A Patch NAH method based on HELS( helmholtz equation least-squares) algorithm is proposed for the measurement requirement of underwater large structures. This method chooses HELS algorithm to approximate the sound fie...A Patch NAH method based on HELS( helmholtz equation least-squares) algorithm is proposed for the measurement requirement of underwater large structures. This method chooses HELS algorithm to approximate the sound field completely,and calculates the sound field data outside the measurement region to enlarge the measurement aperture. It can reconstruct the sound field by the measurement data and the extrapolation data,through the reconstruction result it can be researched for the minimum measurement surface and the range of the extrapolation data in application. The paper analyzes the effect from the different measurement surfaces and different extrapolation ranges to the extrapolation data by simulations,and compares these reconstructed results with the conventional algorithm results. The simulation results indicate that the method can simplify the holographic measuring system,save the cost of the project and improve the accuracy of the sound field reconstruction,which can be effectively used for measuring and analyzing the underwater large structures.展开更多
Since the first laser was invented,the pursuit of high-energy lasers(HELs)has always been enthusiastic.The first revolution of HELs was pushed by the fusion of laser and aerospace in the 1960s,with the chemical rocket...Since the first laser was invented,the pursuit of high-energy lasers(HELs)has always been enthusiastic.The first revolution of HELs was pushed by the fusion of laser and aerospace in the 1960s,with the chemical rocket engines giving fresh impetus to the birth of gas flow and chemical lasers,which finally turned megawatt lasers from dream into reality.Nowadays,the development of HELs has entered the age of electricity as well as the rocket engines.The properties of current electric rocket engines are highly consistent with HELs’goals,including electrical driving,effective heat dissipation,little medium consumption and extremely light weight and size,which inspired a second fusion of laser and aerospace and motivated the exploration for potential HELs.As an exploratory attempt,a new configuration of diode pumped metastable rare gas laser was demonstrated,with the gain generator resembling an electric rocket-engine for improved power scaling ability.展开更多
基金Sponsored by the Scientific Research Fund of Heilongjiang Provincial Education Department(Grant No.12541132)
文摘A Patch NAH method based on HELS( helmholtz equation least-squares) algorithm is proposed for the measurement requirement of underwater large structures. This method chooses HELS algorithm to approximate the sound field completely,and calculates the sound field data outside the measurement region to enlarge the measurement aperture. It can reconstruct the sound field by the measurement data and the extrapolation data,through the reconstruction result it can be researched for the minimum measurement surface and the range of the extrapolation data in application. The paper analyzes the effect from the different measurement surfaces and different extrapolation ranges to the extrapolation data by simulations,and compares these reconstructed results with the conventional algorithm results. The simulation results indicate that the method can simplify the holographic measuring system,save the cost of the project and improve the accuracy of the sound field reconstruction,which can be effectively used for measuring and analyzing the underwater large structures.
文摘Since the first laser was invented,the pursuit of high-energy lasers(HELs)has always been enthusiastic.The first revolution of HELs was pushed by the fusion of laser and aerospace in the 1960s,with the chemical rocket engines giving fresh impetus to the birth of gas flow and chemical lasers,which finally turned megawatt lasers from dream into reality.Nowadays,the development of HELs has entered the age of electricity as well as the rocket engines.The properties of current electric rocket engines are highly consistent with HELs’goals,including electrical driving,effective heat dissipation,little medium consumption and extremely light weight and size,which inspired a second fusion of laser and aerospace and motivated the exploration for potential HELs.As an exploratory attempt,a new configuration of diode pumped metastable rare gas laser was demonstrated,with the gain generator resembling an electric rocket-engine for improved power scaling ability.
