Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "hydrodynamic force" wg kryterium: Temat

  Lista filtrów
Wyrównaj
Wyświetlanie 1-10 z 16
Tytuł:
Effects of water intake layout along the wharf shoreline on ships
Autorzy:
Kong, Xian-wei
Ding, Lei
Liu, Hai-cheng
Qu, Jing
Li, Xiao-song
Powiązania:
https://bibliotekanauki.pl/articles/258971.pdf
Data publikacji:
2019
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
water intake
physical model
numerical model
lateral flow
hydrodynamic force
Opis:
The construction of a water intake along the wharf shoreline can realise the intensive and comprehensive utilisation of the shoreline. However, since the water intake will increase the lateral flow at the wharf and also the hydrodynamic forces on ships, it will bring risks to ships mooring and leaving. The effects of the water intake on ships are studied using a physical model, numerical model and standard formulas. The results show that it leads to an increase of the hydrodynamic forces acting on the ship when the standard formulas are used to calculate the forces without considering the water level difference between the two sides of the ship. The results of the physical model are closer to the real situation. Measures that can effectively reduce the influence of the water intake on ships are proposed by increasing the distance between the wharf front and the front of the water intake as well as the depth of the water inlet windows.
Źródło:
Polish Maritime Research; 2019, 4; 165-171
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cross-waves and pulsating flows in the side-channel spillway - an experimental approach
Autorzy:
Azmeri, Azmeri
Ummah, Chairatun
Jemi, Faris Zahran
Faudli, Imam
Nasaiy, Qurratul 'Aini Benti
Powiązania:
https://bibliotekanauki.pl/articles/2203528.pdf
Data publikacji:
2023
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
cross-waves
hydrodynamic force
physical model
pulsating flow
side-channel spillway
Opis:
Potentially hazardous side-channels of complex geometry need to be investigated using detailed hydraulic physical models. This study aims to analyse the cross-waves pattern and pulsating flow using a side-channel spillway physical model. This study compares the cross-waves pattern were measured using an experimental installation set to generate cross-waves on the surface (original series) with another structure that did not produce cross-waves (modified series). The results showed that the geometry of the left wall caused instability in flow patterns and secondary flows. The starting point of Q2 discharge was detected by minor turbulence on the water surface near the left wall at a water depth of 3.3 m at the starting point of the wall, but with no overtopping. Cross-waves formed downstream at the right wall crosswise, lower than at the left wall. The height of the cross-wave increased substantially from Q100 to Q1000 discharges leading to overtoppings near the left wall at a water depths of 4.2 and 5.0 m at the starting point of the wall, and near the right wall at a water depths of 3.8 and 4.0 m at the upstream point of the wall. The modifications provided optimal hydraulic conditions, i.e. elimination of cross-waves and non-uniform flows. The Vedernikov and Montouri numbers showed that both original and modified series did not enter the area where the pulsating flow occurred. This indicated that both series were free from the pulsating flow.
Źródło:
Journal of Water and Land Development; 2023, 56; 51--57
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Calculating the second-order hydrodynamic force on fixed and floating tandem cylinders
Autorzy:
Motallebi, Mohammad
Ghafari, Hamidreza
Ghassemi, Hassan
Shokouhian, Mehdi
Powiązania:
https://bibliotekanauki.pl/articles/135350.pdf
Data publikacji:
2020
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
fixed cylinder
floating cylinder
second order hydrodynamic force
diffracted wave
potential theory
Opis:
In this paper, the second-order hydrodynamic force on fixed and floating tandem cylinders has been calculated and different parameters have been taken into consideration. An incident wave is diffracted by the fixed cylinder, and as a result low-frequency waves radiate toward the floating cylinder and cause low-frequency second-order hydrodynamic forces to act on the surface of the floating cylinder. The interactions between the fixed and floating cylinders have been investigated by changing the distance between them, as well as the draft and radius of the floating cylinder. By employing perturbation series analysis over the wetted surface, the second-order wave excitation force has been calculated. The maximum force applied on the floating cylinder becomes non-dimensional when considering it with and without the fixed cylinder. The results showed the effect that the existence of the fixed cylinder had on the increase in the second-order forces is quite evident where, for a significant parameter of the floating cylinder, the force in the heave direction was enhanced by up to 1.55 times.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2020, 62 (134); 108-115
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical research of the chip removal process in milling of the closed profile slots
Autorzy:
Gnytko, O.
