Calculating The Motion Attitude Of The Cylinder Buoy And Experiment Research

In many developed countries, buoy is an important tool used for observations and exploration. With the gradual development of the oceans, the drag buoy is used in engineering practice slowly. Flow around a cylinder is a classical mechanics problem, applied widely in the project. So researching the motion attitude and flow field of the drag buoy is valued in the theoretical research and the practical application of engineering.In this article we make use of the turbulence model of the FLUENT software, which calculates the hydrodynamic performance of the single cylinder under different angle of dip in the steady stream. Then we analyze the force and moment of the cylinder. In the restriction of the force balance and the moment balance, so we can know the steady state of the buoy under the water or in the water.When the cylinder under the water, we can calculate the flow around the cylinder respectively by the k-εand Realizable k-εturbulence model. The calculations show that the results calculated by the Realizable k-εare larger than the result calculated by k-ε.But the angles of the force balance and the moment balance are different. This shows that there are errors in the calculations. And we calculate the flow around the two-dimensional cylinder and three-dimensional cylinder. Then we compare the calculations and the classic literature, discovering that when the movement simulated by the k-εturbulence model, the error is small in the two-dimensional cylinder, but large in the three-dimensional cylinder.When the cylinder moves in the water, we calculate the angle of the force balance and the movement balance of the cylinder in the different drainage volume. Then we use the angle and obtain the drainage volume in the steady state. This illustrates that the physical model is valued in the simulation of the flow around the cylinder. According to the experiment data, we continuously modify and correct the method.When the cable is broken off, the buoy floats freely. On basis of the buoy floating freely, we propose a method for converting the buoy floating freely experiment. The converted results are approximate, comparing with the results of the FLUENT. The method is useful, we can modify it according to the experiment data of the buoy scale floating freely.