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Tytuł:
Susceptibility of the roll equation to the bifurcation phenomenon depending on the damping coefficient value and form of the roll damping formula
Autorzy:
Wawrzyński, W.
Powiązania:
https://bibliotekanauki.pl/articles/135685.pdf
Data publikacji:
2017
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
ship stability
ship rolling
bifurcations
roll resonance
roll damping coefficient
formulas
Opis:
This paper deals with the susceptibility of the roll equation to the bifurcation phenomenon depending on the damping coefficient value and form of the roll damping formula. Generally, the bifurcation phenomenon depends mainly on the shape of the righting arm curve (GZ curve), but roll damping also has a significant impact. The commonly used formulas for roll damping are presented, as well as values of the linear equivalent roll damping coefficient, calculated according to the simple Ikeda method. Values of the linear equivalent roll damping coefficient were calculated for a wide spectrum of roll amplitudes and roll frequencies for two ships. The loading conditions for these ships were selected to show different GZ curve characteristics. One ship has a softening spring characteristic and the second has a hardening spring characteristic. For these two ships, a number of calculations of roll spectra are presented where the bifurcation phenomenon occurs. Calculations were made for different damping coefficient values and forms of the roll damping formula.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2017, 52 (124); 161-169
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wykorzystanie techniki GPS do wyznaczenia kątów heading, pitch i roll. Cz. 1
Utilization GPS Technics for Determination Heading, Pitch and Roll Angles. Part 1
Autorzy:
Wierzbicki, D.
Krasuski, K.
Powiązania:
https://bibliotekanauki.pl/articles/403376.pdf
Data publikacji:
2016
Wydawca:
Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
Tematy:
GPS
heading
pitch
roll
Opis:
W artykule przedstawiono eksperyment dotyczący wyznaczenia kątów heading, pitch i roll z wykorzystaniem technologii GPS. W tym celu stworzono autorski program HPR_GPS, którego kod źródłowy napisano w języku Scilab 5.4.1. Zaprezentowano zasadę działania aplikacji HPR_GPS oraz przedstawiono algorytm wyznaczenia kątów heading, pitch i roll. Dodatkowo, porównano otrzymane wyniki kątów z programu HPR_GPS ze źródłowymi danymi z INS. Średnia różnica dla kąta heading wynosi 0,29° z błędem średnim 5,96°, dla kąta pitch wynosi 4,98° z błędem średnim 1,62°, zaś dla kąta roll wynosi 0,06° z błędem średnim 2,31°.
This article presents an experiment concerning the designation of heading, pitch and roll angles using GPS technology. For this purpose, authorial HPR_GPS software has been created, the code source of which was written in Scilab 5.4.1 language. Operation of application was presented and an algorithm of estimation of heading, pitch, and roll angles was showed. Additionally, final results of angles from HPR_GPS software were compared with raw INS data. Based on comparison, mean difference for heading angle is equal to 0.29° with standard deviation of 5.96°, for pitch angle it is equal to 4.98° with standard deviation of 1.62°, and for roll angle it is about 0.06° with standard deviation of 2.31°, respectively.
Źródło:
Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa; 2016, 7, 1 (23); 113-125
2081-5891
Pojawia się w:
Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ship nonlinear roll motion identification using artificial neural network
Autorzy:
Mousavi, Seyed Mohamadreza
Khoogar, Ahmad Reza
Ghassemi, Hassan
Powiązania:
https://bibliotekanauki.pl/articles/24202591.pdf
Data publikacji:
2022
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
nonlinear roll motion
dynamic identification
DTMB 5415
roll decay
artificial neural network
Opis:
The solution of the nonlinear equation for a ship’s rotational motion around its longitudinal axis, even with simplifying assumptions, is complicated. This oscillatory motion, which is known as the roll motion, is generated when the ship sails in the waves, and the irregular behavior of the waves causes time-varying dynamics. Calculating the ship’s roll response is possible by determining roll equation coefficients. In the current study, the coefficients were determined from the dynamic response of the ship using a training feed-forward neural network. The training was carried out in two modes: as a free swing in calm water and forced oscillation in irregular waves. The DTMB 5415 vessel was selected as the case study ship. The results of the simulation by the neural network were validated by numerical analysis and model test results.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2022, 72 (144); 65--74
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Overview of Roll Stabilizers and Systems for Their Control
Autorzy:
Kula, K.S.
