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1
Content available Comparative analysis of the theoretical models of ideal propulsor, ideal fluid brake, ideal screw propeller and ideal axial wind turbine
Koronowicz T., Szantyr J. A.
Polish Maritime Research
|
2013
|
nr 2
3--12
EN
The article presents a detailed discussion of the theoretical models of four different fluid dynamic devices: an ideal propulsor, an ideal fluid brake, an ideal screw propeller and an ideal turbine. The four models are presented with all relevant mathematical formulae regarding the forces, the power and the efficiency. It is demonstrated that the application of the model of an ideal optimum fluid brake according to the Betz theorem for determination of the maximum effectiveness coefficient of an axial wind turbine is not correct. In the case of a turbine the inclusion of important rotational flow losses may increase the maximum value of the turbine effectiveness coefficient above the level defined by Betz. Therefore the model of an ideal turbine should be an inversion of the model of an ideal screw propeller. This conclusion is supported by numerical calculations. It may influence the design procedures of wind turbines and may lead to increase in their efficiency.
2
Content available remote Experimental and Numerical Investigation of Small Axial Turbines
Chaja P., Góralczyk A., Koronowicz T.
TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk
|
2010
|
Vol. 14, No 3
307-313
EN
The authors conducted a series of experimental studies using a flow tunnel to determine the hydrodynamic characteristics of small axial turbines. The results obtained were confronted with the results obtained from the authors’ own numerical codes based on vortex methods. This article describes the experiment and the numerical method and also discusses the results obtained.
3
Content available A complete design of tandem co-rotating propellers using the new computer system
Koronowicz T., Krzemianowski Z., Tuszkowska T.
Polish Maritime Research
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2010
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nr 4
17-25
EN
The computer system for the complete design of the tandem co-rotating propellers, presented in this article, has several common blocks and procedures with the computer system for the design of conventional single propellers, presented in detail in Polish Maritime Research No. 1 Vol. 16 (2009). In this article only these blocks and procedures are described, which are different in both systems. The comparative analysis of the designed tandem propeller and a conventional propeller is also included.
4
Content available A complete design of contra-rotating propellers using the new computer system
Koronowicz T., Krzemianowski Z., Tuszkowska T., Szantyr J. A.
Polish Maritime Research
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2010
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nr 1
14-24
EN
The computer system for the complete design of the contra-rotating propellers presented in this article has several common blocks and procedures with the systems for design of single propellers and tandem corotating propellers, presented in detail in the Polish Maritime Research No.1 and No.4 of the Volume 16, 2009. In this article only the blocks and procedures developed specially for the contra-rotating propellers are described. The system is based on the lifting line and lifting surface models and on the Computational Fluid Mechanics methods. The comparative analysis of the contra-rotating propellers and the tandem corotating propellers is included.
5
Content available remote Towards the Design of Low Noise Level Wind Turbines
Chaja P., Koronowicz T.
TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk
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2009
|
Vol. 13, No 4
393-401
EN
According to the authors’ hypothesis generation of high intensity noise is caused by generation of vorticity structures inducing velocities that can be locally higher than the velocity of sound. The localization and magnitude of vorticity concentration can be precisely defined on the basis of a double layer vortex model. Knowing the localization and mechanism of generation of significantly high induced velocities, turbine blades can be shaped in such a way so as to decrease the concentration of vorticity in these zones. According to the hypothesis described in this paper, a modification of turbine blades at the design stage results in their quieter operation for higher loads and wind velocities. The authors base their hypothesis on the experience from design works concerning low noise ship propellers. The following paper focuses on these tasks.
6
Content available A complete design of ship propellers using the new computer system
Koronowicz T., Krzemianowski Z., Tuszkowska T., Szantyr J. A.
Polish Maritime Research
|
2009
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nr 1
29-34
EN
The computer system presented in this article is composed of several program blocks for the complete design of ship propellers. The design calculations are based on a combination of the modified lifting line theory and on the vortex lifting surface theory. The system enables solution of the following design problems: - calculation of the scale effect on the ship wake velocity field, including the influence of the propeller and rudder on this field at the propeller location - maximization of the propulsive efficiency - optimization of the propeller blade geometry on the basis of the compromise between the cavitation and blade strength requirements - optimization of the number of propeller blades and blade geometry on the basis of the acceptable level of induced pressure pulses and unsteady shaft bearing forces - calculation of the blade spindle torque for the controllable pitch propellers. The computer system is equipped with many numerical options for graphical visualization of the input data, including an easy possibility of their correction and control of the intermediate and final results of calculations.
