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Search results for: fluid flow measurement
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Fluid Mechanics, W/C, EaPE (Dezhou), sem.5, zimowy 23/24 (PG_00059698)
e-Learning CoursesObjective of the subject is to supply the student with the theoretical and practical knowledge, enabling him to solve engineering computational and experimental problems related to fluid mechanics.
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MODELLING OF TRANSIENT FLOW IN STORM SEWERS
PublicationThe paper focuses on the assessment of second-order explicit numerical scheme for unsteady flows in sewers. In order to simulate the pressurized flow the 'Preissmann slot' concept is implemented. For simulation of the transcritical flow the original and improved McCormack scheme is used. The calculated results are compared with numerical solutions and laboratory measurements published in the technical literature. Moreover, the...
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EXPERIMENTAL VERIFICATION OF THE METHOD OF FLOW BOILING AND FLOW CONDENSATION HEAT TRANSFER PREDICTION FOR SELECTED FLUIDS
PublicationIn the paper presented are the results of calculations using authors own model to predict heat transfer coefficient during flow boiling of different refrigerants. The experimental data from various research studies from literature were collected. Calculations were conducted for a full range of quality variation and a wide range of mass velocity. The aim of the study was to test the sensitivity of the in- house developed model....
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Centrifugal magnetic fluid seals
PublicationSeals perform an important and at times overlooked function in a lubricant system. They prevent or minimize the movement of the lubricant between two surfaces and also minimize the level of contamination in the system. Seals are divided into static and dynamic types. Static seals operate in systems where the mating surfaces do not move relative to each other. In contrast, dynamic seals operate under conditions where the mating surfaces...
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Remote current measurement with FPGA digital processing
PublicationThe work presents an implementation of a modular measurement and control systemthat controls variants of mains supply of 230V electrical equipment. The system allowsto supervise power consumption in the office electronic equipment. The system detectsthe instant of the reduced power consumption by a device and makes possible itsswitch-off in order to reduce energy cost. The current is measured with integratedcurrent/voltage converters....
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On a comparison principle and the uniqueness of spectral flow
PublicationThe spectral flow is a well-known quantity in spectral theory that measures the variation of spectra about 0 along paths of selfadjoint Fredholm operators. The aim of this work is twofold. Firstly, we consider homotopy invariance properties of the spectral flow and establish a simple formula which comprises its classical homotopy invariance and yields a comparison theorem for the spectral flow under compact perturbations. We apply...
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A concept of measurement system based on the Z-Wave standard
PublicationIn the paper a new concept of measurement system based on the Z-Wave standard is presented. This standard is dedicated to use mainly in home automation systems, but its properties enable to use it in dispersed measurement systems and support wireless communication between measurement nodes in a mesh-type network. In the paper basic metrological aspects of the Z-Wave standard and an example of impedance measurement system are discussed.
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Interaction Between Storm Water Conduit Flow and Overland Flow for Numerical Modelling of Urban Area Inundation
PublicationNowadays we can observe increasing frequency of inundations in cities. This makes accurate predicting of inundations more important than ever. Numerical modeling of this issue requires complex approach with simultaneous calculations of pipe flow and surface flow. In this paper, after a short review of known methods used for solving pipe and surface flow, we will try to answer the question if presented methods would be sufficiently...
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Flow Maps and Flow Patterns of R1233zd(E) in a Circular Minichannel at Low, Medium and High Values of Saturation Pressure
PublicationThere is a gap in knowledge regarding the flow pattern of low-boiling working fluids in the range of high saturation temperatures (above 120°C) and medium and high reduced pressures (0.5-0.9). Data are present in the literature for similar values of reduced pressures, but for lower values of saturation temperature. This is due to the existing refrigeration applications of these working fluids. At high values of reduced pressure,...
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MOBILITY OF SHALE DRILL CUTTINGS CONSTITUENTS
PublicationThis study focuses on the abundance and mobility of metals and trace elements from shale drill cuttings into the water, being the main component of hydraulic fracturing fluid. The relationship between composition of the shale rock and the potential element release during standard water-based leaching tests was characterized by means of X-Ray Fluorescence spectroscopy (XRF). The XRF analysis confirmed the assumption of shales constituents...
