Numerical Simulation Of The Aerodynamic Characteristics Of Two-Dimensional Marine Sail

In the world's energy shortage situation, it has been paid more and more attention on the sail which is used for ship assistance. And the differences of aerodynamic characteristics will make an impact on the capability of ship assistance. This paper studies the aerodynamic characteristics of two-dimensional sail, including unflexible sail and flexible sai. The applicable attack angle and the calculating accuracy of different methods are discussed.This paper's conclusions will give aid to make Optimization of sails.The emphasis and difficulty of this paper is the numerical simulation of two-dimensional flexible sail,and its basic is stream function method which is used for simulating the two-dimensional unflexible sail. So, this paper discusses the numerical simulation of two-dimensional unflexible sail first,and then investigates the numerical simulation of two-dimensional flexible sail.The author chooses two airfoils of unflexible sail——thinwing aerofoil and NACA aerofoil,utilites three methods to process numerical simulation of their aerodynamic characteristics. Firstly, the author derivatives detailedly implementation steps of stream function method and impenetrability method based on vortex distribution panel method theory, and uses the two methods to process numerical simulation of the aerodynamic characteristics of thinwing aerofoil and NACA aerofoil. It's indicated that the results have high accuracy in small attack angle range. Secondly, the author utilizes a commercial software namely FLUENT to simulate the aerodynamic characteristics of thinwing aerofoil and NACA aerofoil at different flow's attack angle in steady viscid fluid. The results indicate that FLUENT simulation results have high accuracy, not only in small attack angle, but also in large attack angle, it approximates the trial data. Finally, this paper investigates the method that how to use this two aerofoil aerodynamic analyse softwares:Profili and Airfoil, and as an example, the aerodynamic characteristics of NACA aerofoil are calculated. It's indicated that the simulation results have high accuracy in small attack angle range and approximate the trial data.For two-dimensional flexible sail, this paper researches the thinwing aerofoil(ignore thickness) based on the theory of stream function method, uses Jackson's numerical iterative method to numerical simulate its aerodynamic characteristics. It's indicated that the simulation results gained from this method approximate the trial data in small attack angle ranges and have referrence value.