7
Content available A complete design of ducted propellers using the new computer system
Koronowicz T., Krzemianowski Z., Tuszkowska T., Szantyr J. A.
Polish Maritime Research
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2009
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nr 2
34-39
EN
The computer system for the completed design of the ducted ship propellers has some common blocks and procedures with the analogical system for open propellers that has already been presented in detail in the Polish Maritime Research [1]. This article describes only these blocks and procedures which are specific for the design of ducted propellers. These new blocks concern first of all the procedures for the design calculation of ducted propellers and for the analysis of the ducted propeller operation in the non-uniform velocity field behind the ship hull. The comparative analysis of computation results for different types of ducts is also presented.
8
Content available Comparison of CICSAM and HRIC high-resolution schemes for interface capturing
Wacławczyk T., Koronowicz T.
Journal of Theoretical and Applied Mechanics
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2008
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Vol. 46 nr 2
325-345
EN
The paper concerns the modelling of a flow with high density and viscosity ratios using the Volume of Fluid method (VOF). Two high resolution schemes are used for discretization of the nonlinear convective term in the equation for transport of the volume fraction. Properties of the schemes are compared by taking into consideration their ability to capture the interface subjected to strong deformation.We show that diffusive properties of the high-resolution schemes affect the obtained solution. Verification of the schemes is performed in two test cases: rotation of a solid body with a slot and sloshing of water in a rectangular tank.
PL
Tematem niniejeszej pracy jest modelowanie przepływu w układzie płynów o dużym stosunku gęstości i lepkości z dobrze określoną powierzchnią rozdziału: wody i powietrza. Symulacje komputerowe przeprowadzono za pomocą własnego kodu z zaimplementowaną metodą Volume of Fluid (VOF), w której pozycja powierzchni rozdziału zostaje określona poprzez śledzenie rozkładu objętościowego współczynnika wypełnienia w czasie. Dwa schematy o wysokiej rozdzielczości ClCSAM i HRlC służące do dyskretyzacji członu konwekcyjnego w równaniu transportu objętościowego współczynnika wypełnienia zostały porównane w dwóch przypadkach testowych: rotacji ciała ze szczeliną oraz ruchu wody w zbiorniku wywołanego działaniem zewnętrznej siły. Głównym wnioskiem z wykonanych symulacji oraz porównania wyników obliczeń z danymi doświadczalnymi jest fakt zależności otrzymanych wyników od właściwości numerycznych analizowanych schematów, a w szczególności sposobu rekonstrukcji powierzchni rozdziału. W przypadku niejednorodnej mieszaniny płynów oba wspomniane schematy wprowadzają dodatkowe przesunięcie w czasie do historii zmian ciśnienia oraz tłumienie ekstremalnych wartości amplitudy ciśnienia wskazujące na nieprawidłową rekonstrukcję dynamiki mieszaniny. Schemat ClCSAM rekonstruje zachowanie płynów w sposób bardziej zbliżony do danych doświadczalnych w prównaniu ze schematem HRlC. Dowodem na to jest mniejsze przesunięcie w czasie względem danych doświadczlnych oraz mniej wyraźne tłumienie ekstremalnych wartości ciśnienia.
9
Content available remote Remarks on prediction of wave drag using VOF method with interface capturing approach
Wacławczyk T., Koronowicz T.
Archives of Civil and Mechanical Engineering
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2008
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Vol. 8, no 1
7-16
EN
This paper concerns modeling of the free surface flow using Volume of Fluid (VOF) method with interface capturing approach. Equation for transport of the volume fraction is discretized using three high resolution schemes. We show that artificial dependence of the high-resolution scheme on the Courant number and switching to first order upwind differencing scheme introduces numerical diffusion that affects solution. Moreover, dynamic character of the scheme can cause artificial interface deformation influencing final wave profile and thus wave drag prediction. Additionally some results connected with modeling of the flow around free surface piercing body are presented.