Kuznetsova, A.
Powiązania:
https://bibliotekanauki.pl/articles/2201130.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
closed slots
milling
chip removal
mathematical models
pneumatic hydrodynamic force
zamknięte szczeliny
frezowanie
usuwanie wiórów
modele matematyczne
pneumatyczna siła hydrodynamiczna
Opis:
Purpose: The chip removal from the cutting zone of closed slots (T-shaped, "dovetail", etc.) is relevant since the repeated cutting of the chip with the blades of the tool teeth leads to a decrease in the resource of the cutting tool and processing accuracy. However, theoretical studies of the processes of filling, accumulation, and movement of the chip have not been considered. The purpose of the research is to develop the theoretical foundations of the chip filling and removing processes from profile slots using pneumatic hydrodynamic action of pressure jets of cooling liquid. Design/methodology/approach: Several stages of the analysed process are considered, namely the separation and filling of the space between the cutter teeth with the chip, filling the machined slot with the chip, removing the chip element from the space between the cutter teeth, moving the chip element along the machined slot, moving the chip array along the machined slot, pneumatic hydrodynamic impact. Findings: The complex of mathematical models have been developed to describe the functioning of the chip removal system during the milling of the closed profile slots in this research. The set of the developed models makes it possible to determine the required values of the design and operating parameters of devices that ensure the chip removal from the cutting zone as a result of the use of inertial forces and the application of additional compulsory forces. Research limitations/implications: Theoretical studies were applied for T-shaped slots for milling cutters with diameters from 12.5 mm to 95 mm made of high-speed steel and carbide inserts during steels and cast irons processing. The use of pneumatic hydrodynamic action is limited by the diameters of the nozzle hole from 0.5 mm to 3 mm. Practical implications: The practical significance of the research lies in the ability to control the process of timely chip removal from the cutting zone and to prevent the repeated ingress of the chip under the milling cutter blade. This is achieved by a set of mathematical models that simulate the chip removal process. Research can be applied in production in slots milling, using a liquid not only to cool the cutting zone but also to remove the chip in a timely manner. Originality/value: Theoretical studies previously not carried out for closed profile slots are presented in the research.
Źródło:
Archives of Materials Science and Engineering; 2022, 113, 2; 69--76
1897-2764
Pojawia się w:
Archives of Materials Science and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Power spectrum analysis for determination of the number of Vertical Axis Wind Turbine blades
Autorzy:
Anweiler, S.
Fedak, W.
Gancarski, W.
Ulbrich, R.
Powiązania:
https://bibliotekanauki.pl/articles/95342.pdf
Data publikacji:
2017
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
renewable energy sources
wind turbine
VAWT
power spectrum
hydrodynamic force
odnawialne źródła energii
turbina wiatrowa
turbiny wiatrowe o osi pionowej
widmo mocy
Opis:
Technology of wind exploitation has been applied widely all over the world and has already reached the level in which manufacturers want to maximize the yield with the minimum investment outlays. The main objective of this paper is the determination of the optimal number of blades in the Cup-Bladed Vertical Axis Wind Turbine. Optimizing the size of the Vertical Axis Wind Turbine allow the reduction of costs and increase the output. The target is the maximum power of the rotor. The optimum number of Vertical Axis Wind Turbine blades evaluation is based on analysis of a single blade simulation and its superposition for the whole rotor. The simulation of working blade was done in MatLab environment. Power spectrum graphs were prepared and compared throughout superposition of individual blades in the Vertical Axis Wind Turbine rotor. Some wind tunnel measurements of the hydrodynamic force according to pitch angle of the blade are also shown. The major result of this research is the Vertical Axis Wind Turbine kmax ratiopower characteristic. On the basis of the analysis of the power spectra, optimum number of the blades was specified for the analysed rotor. Power spectrum analysis of wind turbine enabled the specification of the optimal number of blades, and can be used regarding investment outlays and power output of the Vertical Axis Wind Turbine.
Źródło:
Journal of Mechanical and Energy Engineering; 2017, 1, 2; 153-161
2544-0780
2544-1671
Pojawia się w:
Journal of Mechanical and Energy Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Examination of hydraulic amplifiers in the aspect of lifetime prediction
Autorzy:
Jastrzębski, G.
