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1
Content available How to divide the global resistance change into the components related to the pushing propeller and the pulling propeller of the double-ended ship
Jarzyna H.
Polish Maritime Research
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2008
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nr 2
12-14
EN
The division of the global resistance change [wzór] due to the simultaneous action of the pushing (SR) and pulling(SD) screw propellers into the components [wzór] and [wzór] can be done by taking into account two different procedures and different hypothetical assumptions given in the form of the division coefficients (Aj)R and (Aj)D, the same in each procedure. In the procedure no1:[wzór] In the procedure no 2: [wzór] Two necessary conditions were formulated to be fulfilled when selection of the coefficients (Aj)R and (Aj)D is done. The results of the analysis are univocal. Among the possible division coefficients only one pair of them fulfills the formulated conditions. This pair is: [wzór]
2
Content available Complex investigations of a cycloidal propeller in Ilawa in the 1960s
Jarzyna H.
Polish Maritime Research
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2007
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S 2
18--19
3
Content available remote Selection of the most suitable method to split the resistance increment into components related to individual propellers of double-ended ferry
Jarzyna H.
Archives of Civil and Mechanical Engineering
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2007
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Vol. 7, no 3
143-150
EN
The resistance increment [...] measured in model propulsion tests of a double-ended ferry with the pushing aft propeller SR and the pulling fore propeller SD is to be split into two components: [...] and [...] related to each of the propellers. The splitting procedure based on the measured magnitudes is possible only when additional assumptions are made. Two procedures are presented in this paper. The first procedure, i = l, is directly related to the components of resislance increment [...] and [...]. The second procedure, i = 2, is related lo the components [...] and [...] attributed to individual propellers. In both procedures the same assumptions are used for splitting. Proposed assumptions are based on the proportion of propeller thrust TR and TD, or on the proportion of the delivered power [...] and [...]. Procedures combined with assumptions define the methods and are denoted Kij where subscript refers to the assumption. Two prerequisites were formulated. Both have to be satisfied by methods of practical importance: Above prerequisites are satisfied only by the K11 and K21 methods. The methods KI3 and K23 satisfy only the first prerequisite.
PL
Pomierzoną w modelowych badaniach napędowych promów symetrycznych globalną zmianę oporu kadłuba [...] wskutek działania śruby rufowej SR i dziobowej SD należy podzielić na składniki [...] i [...] związane z każdą ze śrub. Podział taki możliwy jest pod warunkiem przyjęcia dodatkowych założeń. Praca analizuje możliwe założenia w dwu grupach proceduralnych. Procedura pierwsza, i = l, wiąże bezpośrednio zmiany [...] i [...] z hipotezami zmian. Procedura druga, i = 2, wiąże zmiany [...] z tymi samymi hipotezami zmian. Hipoteza pierwsza, j=l, zakłada proporcjonalność zmian z obu procedur do mierzalnych naporów TR i TD). Hipoteza druga, j = 2, zakłada proporcjonalność zmian z obu procedur do mierzalnych mocy PDR i PDD. Rozpatruje się kryteria zmian określane jako Kij. Sformułowano dwa warunki, jakie spełniać winny poszczególne kryteria akceptowalne do stosowania. Stwierdzono, że oba warunki są spełnione, gdy stosuje się kryterium K11 i kryterium K21. Kryteria K13 i K23 spełniają jedynie warunek pierwszy.
4
Content available remote Propulsion prognosis for a ship according to the zero version (0-JH) of the new power prediction method
Jarzyna H., Tuszkowska T.
Polish Maritime Research
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2002
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Vol. 9, nr 3
3-7
EN
The ITTC-78 power prediction method can be divided into three groups of procedures: R TS - procedures, T BS - procedures and the Q BS - procedures. Only the Q BS - procedures were analyzed in the paper [7] where a new approach to the determination of Q BS and n S parameters was given. A new idea of the equivalent open propeller is the basic difference between the Q BS - ITTC procedures and the new Q BS - procedures called JH ones. This paper presents the numerical results of power prediction for a selected ship, obtained with the use of the zero version (0-JH) of the new method (in its 0-JH3 variant). A comparison between the ITTC-78 method, 0-JH3 method and sea trial results was also given.
