Temat: hydromechanics - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Waterjet propulsion of small-draught inland waterways ships
Autorzy:: Domachowski, Z.
Próchnicki, W.
Tematy:: ship propulsion
hydromechanics; Pokaż więcej
Data publikacji:: 2006
Powiązania:: https://bibliotekanauki.pl/articles/260461.pdf Link otwiera się w nowym oknie
Źródło:: Polish Maritime Research; 2006, S 2; 66-71
1233-2585
Pojawia się w:: Polish Maritime Research
Opis:: This paper presents some aspects of ship waterjet propulsion. Advantages and limitations of its applicability are discussed. Also, possible use of waterjet propeller to move a small-draught inland waterways ship, is considered .
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: A proposal of ship gas-turbine driven waterjet propulsion - preliminary considerations
Autorzy:: Próchnicki, W.
Tematy:: ship propulsion
hydromechanics
waterjet; Pokaż więcej
Data publikacji:: 2004
Powiązania:: https://bibliotekanauki.pl/articles/962800.pdf Link otwiera się w nowym oknie
Źródło:: Polish Maritime Research; 2004, S 1; 79-82
1233-2585
Pojawia się w:: Polish Maritime Research
Opis:: In the paper are presented preliminary considerations concerning the efficiency of waterjet ship propulsion system, as well as the calculation of main dimensions of waterjet channel. The friction and momentum losses of the flow channel have been roughly estimated by using Fliegner s equations. An important conclusion is confirmed that the summary losses are inversely proportional to square of ship velocity (~1/u2). On the other hand the ship propulsion power is directly proportional to third power of ship velocity (~u3). Therefore to minimize ship s hull resistance, hulls of water jet-driven ships ought to be of a great slenderness - e.g. L/B = 15, stabilized by sponsons, or of semi-swath hydrofoil-supported construction.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Experimental Determination of Limit Adhesive Shear Stress between Solid Wall and Liquid
Autorzy:: Sawicki, J. M.
Tematy:: hydromechanics
slip boundary conditions
adhesion; Pokaż więcej
Data publikacji:: 2014
Powiązania:: https://bibliotekanauki.pl/articles/241430.pdf Link otwiera się w nowym oknie
Źródło:: Archives of Hydro-Engineering and Environmental Mechanics; 2014, 61, 3-4; 175--181
1231-3726
Pojawia się w:: Archives of Hydro-Engineering and Environmental Mechanics
Opis:: The slip boundary condition can be a very useful relation when some specific problems of hydromechanics are considered. According to the classical form of this condition, the slip of a fluid with respect to the solid wall should occur even at a very low velocity of motion. However, both theoretical analysis and certain empirical data suggest that there must be a limit value of the wall shear stress, below which the slip does not occur. According to the simplified balance of adhesive and gravitational forces, a simple experimental method for determining this stress has been proposed and applied in this paper.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Evaluation of effectiveness of waterjet propulsor for a small underwater vehicle
Autorzy:: Rowinski, Lech
Kaczmarczyk, Maciej
Tematy:: ship propulsion
hydromechanics
waterjet
underwater vehicle; Pokaż więcej
Data publikacji:: 2021
Powiązania:: https://bibliotekanauki.pl/articles/2033211.pdf Link otwiera się w nowym oknie
Źródło:: Polish Maritime Research; 2021, 4; 30-41
1233-2585
Pojawia się w:: Polish Maritime Research
Opis:: The goal of the project described is to replace the existing propulsion system of a small underwater vehicle with a solution less prone to mechanical damage and ensuring a lower risk of the entanglement of fibrous objects suspended in the body of water. Four typical marine screws are utilised in the current design of the vehicle. One possible solution of the problem is the application of waterjet propulsors located inside the body of the vehicle instead. The general conditio of the application of the new solution was to secure at least the same motion control capabilities of the vehicle while the basic capability is its propulsion effectiveness at the required speed. Specific features of the considered waterjet propulsor, when compared with their application in surface vessel propulsion, are the lack of the head losses and the low significance of cavitation issues. One of the difficulties in the considered case is the small diameter of the propulsor in comparison to commercially available waterjet units, which have diameters between 0.1 [m] and 1.0 [m]. There is very little data regarding the design and performance of devices in the 0.02 to 0.05 [m] range. Methods utilised to forecast the performance of the new propulsion system are presented and results compared. These were semi-empirical calculations, numerical calculations and tests of real devices. The algorithm that is based on semi-empirical calculations is of particular interest while it offers possibility quick assessment of performance of a propulsor composed of several well defined components. The results indicate the feasibility of modification of the propulsion system for the considered vehicle if all the existing circumstances are taken into account.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Investigations of influence of screw propeller operation on water flow around stern part of ship hull
Autorzy:: Koronowicz, T.
