| Ocean turbulence is a continuous irregular flow,which contains many vortices of different scales.Turbulence is the main form of ocean kinetic energy dissipation and the driving force of ocean macroscopic phenomena.It is of great significance to human activities such as climate,deep-sea circulation,and tide forecasting.The driving force of transport for energy and material in the deep ocean is turbulent mixing,which is crucial to understand the oceanic various scale phenomena and energy cascade.Obtaining accurate turbulence data is of great significance for studying the macroscopic motion and physical mechanism of the sea area.The active range of ocean turbulence is the whole sea depth,extending from the surface to the bottom of the sea.However,due to the difficult control of the instrument at the bottom and the high cost of equipment,it is currently impossible to observe the seabed boundary layer.At present,most of the turbulence observations merely explore the characteristics of the single vertical path with depth less than 1000 m.The key to a transparent ocean system is to achieve6,000-meter deep turbulence observation in our country.Traditional turbulence sensors can only achieve one-dimensional observation,and they are short of directivity characteristics for turbulent structures in complex three-dimensional flow field.Moreover,in order to realize vector observation,two one-dimensional sensors were arranged orthogonally in the past.Such observation methods are non-single-point observation and have low resolution.Therefore,it is urgent to develop a two-dimensional vector turbulence sensor.Regarding the generation process of ocean turbulence,it involves a dynamic process from “10-meter-scale” to “meter-scale” and then to “centimeter-scale”.The turning process of “meter-scale” is the key to the formation of turbulence.This "meter-scale" flip structure has multi-point correlation.Therefore,a complete description of the turbulence generation process requires "meter-scale" observations with horizontal multipoint correlation.The data of horizontal coherence and the temporal evolution on meter-scale boundary turbulence are lacked.In order to realize multi-sectional explicit observation of deep ocean and improve the turbulence understanding of critical ocean-air and bottom boundary layer,it is urgent requirement to develop novel turbulence sensing mechanism and instrument.This paper aimed to propose a high spatial resolution vector turbulence sensor based on MEMS technology and develop low-cost matric turbulence observing instrument on the full depth section of the ocean.Inspired by cluster-bomb,we will achieve the observation of full depth section of the ocean up to 6000 m.First,the matrix type profile observation instrument straddles the upper mixed layer,and realizes the separation of the sub-profilers at the relatively smooth movement of the ocean currents at a depth of 500 meters.The sub-profilers are released synchronously,and submerged in a matrix type,which can effectively guarantee the independent operation attitude of the sub-profilers and the quality of the horizontal synchronous observation data.When the sub-profiler crosses the seafloor boundary layer,reaches the near seafloor position and then floats up and recovered,it can accurately measure the turbulence structure of the seafloor boundary layer.When recovering sub-profiles,ocean wave energy are used to convert to electricity to power the inner sensors.In addition,the operating expense of instrument would be reduced,owing to reliable data retrieving and instrument recycling technique.Eventually,researches on turbulent mixing and evolution of boundary layer would be performed on the basis of this kind of matric sectional observation.With the instrument developed successfully,we can achieve the synchronized time and space,three-dimensional integrated observation of turbulent mixing on the full depth section of the ocean.We can expand the space-time coverage and monitoring scale of ocean observation,and improve the "transparent ocean" scientific cognition.The research data can optimize the detailed study of coherent structure and multi-scale coupling,which will help build physical and mathematical model of turbulent mixing in the deep sea.The fulfillment of this project will break through the limitations of existing marine observations and enhance the deep ocean research capacity.This is of great significance to achieve the predictability of the ocean environment,and profound development of sea observation,monitoring and research.The main points of this paper are as follows.1.Turbulence mixed matrix observation instrument is developed for all sea depth inspired by cluster-bomb,which adopts the mechanical structure of three-disk release combined with electromagnet control release scheme,breaking through the key technology of synchronous separation control of the instrument in deep-sea high-pressure environment.2.A MEMS two-dimensional turbulence sensor is proposed,which is composed of biomimetic cilia and four beam microstructure.Parameters of the sensor are designed after simulation analysis.The resonance frequency of the sensor is tested.A turbulence test platform is built,and the sensor is compared and calibrated with PNS.It is verified that the MEMS turbulence sensor is vectorial and can withstand pressure of 40 MPa.3.A scheme to harvest ocean wave energy to supply power for the instruments before recovery.Based on the principle of friction electrification and electromagnetic induction,two kinds of hybrid generators with different structures are proposed.The box like triboelectricelectromagnetic hybrid generator can harvest wave energy in two-dimensional direction by using complementary mechanism.The maximum output power of electromagnetic part and triboelectric part is 14.9m W and 0.08 m W,respectively.A self-powered wireless sensor system is built.4.The basic function of the matrix instrument has been verified and the turbulence signal has been measured. |
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