5
Content available remote On the power prediction methods in the preliminary ship design stage
Jarzyna H., Tuszkowska T.
Polish Maritime Research
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2001
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Vol. 8, nr 3
3-7
EN
The ITTC-78 power prediction method can by divided into three groups of procedures: RTS- procedures, TBS- procedures and the QBS- procedures. Only the QBS- procedures are analyzed in this paper. A new approach to the determination of QBS and nS parameters is proposed. Outline of the new methods is briefly presented. The new idea of equivalent open propeller is the basic difference between the ITTCQ BS- procedures and the Q BS-JH - procedures. The aim of this approach is to reduce the number of parameters needed to be corrected due to the scale effect and to generate a situation where the Q BS, n S and V TS parameters are of unique value independent of the subjective choice of averaging criteria.
6
Porównanie rezultatów obliczeń efektywnej prędkości średniej według jej różnych definicji w modelowych badaniach napędowych
Jarzyna H.
Zeszyty Naukowe Instytutu Maszyn Przepływowych Polskiej Akademii Nauk w Gdańsku
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1998
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nr 490/1452
1--24
PL
W pracy zaprezentowano, celem wnikliwego porównania, rezultaty obliczeń efektywnej prędkości średniej według jej dotychczasowej i nowo proponowanej definicji. Liczbowe potwierdzenie znajdują wszystkie konsekwencje wynikające z analizy stanu obecnego i proponowanych zmian. Podstawą obliczeń numerycznych były rezultaty modelowych badań napędowych BN18 bis specjalnie troskliwie zaprogramowanych
EN
The calculation results of effective mean velocity from the old and the new proposed definitione are presented to be compared. All consequences from the state of art. Analysis and from the proposed modifications were numerically verified. The results of the model propulsion test BN18 bis were the base of the numerical procedures. The test BN18 bis was programmed with special care.
7
A new method of determination of the constant factor CO of nominal velocity field transformation into the effective one
Jarzyna H.
Zeszyty Naukowe Instytutu Maszyn Przepływowych Polskiej Akademii Nauk w Gdańsku
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1998
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nr 487/1451
1--15
EN
A method is presented to determine univocally the constatnt factor CO of the nominal velocity field transformation into effecdtive one, without taking into account any mean value of the nominal velocity field and the effective mean value from propulsion test. The assumption has been made that the torque coefficient is to be calculated with enough accuracy in practice – using the correction factors being suitable veryfied.
PL
W pracy zaprezentowano metodę określania jednoznacznego stałego czynnika CO, transformacji nominalnego po1a prędkości w efektywne, nie biorąc pod uwagę żadnych wartości średnich nominalnego pola prędkości, ani też efektywnej prędkości średniej z badań napędowych. Poczyniono założenie, że współczynnik momentu śruby można wyznaczać na drodze obliczeń z wystarczającą dokładnością, w praktyce stosując odpowiednio weryfikowane współczynniki korekcyjne.
8
Content available remote The present and possible application of the mean effective velocity in Ship Hydromechanics
Jarzyna H.
Polish Maritime Research
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1998
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nr 4
2-8
EN
The calculation results of the effective mean velocity from the old and proposed new definition are presented for comparsion. All consequences from state-of-art analysis and the proposed modification were numerically verified. The results of the model propulsion test BN18 bis formed the base of the numerical producers. The test was programmed with special care.
9
Content available remote Effective mean velocity (EMV) and effective mean pitch (EMP) based on a common definition
Jarzyna H.
Polish Maritime Research
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1998
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nr 3
2-5
EN
A definition is given of the effective mean velocity (EMV) in model propulsion test, being simultaneously the definition if effective mean pitch (EMP). In this way it is possible to replace the radial pitch distribution of a SB-propeller in behind condition by a constant pitch of a SBmod propeller in an uniform velocity which is the effective mean velocity univocally determined, independent of the averaging criteria (thrust, torque, or power identity).
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