Krzemianowski, Z.
Tematy:: ship hydromechanics
propeller-induced velocities
Biot-Savart equation; Pokaż więcej
Data publikacji:: 2007
Powiązania:: https://bibliotekanauki.pl/articles/260348.pdf Link otwiera się w nowym oknie
Źródło:: Polish Maritime Research; 2007, 1; 3-8
1233-2585
Pojawia się w:: Polish Maritime Research
Opis:: This paper presents results of measurements of velocity field in before- the - propeller flow in presence of a ship model hull of two configurations, as well as comparative calculations of velocity field on a full-scale ship. Analysis of the research results showed that input data to Biot-Savart formula should be modified in the case of calculations of propeller-induced velocities on ship hull surface.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: The current and future possibilities to adapt the R-JH3 method to ship power prediction practice
Autorzy:: Jarzyna, H.
Tematy:: ship hydromechanics
theory of propellers
ship hull-propeller interaction; Pokaż więcej
Data publikacji:: 2005
Powiązania:: https://bibliotekanauki.pl/articles/259176.pdf Link otwiera się w nowym oknie
Źródło:: Polish Maritime Research; 2005, 1; 3-7
1233-2585
Pojawia się w:: Polish Maritime Research
Opis:: In the paper the current and future possibilities of the R-JH3 method are discussed. The R-JH3 method (presented in detail in [27]) was elaborated for the ship power prediction on the basis of a new definition of the open-water propeller fully equivalent to the behind-the--hullpropeller. The R-JH3 method can be used to determine the mean effective velocity and the mean effective pitch coefficient of the behind propeller. The R-JH3 method may be very useful for scale-effect investigations and scale-effect designation when results of model self-propulsion test have to be transformed to the ship scale.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Matematicheskaja model gidroprivoda blochno-porcionnogo otdelitelja konservirovannykh kormov
Mathematical model of gidroprivoda of block-portion out of the canned forage
Autorzy:: Ivanov, N.
Shargorodskijj, S.
Rutkevich, V.
Tematy:: hydraulic drive
design
automatic control
dynamic process
hydromechanics
mathematical model; Pokaż więcej
Data publikacji:: 2013
Powiązania:: https://bibliotekanauki.pl/articles/76995.pdf Link otwiera się w nowym oknie
Źródło:: Motrol. Motoryzacja i Energetyka Rolnictwa; 2013, 15, 5
1730-8658
Pojawia się w:: Motrol. Motoryzacja i Energetyka Rolnictwa
Opis:: The questions of design of dynamic processes, flowings in the difficult gidro-mechanical subsystem of mechanism for block-portion out loading carte separator of the canned forage are examined. The princip of operation of loading device for block-portion out loading of canned forage out of pit storage is described. The hydraulic drive of mechanism for block-portion out loading carte separator which allows to coordinate work of drive of knife mechanism with his serve is described. The mathematical model of gidroprivoda of separator and results of his research is resulted.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Roll response of ship fitted with passive stabilizing tank
Autorzy:: Balcer, L.