Powiązania:
https://bibliotekanauki.pl/articles/117383.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
Marine Controllers
Roll Stabilizer
Fin Stabilizer
Non-Linear Process
Multivariable Dynamic Process
Roll Motion
Computer Techniques
Anti-Roll Tanks
Opis:
Ship roll motion in waves can be characterized as a strongly non-linear and multivariable dynamic process which is more affected by disturbances, in general, than by the maximal controlling parameter. The article presents methods of roll motion compensation, the majority of which have been used on ships for many years. Although they are not capable of reducing permanently the error to zero, their potential has still not been used to the full. The operational efficiency of roll motion compensators can be improved using control systems. Research activities are in progress to check the applicability of advanced control methods making use of modern computer techniques. Some of them are mentioned in this paper.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2015, 9, 3; 405-414
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Virtual ship’s roll decay test with the use of CFD technique
Autorzy:
Krata, P.
Jachowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/243570.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
sea transport
ship stability
roll simulation
roll decay test
computational fluid dynamics
Opis:
Since safety of navigation is related to the stability performance of a ship, the transverse stability is routinely calculated and measured. One of the crucial experimental approach is a roll decay test. Although, an obtained result of the roll decay test carried out on the full-scale ship needs to be compared to a benchmark enabling an estimation of the relevant stability. Nowadays such a benchmark is just based on the simplified GM-based IMO-recommended formula. This research aims at the more sophisticated method of ship’s natural period of roll estimation and thus her stability assessment. The CFD (computational fluid dynamics) technique is applied and the result of the free roll simulation is compared to the solution of a roll equation. The one degree-of-freedom roll equation is applied with regard to the nonlinear ship righting moment and the nonlinear damping moment obtained according to Ikeda’s method. The six degrees-of-freedom simulation of ship’s roll decay test was carried out by the use of FlowVision code utilizing the Reynolds-averaged Navier–Stokes equation with regard to the turbulent flows based on the eddy viscosity concept. The semi-empirical k-ε turbulence model was applied. Thereby, the CFD-based approach allows to get rid of any assumptions regarding the value of the damping coefficient, which is an advantage over the roll equation based approach.
Źródło:
Journal of KONES; 2016, 23, 2; 215-221
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
To determine the stability of the metrobus in unstable driving modes
Autorzy:
Marchuk, Roman
Marchuk, Nazar
Sakhno, Volodymyr
Poliakov, Viktor M.
Powiązania:
https://bibliotekanauki.pl/articles/1838347.pdf
Data publikacji:
2021
Wydawca:
Sieć Badawcza Łukasiewicz. Przemysłowy Instytut Motoryzacji
Tematy:
metrobus roll
acceleration
stability
trailer
Opis:
Recently in many cities of the world began to introduce so-called «metrobus» or BRT (Bus Rapid Transit) systems, which became a cheaper alternative to the metro and other rail transport, in particular trams. The aim of the work is to determine the stability indicators of the metrobus in the transitional traffic modes, in particular when performing such manoeuvres as «steering wheel jerk» and «shuffle». For this purpose, the equations of metrobus plane-parallel motion are supplemented by equations of the links of the road train in the vertical plane by halopilation (tangage, trim) and roll. The critical straight-line speed of the three-link metrobus has been determined, which was 32,06 m/s, and this speed is independent of the corners of the steering wheels of the bus and the trailer links. It has been shown that as the steering wheel angle of the bus increases, the difference in the folding angles of the bus increases, with the second folding angle significantly exceeding the first, especially considering the roll of the metrobus body. It has been established that the greatest rolls and loads of the metrobus axles are those of the last trailer, which is the limiting factor for the critical speed. The lateral accelerations of individual metrobus links and their yaw velocity when performing the manoeuvre «steering wheel jerk» and «shuffle, Sl = 24 m», show that both the bus and the second trailer link are a limiting factor when performing various manoeuvres, but the acceleration value does not exceed the permissible 0.4 g, so its stability under these conditions is ensured.
Źródło:
Archiwum Motoryzacji; 2021, 91, 1; 63-79
1234-754X
2084-476X
Pojawia się w:
Archiwum Motoryzacji
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Czas zatrzymany – amerykańska nostalgia za epoką rock’n’rolla
Time on Hold – The American Nostalgia for the Rock and Roll Era
Autorzy:
Włodek, Patrycja
Powiązania:
https://bibliotekanauki.pl/articles/28408974.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Sztuki PAN
Tematy:
lata 50.