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HYDROSTATIC THRUST BEARING WITH REDUCED POWER LOSSES
PublicationIn many cases in rotating machinery, axial load is carried by tilting pad thrust bearings which have been developed since the beginning of 20th century. For high reliability and simplicity, most commonly the bearings are bath lubricated. In the times of sustainable development, however, minimization of friction losses becomes an important criterion for machinery assessment, and a strategic goal of their development. Performed calculations,...
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Badania teoretyczne i doświadczalne rozkładu temperatur w hydrodynamicznym łożysku wzdłużnym
PublicationW referacie zaprezentowano przykładowe wyniki obliczeń uzyskane z wykorzystaniem rozwijanej w Politechnice Gdańskiej nowej metody oceny własności hydrodynamicznych łożysk wzdłużnych. Bazuje ona na wykorzystaniu techniki automatycznej wymiany informacji pomiędzy uwzględnianymi w analizach problemów obliczeń łożyskowych obszarami zadania tj. płynowym i strukturalnym, wykorzystując w tym celu dostępne programy obliczeniowe MES (technika...
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Scalable Measurement System for Multiple Impedance Gas Sensors
PublicationAuthor proposes scalable architecture of the measurement system for gas sensor with impedance dependance of the gas concentration. The main part of the system is a single-board impedance analyser. The number of analysers working in parallel can be configured according to specific application. The system is controlled by a single computer which organises the measurement cycle and store the acquired measurement data. The system is...
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Experimental and Computational Multiphase Flow
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Organic Rankine cycle as bottoming cycle to a combined Brayton and Clausius - Rankine cycle
PublicationA preliminary evaluation has been made of a possibility of bottoming of a conventional Brayton cycle cooperating with the CHP power plant with the organic Rankine cycle installation. Such solution contributes to the possibility of annual operation of that power plant, except of operation only in periods when there is a demand for the heat. Additional benefit would be the fact that an optimized backpressure steam cycle has the advantage...
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Measurements and Measurement Systems [WIMiO][2023/24]
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Numerical Simulations for Transonic Flow in Control Valve
PublicationResults of numerical simulations for transonic flow in control valve are presented. The valve is the main part of an adaptive pneumatic shock absorber. Flow structure in the valve domain and the influence of the flow non-uniformity in the valve on a mass flow rate is investigated. Numerical simulation results are compared with experimental data.
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Flow Analysis of a Kaplan Turbine
PublicationThis monograph is a guide to a method of experimental and numerical flow investigations for Kaplan - type turbines. The numerical calculations were compared with the test results of the model Kaplan turbine. The tests were carried out on the model test rig in the Gdańsk University of Technology. The turbine has been thoroughly experimentally investigated, resulting in the identification of optimum setting combination of the stator...
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Discrete measurement of fault-arc velocity
PublicationOpisano metodę dyskretnego pomiaru prędkości jednofazowego łuku awaryjnego poruszającego się w płaskim, poziomym układzie szyn. Badania przeprowadzono za pomocą punktowych czujników optycznych rozmieszczonych równomiernie wzdłuż szyn. Podano opis układu, jego charakterystykę, wpływ obszaru zjonizowanego na uzyskiwane wyniki i zależności między obserwowanymi wielkościami.
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Method of earth fault loop impedance measurement without nuisance tripping of RCDs in 3-phase low-voltage circuits
PublicationVerification of electrical safety in low-voltage power systems includes the measurement of earth fault loop impedance. This measurement is performed to verify the effectiveness of protection against indirect contact. The widespread classic methods and meters use a relatively high value of the measuring current (5–20) A, so that they are a source of nuisance tripping of residual current devices (RCDs). The meters dedicated to circuits...
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Synchro-photogrammetry in the measurement of objects in motion - the case study
PublicationSynchronous photographs and digital photogrammetry methods in a measurement of objects in motion - the experiment. In the following paper, a case study example of a photogrammetric method based on synchronous digital photographs has been presented. This measurement method is an effective solution for tracking of moving objects, dynamic studies and dimensioning of geometry movements. Nowadays, the use of synchronous photography...
