Dynamics Analysis Of The Deep-towed Systems

Deep Towed Vehicles (DTVs) usually have three components: mother ships, towed-cables and towed vehicles. DTVs have no propulsion and are towed by surface ships. They can carry various equipments to do near- seafloor, long- distance, or long- time surveys for the studies of seabed topography, shallow- sea geology, physical and chemical water, Etc. Because of all above, with the development and utilization of the deep sea, DTVs are widely used in many international oceanic surveys.The dynamics study of towed-cables is very important to towed systems. But, after over half a century, it still has some motion and calculation problems of towed-cables to solve. And, to solve these problems, we should know the underwater characteristic of the towed-cables. In this paper, the dynamic model of a towed-cable was built and improved to be suitable to DTVs. Then, the non-linear dynamic problem of DTVs was solved and the underwater characteristic of DTVs could be forecasted. This can provide a reference for the design and operation of DTVs.In this paper, a towed-cable was discretized in space and time, and a dynamic model of the towed-cable was built. Then, at discrete nodes, the balance equations of moment were established. And the non-linear equations were solved by translating them to linear ones. By solving linear equations, the configuration, the force and the motion of the towed-cables in different times could be got. In this paper, the calculation program of towed-cables was written with MATLAB. Then, based on the dynamic model about the towed-cable, a towed-vehicle was attached to its endpoint to form the dynamic model of DTVs. The MATLAB program was improved to make it suitable for DTVs. With this program, we calculated the towed system of Towed Vehicle Interface Project sponsored by"863"Fund.At last, with the MATLAB program of the towed-cables and the DTVs, a graphical user interface was built up by MATLAB GUI programming. With this interface, the source-program can be controlled and some elements of the program can be modified for different towed systems. With this interface, the source-program can be run and the static or dynamic configuration of the towed-cables can be got in different windows. The GUI makes the calculation process simple and direct.