Reaganizm
rock’n’roll
kontestacja
1950s
Reaganism
rock and roll
constestation
Opis:
Lata 50. to szczególny okres w historii Stanów Zjednoczonych. Ta jedna z najbardziej mitologizowanych i fetyszyzowanych epok XX w. w kulturze Ameryki; jest jednocześnie jedną z bardziej ambiwalentnych i podatnych na zewnętrzne oczekiwania co do jej wizerunku kreowanego w kinie. Lata 50. – rozpięte między idealną all American erą Eisenhowera a narodzinami kultury młodzieżowej i ruchów społecznych, które diametralnie zmieniły Amerykę w epokach kolejnych – już w punkcie wyjście były ambiwalentne, co odbijało się z jednej strony w clean teen movies, a z drugiej w melodramatach rodzinnych. Szczególne znaczenie zyskały w latach 80., kiedy nostalgia za erą rock’n’rolla jako część „Reaganoretro” i „Reaganizmu”, czyli konserwatywnego nurtu w kinematografii, wyparła społeczny kontekst i tło historyczne, zamieniając paradoksalne lata 50. w serię popkulturowych, często pustych ikon.
The 1950s are a special period in the history of the United States. It is one of the most mythologised and fetishised eras in the American culture of the 20th century. At the same time it is one of the most ambiguous periods, susceptible to external expectations as to its image created in the cinema. The 1950s – stretching from the ideal all American era of Eisenhower and the birth of youth culture and social movements that radically changed America in the following periods – was ambivalent already at the point of exit, which was reflected on the one hand in clean teen movies, and on the other hand in family melodramas. In particular 1950s gained significance in the 1980s, when the nostalgia for the rock and roll era, as part of Reaganism and Reagan-retro, that is a conservative trend in the cinema, ousted the social context and historical background of the era, turning the paradoxical 1950s into a pop culture theme park full of often empty icons.
Źródło:
Kwartalnik Filmowy; 2014, 86; 113-133
0452-9502
2719-2725
Pojawia się w:
Kwartalnik Filmowy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Review on Parameters Influencing the Rice Breakage and Rubber Roll Wear in Sheller
Autorzy:
Prabhakaran, P.
Ranganathan, R.
Muthu Kumar, V.
Rajasekar, R.
Devakumar, L.
Pal, S. K.
Powiązania:
https://bibliotekanauki.pl/articles/351700.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
rice
rice breakage
rubber roll sheller
Opis:
The present review deals with parameters influencing the rice breakage during rice milling operations and the effect of rubber roll Sheller in rice husk removal process. The main objective of rice milling system is to remove the husk and bran layer to produce the white rice. In this process, rubber roll sheller is used to remove husk from the grains by friction process. If the rubber material is too soft, there may not be sufficient shear force to husk the paddy. Wear will be minimum for rubber material with high hardness but indeed it pronounce the breakage of rice. Hence, for efficient husking the rubber roll material should possess the balance of physico-mechanical properties. Rice breakage depends on several other parameters like the type of harvest, drying temperature, drying methods, physical characteristics of paddy, husking characteristics, paddy moisture content, rubber roller speed, rubber roll pressure, paddy feed rate and fissures. Rubber roll wear depends on the type of rubber material attached to the roller, feed rate, roller speed, pressure etc.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 3; 1875-1880
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of rotation angles based on GPS data from a UX5 Platform
Autorzy:
Wierzbicki, D.
Krasuski, K.
Powiązania:
https://bibliotekanauki.pl/articles/114355.pdf
Data publikacji:
2015
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
GPS
heading
pitch
roll
Kalman filter
Opis:
Data integration from INS and GPS sensors is applied in aeronautical navigation as a basic conception for determination of aircraft position. A GPS sensor is used to estimate coordinates (X, Y, Z) and velocity (Vx, Vy, Vz) also in a navigation solution. On the other hand, an INS sensor provides rotation angles (heading, pitch and roll) and acceleration parameters (Ax, Ay, Az). The GPS sensor is preferred to obtain an approximate value of rotation angles. In this paper, the results of studies on determination of heading, pitch and roll angles using GPS technology are presented. For this purpose, GPS data from a single-frequency L1 receiver from a UX5 platform were used. Calculations were executed in the HPR_GPS software, whose source code was written in Scilab 5.4.1 language. The software operation and an algorithm for estimation of heading, pitch, roll angles there is described. The preliminary results of rotation angles from the HPR_GPS software show that heading, pitch and roll values are very similar to raw INS measurements. The mean difference between the GPS data (after Kalman filter operation) and the INS data for the heading angle is equal to 0.32( with a standard deviation of 5.41(, for the pitch angle is equal 4.98( with a standard deviation of 5.06( and for the roll angle is about 0.06( with a standard deviation of 0.69).