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An analysis of a measurement probe for a high impedance spectroscopy analyzer
PublicationW artykule przedstawiono sondę będącą obwodem wejściowym analizatora do spektroskopii wysokoimpedancyjnej. Sonda umożliwia pomiar impedancji jednym zaciskiem uziemnionej w zakresie od 100ohm do 100Gohm. Sonda umożliwia wydzielenie dwóch sygnałów proporcjonalnych do prądu i napięcia na impedancji mierzonej w szerokim zakresie częstotliwości od 100uHz do 100MHz.Przeprowadzono analizę sondy w której uwzględniono najważniejsze czynniki...
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An analysis of a measurement probe for a high impedance spectroscopy analyzer
PublicationW artykule przedstawiono sondę będącą obwodem wejściowym analizatora do spektroskopii wysokoimpedancyjnej. Sonda umożliwia pomiar impedancji jednym zaciskiem uziemnionej w zakresie od 100ohm do 100Gohm. Sonda umożliwia wydzielenie dwóch sygnałów proporcjonalnych do prądu i napięcia na impedancji mierzonej w szerokim zakresie częstotliwosci od 100uHz do 100MHz.Przeprowadzono analizę sondy w której uwzględniono najważniejsze czynniki...
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A Stand for Measurement and Prediction of Scattering Properties of Diffusers
PublicationIn this paper we present a set of solutions which may be used for prototyping and simulation of acoustic scattering devices. A system proposed is capable of measuring sound field. Also a way to use an open source solution for simulation of scattering phenomena occurring in proximity of acoustic diffusers is shown. The result of our work are measurement procedure and a prototype of the simulation script based on FEniCS - an open source...
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Velocity measurement using the fdoa method in ground-based radio navigation system
PublicationVelocity is one of the main navigation parameters of the moving objects. However some systems of position estimation using radio wave measurements cannot provide velocity data due to limitation of their performance. In this paper a velocity measurement method for DS-CDMA radio navigation system is proposed, which doesn’t require full synchronization of reference stations carrier frequencies. The article presents basics of FDOA...
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Performance of a hybrid microjet – microchannel cooling module
PublicationThe paper presents the experimental investigation of a microjet- microchannel cooling module. In which microjets of water are impinging into the microchannels and forming a liquid film on the impingement surface. Applied technology takes benefits from two very attractive heat removal techniques. When lminar jets are impinging on the surface have a very high kinetic energy at the stagnation point, also in microchannels boundary...
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Performance evaluation of Unified Memory with prefetching and oversubscription for selected parallel CUDA applications on NVIDIA Pascal and Volta GPUs
PublicationThe paper presents assessment of Unified Memory performance with data prefetching and memory oversubscription. Several versions of code are used with: standard memory management, standard Unified Memory and optimized Unified Memory with programmer-assisted data prefetching. Evaluation of execution times is provided for four applications: Sobel and image rotation filters, stream image processing and computational fluid dynamic simulation,...
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Domestic ORC micro-CHP combined with a commercial gas boiler
PublicationThe chapter presents the results of experimental studies conducted during the launch of the first in Poland demonstration prototype of the micro ORC coupled to a domestic gas boiler. The accomplished studies indicated the possibility for the ORC module to work with such boiler (autonomous source of heat) with a prototype single-stage axial micro turbine as the expansion machine. Confirmation of that fact has been delineated in...
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Performance of the very high-temperature heat pump with low GWP working fluids
PublicationTraditional heat pumps are a very attractive pro-ecological solutions for a number of applications, including providing of heating or heat recovery from industrial processes. The application range of heat pumps could be greatly enlarged when the operating temperature would be increased to 130-150°C and/or the temperature lift can be increased to 50-100 K. In the paper, the very high temperature vapour-compressor based single stage...
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Experimental research on marine oil-lubricated stern tube bearing
PublicationBearings of propeller shafts are very crucial elements of the propulsion system of each of the ships. The safety of shipping depends on their durability and reliability. The new legal restrictions mean that today we are looking for environmentally friendly solutions. That is why water-lubricated bearings are becoming more and more popular. So, will oil-lubricated shaft bearings belong to the past? The bearing with a white metal...
