English Polish
Politechnika Morska w Szczecinie

DSpace Home

DSpace/Manakin Repository

Browsing by Author Ghiasi, Mahmoud:

  • Safaei, Aliakbar; Ghassemi, Hassan; Ghiasi, Mahmoud (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    In line with the ambition of ship-owners to preserve capital and reduce operational costs, the selection of an optimum, safe and secure route for an envisaged voyage has always been a challenge for ship-owners, masters, and engineers. Due to the many complexities and parameters that affect the selection of an optimal route, the topic has become very interesting to many researchers. Each of the parameters affecting the process of route selection has its own values and weights, and these values change depending on specific situations and objectives. This sensitivity to context increases the difficulty selecting the optimum route. In this research, the optimization of a tanker-sized VLCC voyage for predefined and different routes is addressed in order to identify the optimum route. To reduce the number of variable parameters, major values have been assigned to the ship profile and sea conditions. The time domain analysis and the solution of equations of motion are then performed. The proposed route is designed by using a Bezier curve, and this route is then optimized with the objective of decreasing fuel consumption using the Fletcher-Powell method. The resulting optimized route shows a 3.7% savings in fuel consumption
  • Ganjgani, Arman Aghaei; Ghassemi, Hassan; Ghiasi, Mahmoud (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    This paper investigates the effect of buoys and a clump weight on the mooring lines and the dynamic response of the floating platform. The full-scale of the OC4-DeepCwind semisubmersible FOWT platform is analyzed using the boundary element method (BEM) with ANSYS-AQWA software, when considering regular wave conditions. Platform motions and mooring line tension in the surge, heave, and pitch are presented and discussed in the time domain analyses (TDA) and frequency domain analyses (FDA). Validation is performed by compression of the platform motion RAO and the fairlead tension RAO magnitudes in the surge, heave, and pitch (for both numerical and experimental data) under seven sea states’ regular waves. The results show that increasing the number of buoys at a constant volume decreases the surge and pitch motion amplitude, while the heave motion increases slightly. Adding the buoy and clump weight (type 1) to the mooring line reduces the oscillation amplitude tension. In addition, raising the number of buoys increases the oscillation tension.

Search repository

Advanced Search

Browse

My Account

RSS Feeds