Źródło:
Measurement Automation Monitoring; 2015, 61, 11; 516-520
2450-2855
Pojawia się w:
Measurement Automation Monitoring
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Problemy pomiaru kąta przechylenia na obiektach ruchomych
Problems of measuring the roll angle on moving objects
Autorzy:
Gałach, A.
Dąbrowski, W.
Powiązania:
https://bibliotekanauki.pl/articles/275341.pdf
Data publikacji:
2010
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
pomiary kąta przechylenia
roll angle measurement
Opis:
W artykule przedstawiono metody pomiaru i estymacji kąta przechylenia na obiektach mobilnych. Przedstawiono wybrane metody pomiaru kąta przechylenia oraz opisano sposób integracji tych pomiarów. Opis metod pomiarowych zilustrowano doświadczalnymi wynikami uzyskanymi podczas badań laboratoryjnych i na wybranych obiektach.
The paper presents the methods of roll angle measurement and estimation on moving objects. The article describes selected methods of roll angle measurement as well as the algorithms of measurements integration. Discussed methods are illustrated with experimental results obtained in laboratory and during tests on selected objects.
Źródło:
Pomiary Automatyka Robotyka; 2010, 14, 2; 722-731
1427-9126
Pojawia się w:
Pomiary Automatyka Robotyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the process of double - deck bus rollover at the avoidance of an obstacle having suddenly sprung up
Autorzy:
Prochowski, L.
Zielonka, K.
Muszyński, A.
Powiązania:
https://bibliotekanauki.pl/articles/246787.pdf
Data publikacji:
2012
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
transport
buses
road safety
buses roll over
Opis:
A critical traffic situation has been explored where a double-deck bus may roll over. The factors that may cause critical situations during a bus drive have been analysed. Based on this, they may be categorised as being related to vehicle construction, vehicle operation, and road infrastructure. A situation has been chosen for the analysis where the bus without passengers avoids an obstacle having suddenly sprung up in front of the bus at a distance within which the bus cannot be stopped. A similar problem occurring in the case of a passenger car drive was analysed in study [6]; it was indicated there that the manoeuvre of avoiding an obstacle is definitely more favourable in comparison with the braking process. A model of the bus motion dynamics with 12 degrees of freedom was adopted. The vehicle trajectory was given in the form of a predefined input generated by a driver model. The course of the rollover process depends to a significant extent on the interaction between the tyres and the road surface. A semi-empirical non-linear TMeasy tyre model was chosen. The calculations were carried out with the use of a computing program specially built for this purpose, where a double-deck bus model and a driver model were applied to investigate the traffic situation as described above. The calculation results obtained have shown that the process of rollover of a bus without passengers emerges at the final stage of the obstacle avoidance manoeuvre at a speed exceeding 108 km/h. This has been confirmed by the course of changes in the pressure of wheels on the road. Based on the simulation calculations carried out, an attempt was made to determine, from the observed courses of changes in physical quantities, the values that might warn the driver about a situation of imminent danger of rollover of the double-deck bus and thus might affect driver's actions.
Źródło:
Journal of KONES; 2012, 19, 3; 371-380
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Good Rockin’ Tonight. Świt rock’n’rolla
Autorzy:
Szczerbakiewicz, Rafał Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/679451.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:
popular music, rock’n’roll, sound reproduction, ethnicity, racism
muzyka popularna, rock'n'roll, reprodukcja dźwięku, etniczność, rasizm
Opis:
The release of the first two Elvis Presley singles at Sun Studios is a breakthrough in the history of popular music, closing down the barriers between the ethnic varieties of the black and white subculture in the American South.Racial racism was then encountered with equally important social emancipation.The result of these changes was the birth of rock’n’roll as the universal egalitarian formula and the universal model of pop culture in the twentieth century.
Historia wydania dwóch pierwszych singli Elvisa Presleya w wytwórni Sun Studios jest dla dziejów muzyki popularnej przełomem likwidującym dotychczasowe, nieprzekraczalne bariery między etnicznymi odmianami subkultur „czarnej” i „białej” na amerykańskim Południu USA.Emancypacja rasowa spotykała się wówczas z równie istotną emancypacją społeczną.Efektem tych przemian były narodziny rock’n’rolla jako uniwersalnej formuły egalitarnego i powszechnego modelu kultury pop w XX wieku.
