In order to reduce the hydrodynamic and structural influences on the detection accuracy especially in the very-lowfrequency range, some vibration restraint methods are raised, which are the wrapped fairing improvement...In order to reduce the hydrodynamic and structural influences on the detection accuracy especially in the very-lowfrequency range, some vibration restraint methods are raised, which are the wrapped fairing improvement, the floating body shape improvement and the cable vibration reduction treatment. Through the improvement analysis and experimental comparison, the final treatments are proposed, namely the multilayer wrapped fairing structure with composite materials, the floating body with NACA0024 airfoil section and X-shape tail spoiler, as well as the brush cable. The sea test is carried out to evaluate the vibration restraint effect. Through comparison of the responses to the ocean ambient noise and the direction of arrival(DOA) estimations with the same underwater transmitting transducer, the results indicate that the horizontal floating platform with vibration restraint treatment has obvious flow resisting effect especially in low frequency range and more accurate DOA estimation.展开更多
Elastic reverse-time migration can effectively deal with multicomponent seismic data in which the imaging condition based on energy norm can extract the scalar-imaging result from multicomponent data.However,the energ...Elastic reverse-time migration can effectively deal with multicomponent seismic data in which the imaging condition based on energy norm can extract the scalar-imaging result from multicomponent data.However,the energy cross-correlation imaging condition characterized by particle velocity and stress suffers from the problem of overdependence on the background elastic parameters.Therefore,we characterize the elastic-wave energy using the energy-flow vector,which is equal to the energy density,without background elastic parameters.According to the source and receiver wave fields,we propose an imaging energyflow vector and an elastic-wave energy imaging condition.Under the assumption of a planewave solution,the backscattering suppression is verified.The numerical simulations show that the elastic-energy imaging condition can obtain the energy image without backscattering.Compared with the cross-correlation imaging conditions in a vector-based wave field,the proposed imaging condition can eliminate the dependence on the background elastic parameters and effectively process seabed multicomponent data,which are conducive to further providing an interpretation of marine geological structures.展开更多
基金financially supported by the Key Research and Development Plan (Public) Project of Shandong Province (Grant No.2019GHY112042)the International Science and Technology Cooperation Project of Shandong Academy of Sciences (Grant No. 2019GHZD01)。
文摘In order to reduce the hydrodynamic and structural influences on the detection accuracy especially in the very-lowfrequency range, some vibration restraint methods are raised, which are the wrapped fairing improvement, the floating body shape improvement and the cable vibration reduction treatment. Through the improvement analysis and experimental comparison, the final treatments are proposed, namely the multilayer wrapped fairing structure with composite materials, the floating body with NACA0024 airfoil section and X-shape tail spoiler, as well as the brush cable. The sea test is carried out to evaluate the vibration restraint effect. Through comparison of the responses to the ocean ambient noise and the direction of arrival(DOA) estimations with the same underwater transmitting transducer, the results indicate that the horizontal floating platform with vibration restraint treatment has obvious flow resisting effect especially in low frequency range and more accurate DOA estimation.
基金supported by the National Nature Science Foundation of China(No.61801275)Shangdong Provincial Natural Science Foundation(No.ZR2018BF002)+2 种基金China Postdoctoral Science Foundation(No.2017M622242)Basic Research Projects of Science,Education and Industry Integration Pilot Project of Qilu University of Technology(2022PX082)Qingdao Applied Research Projects.
文摘Elastic reverse-time migration can effectively deal with multicomponent seismic data in which the imaging condition based on energy norm can extract the scalar-imaging result from multicomponent data.However,the energy cross-correlation imaging condition characterized by particle velocity and stress suffers from the problem of overdependence on the background elastic parameters.Therefore,we characterize the elastic-wave energy using the energy-flow vector,which is equal to the energy density,without background elastic parameters.According to the source and receiver wave fields,we propose an imaging energyflow vector and an elastic-wave energy imaging condition.Under the assumption of a planewave solution,the backscattering suppression is verified.The numerical simulations show that the elastic-energy imaging condition can obtain the energy image without backscattering.Compared with the cross-correlation imaging conditions in a vector-based wave field,the proposed imaging condition can eliminate the dependence on the background elastic parameters and effectively process seabed multicomponent data,which are conducive to further providing an interpretation of marine geological structures.