PL
W artykule przedstawiono model jednopłynowy stosowany w metodzie VOF oraz przedyskutowano j porównano właściwości trzech schematów o wysokiej rozdzielczości. Zależności schematu o wysokiej rozdzielczości od liczby Couranta, schematy CICSAM [8], HRIC [7], prowadzi do występowania sztucznej dyfuzji w wyniku przełączania do schematu różnicowego pierwszego rzędu tzw. pod-prąd (UDS), zobacz Rysunek 2. Zaproponowana modyfikacja, schemat M-CICSAM, pozwala na uniknięcie tego efektu, zapewniając jednocześnie poprawną rekonstrukcję powierzchni rozdziału. W drugiej części artykułu przedstawiono pierwsze wyniki obliczeń stosując zaproponowany schemat M-CICSAM, w trójwymiarowej przestrzeni obliczeniowej. Wyniki zostały otrzymane za pomocą akademickiego kodu FAS TEST wraz z zaimplementowaną przez autorów metodą VOF ze schematami o wysokiej rozdzielczości (współpraca z TU Darmstadt FNB). Otrzymane wyniki obliczeń porównano z profilami fali otrzymanymi eksperymentalnie [12], otrzymując jakościową zgodność. Dalsze prace będą polegały na uwzględnieniu w obliczeniach modelu turbulencji oraz przeprowadzeniu wyznaczania oporu dla rzeczywistych kadłubów statków.
10
Content available remote A computer system for the complete design of ship propellers
Koronowicz T., Chaja P.
Archives of Civil and Mechanical Engineering
|
2008
|
Vol. 8, no 1
49-59
EN
The integrated computer system presented in this paper is capable of conducting the complete design calculations of ship propellers, including their ana1ysis in the conditions of a real inflow velocity field behind the ship hull.The system enables solution of the following tasks: - calculation of the scale effect on the velocity field in the area of propeller operation, - correction of this velocity field due to the presence of the rudder, - maximization of the propeller efficiency, - optimization of the propeller blade geometry on the basis of the cavitation and strength requirements, ź optimization of the propeller number of blades and of the blade geometry on the basis of the level or induced pressure pulses and unsteady bearing forces. The computer system contains numerous options for visualization or the input data and the results of calculations.
PL
Zintegrowany system komputerowy przedstawiony w referacie pozwala na przeprowadzenie kompleksowych obliczeń projektowych śrub okrętowych połączonych z analizą ich pracy w rzeczywistym polu prędkości za kadłubem statku. System umożliwia rozwiązanie następujących zadań: . określenie wpływu efektu skali na pole prędkości w miejscu pracy śruby, . skorygowanie tego pola ze względu na wpływ steru, . maksymalizację sprawności śruby, . optymalizację geometrii skrzydła śruby na podstawie wymagań kawitacyjnych i wytrzymałościowych, . optymalizację liczby skrzydeł śruby i ich geometrii na podstawie poziomu indukowanych pulsacji ciśnienia i zmiennych sił łożyskowych. Opisany system komputerowy posiada wiele możliwości wizualizacji danych wejściowych i wyników obliczeń.
11
Content available Investigations of influence of screw propeller operation on water flow around stern part of ship hull
Koronowicz T., Krzemianowski Z.
Polish Maritime Research
|
2007
|
nr 1
3-8
EN
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.
12
Modelling of the free surface flow with high resolution schemes
Wacławczyk T., Koronowicz T.
Inżynieria Chemiczna i Procesowa
|
2006
|
T. 27, z. 3/1
783-802
EN
The paper concerns modelling of the free surface flow with the volume of fluid (VOF) method. The original contribution of this work is a detailed comparison of two high-resolution schemes, taking into consideration their ability to capture the interface subjected to strong deformation. Verification and validation of the schemes is performed in three test cases: advection of the bubble in a uniform velocity field, convection of the bubble including effects of surface tension and breaking of the water wave in the gravitational field.
PL
Poniższa praca dotyczy modelowania przepływów ze swobodną powierzchnią metodą Volume of Fluid (VOF). Oryginalnym wkładem jest szczegółowe porównanie dwóch schematów o wysokiej rozdzielczości ze względu na ich właściwości podczas rekonstrukcji powierzchni rozdziału. Schematy zweryfikowano w trzech przypadkach testowych: swobodnego unoszenia pęcherzyka w jednorodnym polu prędkości, konwekcji pęcherzyka z uwzględnieniem efektów napięcia powierzchniowego oraz załamania fali w polu grawitacyjnym.
13
Content available remote Hydroacoustic activity of the ship propeller operation
Szantyr J.A, Koronowicz T.
Archives of Acoustics
|
2006
|
Vol. 31, No. 4
481-487
EN
The paper presents ship propellers as the source of a variable pressure field in water. The frequency spectrum of this field covers the entire audible range and beyond this range. This pressure field is generated by several physical mechanisms: the rotating hydrodynamic loading of the blades, the displacement effect of the rotating blades, the boundary layer effect, and, first of all, various forms of cavitation. The relative importance of these mechanisms is analysed and the methods of the theoretical prediction of the propeller generated variable pressure field are briefly presented. The results of the prediction are compared with experimental data.