Ułanowicz, L.
Powiązania:
https://bibliotekanauki.pl/articles/244003.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
hydraulic amplifier
distributing slider
hydrodynamic radial force
insensitivity (dead) zone of a hydraulic amplifier
durability (lifetime)
Opis:
The paper presents the lifetime analysis for a hydraulic amplifier and considers two types of the flow distributing devices, i.e. a linear distributings lider and a rotarys lider. Description of essential properties associated with operation of distributing devices in hydraulic amplifiers is included with particular attention to analysis of processes that affect wear and tear of hydraulic amplifiers and influence quality of their operation. In that context a set of parameters that determine operation quality of hydraulic amplifiers was found out where mutual independence of the parameters, their unambiguousness and measurability served as the criteria for selection there of two methods of analysis were used that took account for the foregoing assumption, i.e. the method of maximum informative capacity of the parameter and the method that assumes maximum alteration of the technical condition due to execution of the test. The completed examinations made it possible to find out characteristic curves for hydraulic amplifiers with a linear distributing slider as well as with a rotary slider with regard to their accumulated operation time. Further predictions of the hydraulic amplifier lifetime take advantage of the assumption that the deterioration effect of functional parameters attributable to hydraulic amplifiers is represented by a series of time-related values (y1,y2.....yn)i.e. a set of discrete observations {y1=ksi(teta)} associated with an unsteady stochastic process ksi(teta). The relationships how functional parameters o f a hydraulic amplifier vary in pace with its operation time t are described by means of the Gaussian distribution with the assumption that the course of a functional parameter deterioration corresponds to its aggregated characteristic curve that represents resistance of a distributing device embedded into a hydraulic amplifier to wear and tear processes. Wear of crucial parts within a hydraulic amplifier is measured in terms how functional parameters of that part associated with its accuracy, sensitivity and switching speed are getting worse and worse as time goes by.
Źródło:
Journal of KONES; 2010, 17, 3; 165-172
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The friction force and friction coefficient in the journal sliding bearing ferrofluid lubricated with different concentrations of magnetic particles
Autorzy:
Frycz, M.
Miszczak, A.
Powiązania:
https://bibliotekanauki.pl/articles/247265.pdf
Data publikacji:
2011
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
hydrodynamic pressure
capacity
friction force
friction coefficient
ferrofluid
numeric calculation
Opis:
There is an important operational parameter in the case of sliding bearings are friction forces and coefficient of friction. It depends on how much proportions of heat in the gap of the oil film from the value of the friction force. Ferrofluid lubricated sliding bearings have specific structure and are suitable only for use in specific cases. We may use them in the absence of gravity, vacuum, or in case of strong magnetic fields or radioactive. Maintenance of lubricant in the oil-gap as well as the viscosity change occurs through controlling of the external magnetic field. Change of the value of viscosity and mass forces (magnetic forces) in the equation of momentum depends on the concentration of magnetic particles and the intensity of external magnetic field. The aim of this paper is to present the influence of concentration of magnetic particles on the friction force value and coefficient of friction. The numerical calculations of friction forces and friction coefficient have been performed before setting the hydrodynamic pressure and a lift force from the Reynolds-type equation. Reynolds-type equation has been derived from basic equations, ie equations of momentum and equations of stream's continuity. There have been also used Maxwell's equations for the ferrofluid in the case of stationary magnetic field's existence. It has been assumed stationary and laminar flow of lubricant liquid and the isothermal model for lubrication of slide bearings. As the constitutive equation has been used Rivlin-Ericksen one. The cylindrical journal bearing of finite length with the smooth sleeve of whole angle of a belt has been taken into consideration. In a thin layer of oil film has been assumed constancy of the oil density with temperature changes and the independence of the oil's thermal conductivity coefficient from thermal changes. The viscosity of the oil depends mainly on the magnetic field.
Źródło:
Journal of KONES; 2011, 18, 4; 113-120
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Carrying capacity and friction forces in a transverse journal bearing, lubricated with non-Newtonian oil
Autorzy:
Miszczak, A.
Sikora, G.