Tematy:: seaworthiness
ship safety
ship hydromechanics
stability of floating units; Pokaż więcej
Data publikacji:: 2004
Powiązania:: https://bibliotekanauki.pl/articles/259377.pdf Link otwiera się w nowym oknie
Źródło:: Polish Maritime Research; 2004, 3; 12-20
1233-2585
Pojawia się w:: Polish Maritime Research
Opis:: Physical and mathematical models of roll motions of a ship equipped with a roll stabiliŹzing tank of working liquid free surface, is presented. Elaboration of the physical model was based on the idea of two mutually coupled mathematical pendulae. On the basis of the physical model, motion equations of the ship with the tank were determined and solŹved. A way of using the achieved solutions is shown, as well as calculation formulae for coefficients of the motion equations, directly related to the main parameters of the ship and tank, are presented. Such form of the coefficients enhances possibility of application of the equations and their solutions in ship design practice. Some examples of the use of the solutions for analysis of stabilizing effectiveness of a designed tank for a given ship, are also attached. Moreover, guideŹlines for correct design of the stabilizing tanks having free surface of liquid, based on the proposed physical model of the ship-tank system, are offered. It is also indicated that on the basis of the presented results it would be possible to search for ways to make operation of the stabilizing tanks in question more effective.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Location of ship rolling axis
Autorzy:: Balcer, L.
Tematy:: ship seaworthiness
ship safety
ship hydromechanics
stability of floating units; Pokaż więcej
Data publikacji:: 2004
Powiązania:: https://bibliotekanauki.pl/articles/259294.pdf Link otwiera się w nowym oknie
Źródło:: Polish Maritime Research; 2004, 1; 3-7
1233-2585
Pojawia się w:: Polish Maritime Research
Opis:: In the paper is presented a definition of ship rolling axis and a method for determination of location of the axis. Location of rolling axis depends not only on ship mass distribution but also on the so-called "added masses" which are equivalents of the hydrodynamic forces acting on ship hull during its motion. It has been assumed that the rolling axis is fixed with respect to ship's hull, and its location is determined with accounting for the added masses accompanying ship rolling, whereas the influence of damping forces is neglected. For a representative group of ships appropriate coefficients of hydrodynamic forces were calculated on the basis of the experimental test results available in the subject-matter literatuŹre. It has been assumed that the rolling axis passes through a common centre of ship's mass and relevant added masses. As a result proposed are simple approximate formulas which make it possible to calculate location of ship rolling axis on the basis of the typical ship data available at the preliminary design stage.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Modern numerical techniques for the ships safety estimation in critical conditions
Autorzy:: Gerigk, M.
Tematy:: design of ships
ships hydromechanics
safety of ships
design of safety; Pokaż więcej
Data publikacji:: 1999
Powiązania:: https://bibliotekanauki.pl/articles/1954534.pdf Link otwiera się w nowym oknie
Źródło:: TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 1999, 3, 2; 201-225
1428-6394
Pojawia się w:: TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Opis:: In this paper a method for a ship safety estimation at the preliminary stage of design is briefly presented. Solving a few hydrostatic and dynamical problems may be taken into account using the method with special regards to the ships safety estimation in critical conditions. The critical conditions may concem the problems of survivability caused due to the cargo and/or ballast shift, waves and wind impact including the ingress of external water into the watertight compartments of a ship. The theoretical and computational models are briefly described. Using the computational model the safety assessment may be done for the initial event and scenario development assumed. Then, either some seakeeping, stability, damage stability or survivability related characteristics should be evaluated for the risk assessment. Both the seakeeping and stability characteristics are treated as the initial conditions for the risk assessment regarding the damage stability and survivability, and it usually follows from the hazard scenario development. The risk assessment is the base for the safety estimation. This is done according to the IMO regulations. The computational model incorporates the modern numerical techniques and is briefly described by introducing the logical structure of design system, logical structure of computational model and a few application methods used. The model enables to estimate the safety combining the influence of the hull form parameters, arrangement of internal spaces, loading condition including both the cargo distribution and permeability and impact of exciting forces. The exciting forces may follow from both the external and internal sources. And they are as follows: waves, wind and cargo and ballast shift.
Dostawca treści:: Biblioteka Nauki

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