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Study on the Influence of an Axial Distance Between Rotors on a Performance of a Small Counter-Rotating Wind Turbine
PublicationIn this paper, results of the investigation on the performance of a small counter-rotating wind turbinehas been presented. Computational Fluid Dynamics methodshave been used forwind turbine simulations. Rotors representation were introduced into computational domain by means of Actuator Line Model. Influence of an axial distance of CRWTrotorshas been investigated. In all studied configurations rotors were counter-rotating...
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Numerical simulation of natural convection of Glycol-Al2O3 nanofluids from a horizontal cylinder
PublicationThis paper deals with natural convection around a circular cylinder with constant heat flux in a cavity using computational fluid dynamics. As fluids ethylene glycol and a mixture of ethylene glycol with Al2O3 nanoparticles (mass concentrations of nanoparticles: 0.1% and 1%) are chosen. Rayleigh number ranges from 3104 to 3105. The nanofluids are modeled with single-phase approach. For the investigated range of nanoparticle concentration, the...
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Effects of Laser Remelting at Cryogenic Conditions on Microstructure and Wear Resistance of the Ti6Al4V Alloy Applied in Medicine
PublicationThe titanium and its alloys can be subjected to surface treatment, including laser treatment. In this work a new laser treatment at cryogenic conditions of Ti6Al4V alloy has been described. The work has been aimed at establishing whether such surface treatment could be suitable for implants working under wear in biological corrosive environment. The remelting has been made with the use of CO2 continuous work laser at laser power...
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Symulacja komputerowa obiektu dynamicznego na przykładzie biogazowni
PublicationW artykule przedstawiono symulator czasu rzeczywistego biogazowni rolniczej. Przedstawiony symulator obejmuje obiegi biomasy, biogazu a także obieg grzewczy wraz z systemem sterowania urządzeniami układów biogazowni oraz wizualizacją procesów. Badania koncentrowały się na wykonaniu symulatora, który odzwierciedla istniejące instalacje. Oprogramowaniem służącym do symulacji jest system CFD (Computational Fluid Dynamics) dający...
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Stirling engines powered by renewable energy sources
PublicationStirling engine is a device that produces mechanical energy using heat from any source of energy, without the need of combustion of any fuel inside the device. Renewable energy sources, which are mostly low-temperature energy sources, can be used to produce mechanical and electrical energy in Stirling engines. The paper presents an overview of the existing prototype Stirling engines designed for using of low-temperature energy...
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Three-Dimensional Printing of Bone Models
PublicationThe trabecular bone occurs, for example, in the femoral heads. Understanding the phenomenon of bone tissue degeneration can be the basis for the possibility of looking for alternative methods of surgical treatment of bone loss. The paper presents the results of the trabecular bone model, which was produced in additive manufacturing method with fused filament fabrication technology. The verification of the mechanical behavior of...
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FLUID DYNAMICS RESEARCH
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Selected aspects of two-phase flow studies using different visualization techniques in minichannels
PublicationThe subject of the study is to present the possibility of the use of visualization techniques in the researches on two-phase flows, carried out by the authors for many years. These works included as follows: heat transfer during the flow boiling, boiling crises and condensation in flow. The issue of the heat transfer intensification during the flow boiling through the channels of small diameters was analyzed. All this work focused...
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Electrochemical sensor for measurement of volatile organic compounds employing square wave perturbation voltage
PublicationThe paper presents the results of investigation on a prototype sensor for measurement of benzaldehyde in air. Sensitivity and limit of quantification of the sensor were determined for different internal electrolyte using the square wave voltammetry (SWV) as a detection technique. The working and counter electrodes were made of platinum. Ionic liquids 1-hexyl, 3-methylimidazolium chloride,1-hexyl, 3-methylimidazolium bis (trifluoromethanesulfonyl)...
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Measurement of Latency in the Android Audio Path
PublicationThis paper provides a description of experimental investigations concerning comparison between the audio path characteristics of various Android versions. First, information about the changes in each system version in the context of latency caused by them is presented. Then, a measurement procedure employing available applications to measure latency is described comparing to results contained in the Internet. Finally, a comparison...
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Verification of baffle factor for straight pipe flow
PublicationDuring the water disinfection devices designing, it is often assumed that the baffle factor for a straight pipe reactors is equal to one. It would be possible only for the plug flow, which is a simplified model of the flow and does not appear in real situations. The paper contains an equation which enables calculation of the real value of the baffle factor for the pipe flow.