Powiązania:
https://bibliotekanauki.pl/articles/243066.pdf
Data publikacji:
2017
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
slide journal bearing
hydrodynamic pressure
load carrying capacity
friction force
non-Newtonian oil
Opis:
In this article, the authors present the results of numerical calculations. Calculations concern dimensionless carrying capacity and friction forces in a transverse journal bearing, lubricated by the oil of non-Newtonian properties. For analytical-numerical considerations a model of apparent viscosity changes based on exploitation time, pressure, temperature, shear rate was assumed The non-Newtonian properties of lubricating oil were characterized by increasing viscosity with increasing shear rate and described as an additional part in the constitutive equationβ3·tr(A1 2)A1. Analytical-numerical calculations were performed for smooth, non-porous plain bearing with full angle of wrap. Non-isothermal, laminar and fixed flow of lubricant in the lubrication gap of the journal bearing was assumed. Numerical calculations of hydrodynamic pressure distribution were made for Reynolds boundary conditions. The finite difference method was used to determine the Reynolds equation and the successive approximation method by taking into account the influence of pressure, temperature and non-Newtonian properties on the change of apparent viscosity. The results of the calculations are presented in the form of graphs and tables illustrating the influence of relative eccentricity and pressure, temperature and non-Newtonian properties on changes in the dimensionless load and friction force. Analysis of the obtained results illustrates the high-pressure effect on the increase of the carrying capacity and friction force for high relative eccentricities. A similar situation is by considering the non-Newtonian properties.
Źródło:
Journal of KONES; 2017, 24, 3; 203-210
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of hydrodynamic power losses in a gearing
Autorzy:
Stavytskyi, Valerii
Bashta, Oleksandr
Nosko, Pavlo
Tsybrii, Yurii
Powiązania:
https://bibliotekanauki.pl/articles/2106187.pdf
Data publikacji:
2022
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
hydrodynamic power losses
gearing
tooth space
high speed gears
Coriolis force
mathematical model
Opis:
Despite the relatively numerous experimental studies, there are few published works on the topic of development of mathemati-cal models that describe the hydrodynamic processes in gears. There is no generic analytical model that integrates all types of losses. The purpose of this work is to develop a modern generalised methodology for calculating the hydrodynamic power losses of high-speed gears. For each gear, partially or fully immersed into an oil bath, the power spent to overcome the hydromechanical resistance can be represented as the sum of the following: the Coriolis force moment arising from the radial movement of the oil in the tooth spaces of the rotating gear, the viscous friction forces moment on the periphery of the gear addendums in the oil bath and the viscous friction forces moment at the face of the gear in the oil bath. The hydrodynamic power losses due to the Coriolis force action, viscosity friction losses at the periphery of the gear and the viscosity friction at the face of the gear (both turbulent and laminar modes) were observed separately. From the mathematical simulation of the rotation processes when the gear is immersed into the oil bath, an analytical dependence was obtained. It allows predicting the influence of the geometrical parameters of the gearing on the hydrodynamic power losses. Analysis of the calculation results of the power losses due to the action of hydraulic resistance forces and results from experimental studies is provided for several gears with different hydromechanical parameters. The proposed method of calculating power loss due to hydromechanical resistance of the oil bath to the rotation of the gear gave results that were close to the experimental data. Acceptable coincidence of theoretical and experimental results allows recommending the received analytical dependencies for practical calculations of high-speed gears.
Źródło:
Acta Mechanica et Automatica; 2022, 16, 1; 1--7
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improvement of tribotechnical characreristics of the main engines pairings at electrochemical-mechanical running-in
Uluchshenie tribotekhnicheskikh kharacteristik osnovnykh soprazhenijj dvigatelja ehlektrokhimiko-mekhanicheskojj prirabotkojj
Autorzy:
Zamota, T.
Aulin, V.
Powiązania:
https://bibliotekanauki.pl/articles/793073.pdf
Data publikacji:
2013
Wydawca:
Komisja Motoryzacji i Energetyki Rolnictwa
Tematy:
electrochemical-mechanical running
engine
hydrodynamic lubrication
friction surface
mechanical property
physical property
friction force
Źródło:
Teka Komisji Motoryzacji i Energetyki Rolnictwa; 2013, 13, 3
1641-7739
Pojawia się w:
Teka Komisji Motoryzacji i Energetyki Rolnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-10 z 16

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies