Sharif Digital Repository

Special geometrical sections, known as “duct”, which can be installed on merchant vessels stern in order to improve propulsion system and propeller performance, today have evolved considerably. The force which produces by the propeller depends on efficiency of propulsion system. In the way of improving the efficiency of propulsion systems, by using these special geometrical sections, to much research have been done from the mid-twentieth century. The Wake Equalizing Ducts (WEDs) in addition to conduct the more uniform fluid flow to the propeller disk (which causes to improve the propeller operation), affect on flow separation in ship stern zone and will decrease the separated flow zone.... 

In this thesis, an attempt is made to provide a hydro-aerodynamic mathematical model of a 20-bird batboat with a combined wing with catamaran body shape equipped with a parachute propulsion system in the rising phase of the surface and optimizing the propulsion system to reduce the take-off phase of the bird's boat. For this purpose, the hydro-aerodynamic modeling of the bird's boat from the rest period to the cruise phase has been considered, taking into account the parachuting system. For this purpose, three methods are considered. In the first method, combinatorial wing aerodynamic modeling and hydrodynamic modeling of the radar catamaran float were first studied. Finally, in the case of...