General Design, Evaluation And Application Of Of Towed Multi-parameter Profling System

One of research emphosis of Physical Oceanography is to observe the law which various factors are changing in the progress of middle and small scale in the ocean. Towed system is an effective tool to satisfy the above needs. The main task of this essay is to design a towed system which can be used in nearby sea area of China.The aim of this research is to finish design of a towed system of 200m depth profiling. This system combines multi-disciplinary sensors and its observing factors include temperature, salinity, pressure, chlorophyll-a, turbidity, dissolved oxygen, pH and nutrients. To assure the accuracy and depth of observation, it is necessary that the towed system should have good hydrodynamic character and smooth channel of water exchange.Meanwhile, the sensor should have fast response time and high precision. The main problems include general design of towed system, controllable wing design and intergration of optical sensors. Great research works are doing in this essay to achieve as follows:(1) In general, we applied the methods of rotating the controllable wing about its hydrodynamic center to vary its angle of attack, and towed body adopted the shape of torpedo, towed cable used flexible low drag fairings, which totally optimized hydrodynamics of towed system. Furthermore, the modular design of sensor and highly integrated software satisfy the normal requests of towed system.(2) On basis of complete hydrodynamic model of towed system, lift force and drag force of controllable wings are analyzed to choose the right aerofoil.The variable range of angle of attack has been achieved through fluid experiments.(3) To detect the weak signal of cholophyll fluorescence, low power consumed optical electronics are chosen, and turbidity can be also detected with the same instrument. Multi-channel nutrient sensor was intergrated to consist the ecological monitoring group of real time, quasi- synchronization and high speed sampling (1 Hz).(4)Through the lake test,system design was improved. And in the sea trial, 200m depth profiling of muitiple factors was archieved with high accuracy synchronization. Every design of system has been approved.Especially, the ratio of cable length to depth reaches 1.2 to 1.5, which shows the system has great hydrodynamics. During the sea experiment, a strong horizontal compensation of thermohaline gradients in the...