Experimental and numerical investigations for GPR evaluation of reinforced concrete footbridge
PublikacjaThe GPR method has increasingly found application in non-destructive testing of reinforced concrete structures. This paper presents the new approach of modelling of the electromagnetic wave propagation for reinforced concrete structures with a complex system of the reinforcement. Simulations of the GPR field were performed on a three-dimensional model of a footbridge using the FDTD method. Numerical maps were compared with results...
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Monitoring of concrete curing in extradosed bridge supported by numerical simulation
PublikacjaThe paper describes a mathematical model of concrete curing taking into account kinetics of setting reactions. The numerical model is implemented in the author’s program that was used to monitor thermal effects recorded in the concrete bottom plate of the extradosed bridge. Numerical approach was verified by experimental measurements and used for assessment of the current compressive strength due to degree of hydration of fresh...
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Excavation induced cast iron pipeline failure – a numerical study
PublikacjaNumerical study on impact of an unsecured excavation on an underground pipeline. Analysis focused on investigation of pipeline displacement generated by soil movement caused by excavation and heavy traffic. Numerical calculations and soil parameter sensitivity analysis based on Finite Element Method. Some comparisons of results with real-life failure cases.
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Numerical modeling of sound intensity distributions around acoustic transducer
PublikacjaThe aim of this research study is to measure, simulate and compare sound intensity distribution generated by the acoustic transducers of the loudspeaker. The comparison of the gathered data allows for validating the numerical model of the acoustic radiation. An accurate model of a sound source is necessary in mathematical modeling of the sound field distribution near the scattering obstacles. An example of such obstacle is a human...
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Numerical Study of Turbulent Flow and Heat Transfer of Nanofluids in Pipes
PublikacjaIn this work, Nusselt number and friction factor are calculated numerically for turbulent pipe flow (Reynolds number between 6000 and 12000) with constant heat flux boundary condition using nanofluids. The nanofluid is modelled with the single-phase approach and the simulation results are compared with experimental data. Ethylene glycol and water, 60:40 EG/W mass ratio, as base fluid and SiO2 nanoparticles are used as nanofluid...
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Numerical Characterization of Thresholds for the Focusing 1d Nonlinear Schrödinger Equation
PublikacjaThe focusing nonlinear Schrödinger equation arises in various physical phenomena and it is therefore of interest to determine mathematical conditions on the initial data that guarantee whether the corresponding solution will blow up in finite time or exist globally in time. We focus on solutions to the mass‐supercritical nonlinear Schrödinger equation (1) in 1D case. In particular, we investigate numerical thresholds between blow...
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DEVELOPMENT OF A COUPLED NUMERICAL AND EXPERIMENTAL APPROACH TO HYDRODYNAMIC NOISE ESTIMATION
PublikacjaThe hydroacoustic signature of ships' propellers can be estimated experimentally through measurements of cavitation-induced pressure fluctuations and the corresponding noise distributions at model scale. These measurements need to be performed in a cavitation tunnel under the propellers operating conditions and are quite sensitive and challenging to perform with sufficient accuracy. In comparison, the numerical approach can be...
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Numerical Simulations of Hydrodynamic Open-Water Characteristics of a Ship Propeller
PublikacjaThe paper presents the results of numerical simulations of ship propeller operation bearing the name of Propeller Open Water (POW) Tests. The object of tests was a sample ship propeller (PPTC1), the geometrical and kinematic data of which are available, along with the results of model tests, on the official page of the research centre involved in the measurements. The research aimed at verifying the correctness of results of numerical...
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Numerical modelling of 3D printout using line (1D) elements
PublikacjaA proposition of some numerical modelling of the 3D printout is presented in the paper. The proposed model is composed of some 1D elements. The resulting numerical model of the infill consist of beam, spring and rigid elements. Obtained results confirm correctness of the proposed modelling method. Two methods of estimation of the spring parameters are proposed in the paper. In the first method, mechanical properties of the connecting...