Źródło:
Artes Humanae; 2017, 2
2449-6340
Pojawia się w:
Artes Humanae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metal-morfozy. O języku dziennikarstwa metalowego w miesięczniku „Rock’N’Roll” w latach 1990–1991
Metal-morphoses On the language of metal journalism in the monthly ”Rock’N’Roll” in 1990-1991
Autorzy:
Florczyk, Tomas
Powiązania:
https://bibliotekanauki.pl/articles/520710.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Pedagogiczny im. Komisji Edukacji Narodowej w Krakowie
Tematy:
„Rock’N’Roll”
muzyka metalowa
publicystyka muzyczna
pisma rockowe
metal music
music journalism
rock magazines
Rock’N’Roll”
Opis:
Artykuł jest próbą analizy języka dziennikarstwa redaktorów muzycznych zajmujących się różnymi odmianami muzyki metalowej w miesięczniku „Rock’N’Roll” ukazującego się w latach 1990–1991. Okres po transformacji ustrojowej jest szczególnie interesujący dla rozwoju muzycznego dziennikarstwa, a magazyn „Rock’N’Roll” był najodważniejszym muzycznym periodykiem tamtych czasów. Cykle artykułów, recenzje koncertów, recenzje płyt, próby analizy zjawiska składają się na intrygujący obraz tego okresu w rozwoju muzycznej świadomości rodzimych odbiorców heavy metalu.
This article is an attempt at analyzing the language of journalists dealing with different types of metal music in the “Rock’N’Roll” magazine, which appeared in 1990-1991. The period after the transformation of the system in Poland is particularly interesting because of the development of music journalism, and the ”Rock’N’Roll” seems to be the bravest music magazine of that time. Cycles of articles, concert reviews, disc reviews, analysis of the phenomenon – all of them constitute a very intriguing picture of this period in the development of musical awareness of Polish heavy metal audience.
Źródło:
Annales Universitatis Paedagogicae Cracoviensis. Studia de Cultura; 2018, 10, 3 "Studia nad kulturą metalową"; 156-164
2083-7275
Pojawia się w:
Annales Universitatis Paedagogicae Cracoviensis. Studia de Cultura
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical and analytical approaches for roll motion analysis in regular longitudinal waves
Autorzy:
Peşman, E.
Kolukısa, D. C.
Taylan, M.
Powiązania:
https://bibliotekanauki.pl/articles/258476.pdf
Data publikacji:
2015
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
parametric roll motion
bifurcations
panel method
AQWA
Opis:
In this study numerical and analytical approaches were investigated in terms of accuracy of their results, practicality of solution and ability to reproduce the main features of the parametric roll phenomenon such as loss of stability and bifurcations in parametric roll motion analysis of ships. In general, single-degree-of-freedom analytical approach is based on reducing number of degrees of freedom from 3 to 1 by using the quasi-static Froude-Krylov assumption, incorporating heave and pitch effects by means of a time varying restoring moment. On the other hand, numerical approaches to motion of six and four degrees of freedom are based on three dimensional diffraction/radiation and potential flow theories. In summary, this paper reveals that analytical approaches are sufficiently adequate to obtain accurate practical results for this relatively complex phenomenon.
Źródło:
Polish Maritime Research; 2015, 3; 28-35
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prediction of ship motions in irregular waves based on response amplitude operators evaluated experimentally in noise waves
Autorzy:
Bielicki, Sebastian
Powiązania:
https://bibliotekanauki.pl/articles/1573664.pdf
Data publikacji:
2021
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
seakeeping
roll motions
noise
ship motions
experiments
Opis:
The most common methods for predicting ship roll motions in a specified sea state are direct measurements of motions in a representative irregular wave realisation (time domain) or calculations of motions from response amplitude operators (RAOs) in the frequency domain. The result of the first method is valid only for the tested sea state, whilst the second method is more flexible but less accurate. RAO-based predictions are calculated assuming a linear model of ship motions in waves. RAO functions are usually evaluated by means of tests in regular waves for a limited number of frequencies and a constant wave amplitude. This approach is time-consuming and the discrete form of the RAO functions obtained for a limited number of frequencies may lead to discrepancies in the prediction of seakeeping and often does not allow the actual amplitude of the response in resonant frequency to be determined. Another challenge is the appropriate selection of wave amplitude for tests due to the considerable influence of viscous damping on roll response in irregular sea waves. There are alternative methods for the experimental determination of RAO functions and one of them is presented in this study. The presented approach allows RAO functions to be evaluated in one run by the generation of irregular waves characterised by a white or coloured noise spectrum. This method reduces the experiment duration, with almost continuous RAO characteristics obtained. The flat (white noise) and linear (coloured noise) wave spectral energy characteristics are considered in the experiment and the obtained predictions are compared with the results of accurate measurements in irregular waves.
Źródło:
Polish Maritime Research; 2021, 1; 16-27
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 119

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