Hızlı bir feribotun düşey ivmelenmesinin T-Foil ve trim tab sistem

his study is concerned with the active T-foil placed near the bow on the keel line of the fast ferry and two active trim tab controls placed at the stern to improve the maritime performance of a fast ferry, whilst improving the comfort and safety of passengers and crew. In the scope of the study, the vertical direction of the fast ferry under the random head waves, heave and pitch motions were taken into account. For the control of T-foil and trim Tabs, PID and LQR control methods were used. The purpose of these controllers is to reduce the acceleration of the heave and pitch motions of the fast ferry by changing the operating angles of the T-foil and trim tab wings. A random wave model was created using the Pierson-Moskowitz model, and simulations were done assuming that the fast ferry was subjected to random head waves. Finally, in order to see the effect of vertical acceleration on passengers, the rate of seasickness (MSI) change of the fast ferry in uncontrolled and controlled states was examined. Mathematical models of fast ferry, T-foil and trim tab and their simulations were carried out in MATLAB / Simulink environment. The simulation results show that T-foil and trim tab Active systems can effectively reduce vertical acceleration by improving heave and pitch motions.Bu çalışma, hızlı bir feribotun denizcilik performansını iyileştirmek, yolcu ile mürettebatın konfor ve güvenliğini artırmak için hızlı feribotun omurga hattında pruvaya yakın bir noktaya yerleştirilen hareketli T-foil ve kıç tarafına yerleştirilen iki adet hareketli trim tab kontrolü ile ilgilidir. Çalışma kapsamında baştan gelen düzensiz dalgaların etkisindeki hızlı feribotun düşey yönde yaptığı baş kıç vurma ve dalıp çıkma hareketleri dikkate alınmıştır. T-foil ve trim tabların kontrolü için ise PID ve LQR kontrol yöntemleri kullanılmıştır. Bu kontrolörlerin amacı, T-foil ve trim tab kanatlarının çalışma açılarının değiştirilmesiyle hızlı feribotun pozisyonunu kontrol ederek baş kıç vurma ve dalıp çıkma hareketlerinin ivmelenmesini azaltmaktır. Pierson-Moskowitz modelinden yararlanılarak düzensiz bir dalga modeli oluşturulmuş ve çalışmalar hızlı feribotun baştan gelen düzensiz dalgalara maruz kaldığı varsayılarak yapılmıştır. Son olarak düşey ivmelenmenin yolcular üzerindeki etkisini görebilmek için hızlı feribotun kontrolsüz ve kontrollü durumda deniz tutması oranı (MSI) değişimi incelenmiştir. Hızlı feribotun, T-foilin ve trim tabın matematiksel modelleri MATLAB / Simulink ortamında elde edilerek simülasyonları gerçekleştirilmiştir. Simülasyon sonuçları, T-foil ve trim tab aktif sistemlerinin baş kıç vurma ve dalıp çıkma hareketlerini iyileştirerek düşey ivmelenmeyi etkili bir şekilde azaltabildiğini göstermektedir

The overall motion sickness incidence applied to catamarans

ABSTRACT The Overall Motion Sickness Incidence is applied to the hull form optimization of a wave piercing high-speed catamaran vessel. Parametric hull modelling is applied to generate two families of derived hull forms, the former varying the prismatic coefficient and the position of longitudinal centre of buoyancy, the latter instead the demi-hull separation. Several heading angles are analysed in a seaway, considering all combinations of significant wave height and zero-crossing period under two operating scenarios. The optimum hull is generated and vertical accelerations at some critical points on main deck are compared with the parent ones. Finally a comparative analysis with the results obtained for a similarly sized monohull passenger ship is carried out, in order to quantify, by the OMSI, the relative goodness in terms of wellness onboard of monohulls and catamarans, as a function of sea states and operating scenarios

Fast ships models for seakeeping improvement studies using flaps and T-foil

Fast ships are taking a relevant role with a clear interest for military purposes. Fast sea transportation encounters several problems to be solved. This article refers to the difficulties originated by brisk vertical motions. The waves encountered by fast ships induce such vertical motions, and this has negative effects: navigation risks, sea sickness, structural damages, and load displacement. It is also interesting for military uses to stabilize the ship when an aircraft is landing or when precision firing is required. By means of submerged actuators, it is possible to alleviate vertical motions. In this research, a pair of transom flaps and a T-foil near the bow are used to counteract the waves. These actuators must move with the maximum efficiency, taking into account the dynamical characteristics of the ship. As a consequence, there is a problem of automatic control design. To carry out this design, it is important to obtain mathematical models of all the aspects involved in the problem: the ship, the waves, the actuators, and the effect on crew and comfort. The aim of this paper is to present the development of these models and the use of them for problem analysis and control design