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Experimental study and numerical optimization of tensegrity domes – A case study
PublikacjaThe paper deals with the design, experimental analysis and numerical optimization of tensegrity dome models. Two structures are analyzed – a Geiger system dome (preliminary dome), with PVC-U bars and PA6/PP/PET tendons and a Fuller system dome (target dome), with wooden bars and steel cables as tendons. All used materials are experimentally tested in terms of Young's modulus and yield stress values, the compressed bars are also...
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Numerical simulation of cold flow and combustion in a swirl stabilized combustor
PublikacjaA numerical simulation model was developed to investigate the cold flow and combustion using Ansys FLUENT 2021R1. The governing equations were solved using the pressure-based method, and pressure–velocity coupling was performed using the SIMPLE method. To model the turbulent process, the RSM model was used. Non-premixed model is chosen to solve the chemical kinetics between fuel and oxigen. Radiation heat transfer was calculated...
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Numerical prediction of steady and unsteady tip vortex cavitation on hydrofoils
PublikacjaArtykuł przedstawia metodę numeryczną do wyznaczania kawitujących wirów wierzchołkowych powstających za płatami nośnymi. Metoda ta jest oparta na rozwiązywanie dwufazowego turbulentnego przepływu cieczy lepkiej. Pozwala ona wyznaczyć geometrię kawitującego wiru dla różnych geometrii płata nośnego i dla różnych parametrów przepływu. Pokazano porównanie wyników obliczeń z pomiarami i rejestracjami wykonanymi na modelu płata w tunelu...
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Simplified Numerical Model for Transient Flow of Slurries at Low Concentration
PublikacjaRapid transients are particularly dangerous in industrial hydro-transport systems, where solid-liquid mixtures are transported via long pressure pipelines. A mathematical description of such flow is difficult due to the complexity of phenomena and difficulties in determining parameters. The main aim of the study was to examine the influence of the simplified mixture density and wave celerity description on satisfactory reproduction...
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A Numerical Model Study on Grasse River Ice Control Structures
PublikacjaIce jams in the Grasse River have caused the erosion of capping material designed to prevent the resurfacing of the bed sediment in the PCB-contaminated area. Two in-stream ice-control structures are proposed to avoid the jam-induced erosion of the capping material. These two ice-control options are a pier-type ice-control structure and a reconstruction of a small hydropower dam upstream of the capping site. A numerical model study...
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Experimental and numerical identification of corrosion degradation of ageing structural components
PublikacjaThe study presents experimental and numerical identification of corrosion degradation of thin-walled structural components employing guided wave propagation. The steel structural components are subjected to through-thickness varying corrosion degradation levels. The developed approach using the non-destructive guided wave-propagation quantifies the equivalent average corrosion degradation level by exploring a limited number of...
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Numerical method of bicharacteristics for quasilinear hyperbolic functional differential systems
PublikacjaPraca dotyczy numerycznej aproksymacji rozwiązań zagadnień początkowo brzegowych dla układów quasiliniowych równań różniczkowo funkcyjnych pierwszego rzędu. Stosuje się metodę różnicową typu Eulera. Siatka otrzymywana jest za pomocą numerycznego rozwiązywania równań różniczkowo funkcyjnych bicharakterystyk.Stabilność schematu różnicowego jest dowodzona metodą porównawczą. O danych funkcjach zakłada się, że spełniają nieliniowe...
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NUMERICAL ESTIMATION OF HULL HYDRODYNAMIC DERIVATIVES IN SHIP MANOUVERING PREDICTION
PublikacjaOperating in crowded waterways pose a risk of accidents and disasters due to maneuvering limitations of the ship. In order to predict ship’s maneuvering characteristics at the design stage, model tests are often executed as the most accurate prediction tool. Two approaches can be distinguished here: free running model tests and numerical simulations based on planar motion model with the use of hydrodynamic derivatives obtained...