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Multiaspect measurement analysis of breaking energy recovery
PublicationNowadays the issue of electric energy saving in public transport is becoming a key area of interest, which is connected both with a growth of environmental awareness in the society and an increase in the prices of fuel and electricity. That is why the reduction of energy consumption by increasing electrified urban transport, such as trams, trolleybuses, light rail and underground is becoming an increasingly important issue. Energy...
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Risk Analysis by a Probabilistic Model of the Measurement Process
PublicationThe aim of the article is presentation of the testing methodology and results of examination the probabilistic model of the measurement process. The case study concerns the determination of the risk of an incorrect decision in the assessment of the compliance of products by measurement. Measurand is characterized by the generalized Rayleigh distribution. The model of the meas-urement process was tested in parallel mode by six risk...
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FIBRE-OPTIC SENSOR FOR SIMULTANEOUS MEASUREMENT OF THICKNESSAND REFRACTIVE INDEX OF LIQUID LAYERS
PublicationIn this paper, we present a fibre-optic sensor for simultaneous measurement of refractive index and thickness of liquid layers. We designed an experimental low-coherence setup with two broadband light sources and an extrinsic fibre-optic Fabry–Pérot interferometer acting as the sensing head. We examined how the refractive index of a liquid film and its thickness affect spectrum at the output of a fibre-optic interferometer. We...
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Experimental investigations on adiabatic frictional pressure drops of R134a during flow in 5mm diameter channel
PublicationThe article presents detailed two-phase adiabatic pressure drops data for refrigerant R134a at a saturation pressure of 5.5 bar corresponding to the saturation temperature of 19.4 °C. Study cases have been set for a mass flux varying from 100 to 500 kg/m2 s. The frictional pressure drop was characterized for the refrigerant R134a, for vapor qualities ranging from 0 to 1. Long-time thermal stability of test facility allowed to gather...
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Electrohydrodynamic secondary flow in the electrostatic precipitator with spiked electrodes
PublicationIn this work, the results of electrohydrodynamic (EHD) secondary flow measurements in an electrostatic precipitator (ESP) with one-sidedspike electrodes are presented. The EHD secondary flow was measured for one-sided spike electrodes with the spike tips directed either upstream or downstream the primary flow. The results showed different flow patterns for different spike tips direction in respect to the primary flow direction....
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The Maslov index and the spectral flow—revisited
PublicationWe give an elementary proof of a celebrated theorem of Cappell, Lee and Miller which relates the Maslov index of a pair of paths of Lagrangian subspaces to the spectral flow of an associated path of self-adjoint first-order operators. We particularly pay attention to the continuity of the latter path of operators, where we consider the gap-metric on the set of all closed operators on a Hilbert space. Finally, we obtain from Cappell,...
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EVALUATION OF LIQUID-GAS FLOW IN PIPELINE USING GAMMA-RAY ABSORPTION TECHNIQUE AND ADVANCED SIGNAL PROCESSING
PublicationLiquid-gas flows in pipelines appear in many industrial processes, e.g. in the nuclear, mining, and oil industry. The gamma-absorption technique is one of the methods that can be successfully applied to study such flows. This paper presents the use of thegamma-absorption method to determine the water-air flow parameters in a horizontal pipeline. Three flow types were studied in this work: plug, transitional plug-bubble,...
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Laser reflectance interferometry system with a 405 nm laser diode for in-situ measurement of CVD diamond thickness
PublicationIn situ monitoring of the thickness of thin diamond films during technological processes is important because it allows better control of deposition time and deeper understanding of deposition kinetics. One of the widely used techniques is laser reflectance interferometry (LRI) which enables non-contact measurement during CVD deposition. The authors have built a novel LRI system with a 405 nm laser diode which achieves better...
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Impact of adverse winter weather on traffic flow
PublicationThe paper aims to analyse the impact of adverse weather in winter on traffic flow using data from a dual carriageway section of an express road located in Gdansk. For the purposes of the analysis, traffic and meteorological data were collected for a period of 15 months in 2014-2015 and aggregated to 5 minutes intervals. The impact of winter weather conditions on traffic flow was assessed by comparing aggregated traffic stream parameters...