4.3 Oblique motion with propeller
Fig. 13 presents an example of computed flow around a ship with rudder and propeller in a oblique motion, β =10.0deg., δ=10deg condition. The effect of propeller is applied CFD simulation by using the infinitely bladed propeller model.
An example of computed flow around a ship with propeller in a oblique motion.
Fig.14 shows the comparison of calculated wake distribution of propeller acting in oblique motion. It is shown that a propeller accelerated flow of the rudder circumference is shortened by oblique motion and by taking a rudder angle.
Comparison of calculated wake distribution at A.P. section in oblique motion
a) β=0.0deg., δ=0deg., with propeller
b) β=10.0deg., δ=0deg., with propeller
c) β=15.0deg., δ=0deg., with propeller
d) β=10.0deg., δ=-10deg., with propeller
In this study, the authors applied CFD simulation techniques, expected to yield a variety of applications in the field of maneuverability predictions for ships, from view point of the flow around rudder behind hull and propeller during oblique motion. CFD simulations were used to calculate the interactive force from the rudder acting on the hull and the rudder normal force characteristics behind the ship. The simulation results were compared to observations from scale model tests. CFD simulations were found to predict with accuracy changes in rudder normal force behind the ship generated during oblique motion.
A number of areas require further investigation. For example, we need to ascertain whether CFD simulations are suitable for evaluating the impact on the rudder force by factors such as the turning motion of the ship's hull and hull design.
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