Abstract: An improved modal decomposition method applicable to the analysis and reconstruction of the measured flow fields of internal solitary waves includes the following steps: S1. generating internal solitary waves and measuring a two-dimensional flow field sequence during the interaction of the internal solitary waves with the terrain; S2. extracting a target information from the two-dimensional flow field sequence and obtaining a flow field snapshot; S3. stitching the snapshots into a snapshot matrix in time order; S4. plotting the information density curve; S5. normalizing the information density curve and determining split points; S6. setting the snapshot matrix between two adjacent split points as a linear evolutionary characteristic stage; and S7. performing dynamic mode decomposition on the linear evolutionary characteristic stages.

Abstract: A test device suitable for acceleratory oblique water entry of a wedge has a frame, a water tank placed below the frame, an accelerator installed above the frame, an obliquing device connected to the frame, a wedge connected to the obliuqing device and an observation system. The frame is provided with vertical slide rails and a transverse slide rail. The accelerator mainly includes an air cylinder and an air compressor. The wedge is a flexible wedge or a rigid wedge. The observation system includes a pressure sensor, a strain sensor, a velocity sensor, an acceleration sensor and a particle image velocimetry device. The repeatability of the test process can be ensured by controlling the output pressure of the air cylinder.

Abstract: The present disclosure provides a parameter design and numerical simulation method for jet trencher nozzle, comprising the following steps: S1. designing parameters of nozzle; S2. selecting the parameters of nozzle; S3. establishing a geometric model; S4. setting boundary conditions and delineating grids; S5. performing numerical simulation using Flow-3D; and S6. performing results processing and analysis. According to the present invention, the whole process of nozzle flushing and ground breaking can be simulated, the size of the cross-section of the flushing trench is measured, and by analyzing the obtained result, the reasonability of nozzle radius parameter design can be verified, and a certain reference is provided for design of inclination angle parameters.

Abstract: An improved modal decomposition method applicable to the analysis and reconstruction of the measured flow fields of internal solitary waves includes the following steps: S1. generating internal solitary waves and measuring a two-dimensional flow field sequence during the interaction of the internal solitary waves with the terrain; S2. extracting a target information from the two-dimensional flow field sequence and obtaining a flow field snapshot; S3. stitching the snapshots into a snapshot matrix in time order; S4. plotting the information density curve; S5. normalizing the information density curve and determining split points; S6. setting the snapshot matrix between two adjacent split points as a linear evolutionary characteristic stage; and S7. performing dynamic mode decomposition on the linear evolutionary characteristic stages.

Abstract: A test device suitable for acceleratory oblique water entry of a wedge has a frame, a water tank placed below the frame, an accelerator installed above the frame, an obliquing device connected to the frame, a wedge connected to the obliuqing device and an observation system. The frame is provided with vertical slide rails and a transverse slide rail. The accelerator mainly includes an air cylinder and an air compressor. The wedge is a flexible wedge or a rigid wedge. The observation system includes a pressure sensor, a strain sensor, a velocity sensor, an acceleration sensor and a particle image velocimetry device. The repeatability of the test process can be ensured by controlling the output pressure of the air cylinder.

Abstract: The present disclosure provides a parameter design and numerical simulation method for jet trencher nozzle, comprising the following steps: S1. designing parameters of nozzle; S2. selecting the parameters of nozzle; S3. establishing a geometric model; S4. setting boundary conditions and delineating grids; S5. performing numerical simulation using Flow-3D; and S6. performing results processing and analysis. According to the present invention, the whole process of nozzle flushing and ground breaking can be simulated, the size of the cross-section of the flushing trench is measured, and by analyzing the obtained result, the reasonability of nozzle radius parameter design can be verified, and a certain reference is provided for design of inclination angle parameters.