14
Modeling of the flow in systems of immiscible fluids using volume of fluid method with CICSAM scheme
Wacławczyk T., Koronowicz T.
Turbulence : international journal
|
2005
|
Vol. 11
267-276
EN
The paper concerns modeling of the flow in a system of viscous, incompressible and immiscible fluids using Volume of Fluid (VOF) method. The main difficulty in this approach is proper solution of the transport equation for characteristic function, which value indicates volume fraction of the fluid in control volume. To discretise transport equation for characteristic function, CICSAM (Compressive Interface Capturing Scheme for Arbitrary Meshes, cf. [1]) was employed. Solution of the transport equation for the characteristic function - volume fraction - was coupled with home-written second-order Navier-Stokes solver Caffa3d. Three test cases were carried out to show that aforementioned approach can be used to model flow in a systems of immiscible fluids.
15
Content available remote A computer method for prediction of the velocity field behind a full-scale ship hull
Koronowicz T., Tuszkowska T., Wacławczyk T.
Polish Maritime Research
|
2003
|
nr 1
3-9
EN
One of the most important problems in the ship propulsion prognosing is determination of the full-scale velocity field within the propeller operation area behind the ship hull. Numerical calculation results of such velocity field, obtained by means of the own computer software PANSHIP-2 (the "numerical model basin") are presented in this paper. Selected examples illustrate the influence of propeller operation on the effective field. Also, the scale effect of the nominal flow field is discussed.
16
Content available remote Rationality of solving 3D circulation problems exclusively with the use of the Navier-Stokes equation (Reynolds equation)
Koronowicz T.
TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk
|
2002
|
Vol. 6, No 1
217-224
EN
The paper presents problems connected with solving 3D circulation problems. The existence of vortex singularities in the flow behind a body is a characteristic feature of such problems. The vortices influence the velocity and pressure fields in the vicinity of a body. A proposition of rational merging the methods based on the N-S equation together with vortex methods (based on the vorticity equation) is discussed. Such a connection enables accurate and efficient determination of vortex singularities in the flow behind a body.
17
Content available remote Badania eksperymentalne opływu wierzchołków płatów na tle obliczeń numerycznych
Koronowicz T., Tuszkowska T.
Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka
|
2000
|
nr 117, vol. 1
307-314
PL
W pracy zaprezentowano wyniki badań teoretycznych i eksperymentalnych związanych z opływem wierzchołków skrzydeł, począwszy od pierwszych modeli wirowych skrzydeł Żukowskiego, a kończąc na dwupowłokowym modelu powierzchni nośnej. Zaprezentowano tu najnowsze wyniki badań modelowych kawitacji wirowej na tle obliczeń numerycznych.
EN
Results of theoretical and experimental investigations of the flow around wing tips are reported. The analysis is starting with the earliest vortex model of Joukowsky wings, ending with double lifting surface model. The paper presents comparison of the latest model testing of vortex cavitation with numerical computations.
18
Content available Numerical investigation of the flow around wing tips
Koronowicz T., Tuszkowska T., Wilczyński L.
TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk
|
2000
|
Vol. 4, No 2
203-212
EN
The paper dwells with the problems of modelling the flow around a wing tip and tip vortex cavitation. The theoretical bases of the vorticity method and vorticity calculation models for design and estimation of hydrodynamic characteristics of the hydrofoil are presented. Basic assumptions of a double layer lifting surface model are described. A double layer lifting surface model enables proper modelling of the phenomena occurring in the flow around a hydrofoil tip and especially the generation of a free vortices system.
19
Content available remote Theoretical and experimental investigation of the generation mechanism of tip vortex and vortex cavitation
Koronowicz T., Tuszkowska T., Wilczyński L.
Polish Maritime Research
|
2000
|
Vol. 7, nr 2
3-7
EN
The paper presents the problem of tip vortex cavitation inception in the flow around a screw propeller. The most recent experimental and theoretical results concerning mechanisms of tip vortex generation and vortex cavitation inception are reported.
20
Content available A computer program for determination of acoustic pressure field related to ship hull and propeller operation
Koronowicz T., Szantyr J.
Hydroacoustics
|
1997
|
Vol. 1
163--168
EN
The paper presents the results of analysis of the influence of water viscosity and propeller operation effects on the hydroacoustic pressure field generated by the moving ship hull. The analysis is based on the results of calculations using the program based on Computational Fluid Dynamics for the hull flow and lifting surface method for the propeller flow.
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