FBE- Gemi İnşaatı ve Gemi Makineleri Mühendisliği Lisansüstü Programı
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Gemi İnşaatı ve Gemi Makinaları Mühendisliği Ana Bilim Dalı altında bir lisansüstü programı olup, yüksek lisans ve doktora düzeyinde eğitim vermektedir.
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Sustainable Development Goal "none" ile FBE- Gemi İnşaatı ve Gemi Makineleri Mühendisliği Lisansüstü Programı'a göz atma
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ÖgeDevelopment of experimental captive and free-running manoeuvring systems and their cross-validation(Lisansüstü Eğitim Enstitüsü, 2021) Özden, Münir Cansın ; Gören, Ömer ; Sarıöz, Kadir ; 675786 ; Gemi İnşaatı ve Gemi MakineleriThe present PhD thesis describes a compact planar motion mechanism based captive and a GPS time pps synchronized free-running ship model manoeuvring test system designed and developed at Istanbul Technical University (ITU). The PMM system, designated as ITU-PMM, is particularly designed to be light and simple to be installed on the existing towing carriage in a 160-meter-long towing tank. The main components of the motion controller based system are; two servo-motors with high precision encoders, a reduction gear with very low backlash for yaw motion, precision linear motion ball-screws, a six component loadcell for force and moment measurements and a data acquisition system. ITU-PMM is primarily designed to perform standard captive manoeuvring tests, including the static tests such as steady drift and oblique towing with rudder deflection and the dynamic tests such as pure sway, pure yaw and yaw and drift. Additionally, since the servo motors are independently controlled, non-standard tests could also be carried out. In order to calibrate and validate the system, standard PMM tests were carried out with a SIMMAN (2008) benchmark case model (DTMB 5415) representing high speed displacement vessel. The measured forces and moment and the derived manoeuvring derivatives are compared with those obtained by major test facilities. The sensitivity of the system is verified by an uncertainty analysis. ITU Free Running System has modular measurement and propulsion systems, which are assembled on a battery, powered 5.72 m model of DTMB 5415. This model is propelled and steered by two servo motor groups. It is controlled by remote control and can also be run in semi-autonomous mode. The system allows users to set manoeuvring test parameters from shore and thus the model automatically performs indicated tests. The system has a PLC controller which drives the propeller and rudder servo motors, record, and arrange the data of time, position, heading and speed from a precise RTK (Real Time Kinetic) GPS. Roll and pitch data are recorded from inertial navigation system, angle and RPM are from encoders of servo motors. The use of pps (pulse per second) function of the GPS is extended to 10Hz by the offset adjustment feature of inertial navigation system, thus all the data collected from various sensors are synchronized by GPS time. This feature allows user to collect and arrange data without delay which is found crucial while analyzing dynamic motions such as zigzag experiments where the immediate ship responses to rudder actions are important. Utilizing the ITU Free-running system, turning circle and zig-zag tests are conducted at ITU Lake and the results are compared with the ones published by MARIN in SIMMAN (2014) Workshop. A repeatability analysis is also conducted to show the sensitivity of the tests. The cross-validation study is carried out by employing MMG method of Yasukawa and Yoshimura (2015) in the simulation of port and starboard turning circles by using the derivatives obtained from captive model tests conducted within the present thesis along with the derivatives by IIHR (Yoon (2005) and FORCE Technology (Simonsen (2004)). The results of turning simulations are compared with the turning circle results of ITU free-running test system. Simulation results showed a better agreement with that of the free running experiment when the derivatives are taken from Fr=0.410 tests. Turning diameter obtained by using derivatives from captive tests at Fr=0.280 results in a smaller diameter and Fr=0.138 derivatives gives even smaller diameter. There are numerous parameters in the present system-base model so that it is not easy to precisely pinpoint the cause of the fact that higher Froude number captive tests measurements are much more effective in predicting the manoeuvring characteristics. Anyhow, this may be attributed to the fact that higher speeds of the model result in higher Reynolds numbers which help to attain a flow regime which is relatively closer to the real case. Some of the topics which will be considered to be investigated after this thesis study are; It would be more fruitful both for the scientific manoeuvring community and also for Turkish Navy, if these tests are repeated with a model of a newly built ship and results are verified by full scale manoeuvring data. It is crucial to see the extent of the scale effect in manoeuvring characteristics when scaling from ship model to full size ships. Another following study may focus on conducting captive model tests in head and following regular waves and employ the derivatives together with wave excitation forces in the equations of motion. In a following study, model can be manufactured with rudders, propellers and other appendages such as shafts and struts. Captive tests can be conducted with propellers running at self-propelling conditions and by repeating the tests with different rudder angles in order to determine their influences on manoeuvring derivatives and parameters which are used in MMG method. Problems of manoeuvring may be said to be overcome by the use of AI and ML in the near future. Thus, further studies may be conducted to integrate AI and ML models into the problems of manoeuvring.