Abstract. During the cruise process of prionace glauca, its pectoral fins play an important role in keeping balance and stability of its body. The research on the fluid-solid coupling of prionace glauca pectoral fins is of important value to optimizing the design of the AUV and other marine engineering equipment. This paper studies the deformation shrinkage process of coupling between prionace glauca pectoral fins and the flow through the physical field technology of COMSOL fluid-solid coupling, and carries out the secondary development of COMSOL simulation interface to create App, and builds an intuitive user interface which is suitable for the fluid-solid coupling research of prionace glauca pectoral fins. The research result can improve the ability of modelling and post-processing, avoid the user input errors and focus on the output at the same time. The secondary development in this paper provides an important reference for COMSOL in practical engineering application.
Prionace glauca has high efficiency and long-distance cruising mode, its pectoral fins play an important role in keeping balance and stability. Selecting the pectoral fins as a breakthrough to conduct related research has an important value for the optimization design of autonomous underwater vehicle (AUV) and other marine equipment. Through numerical description, the establishment of a two-dimensional fine pectoral model and finite element calculations in the unsteady fluid, we found the variation features of Karman Vortex Street of flexible pectoral fins in the unsteady flow. Further comparative analysis of vortex characteristics of Prionace glauca pectoral fins models with different shapes and under the same boundary conditions, the study found that the streamlined samples of pectoral fins help reduce the impact of water flow and improve the stability of Prionace glauca during swimming in the flow field, which provides a good foundation for structural optimization design and other related applications of AUV.
This paper introduces a new measurement system for measuring the position of a projectile within a rapid fire electromagnetic launching system. The measurement system contains both non-contact laser shading and metal fiber contact measurement devices. Two projectiles are placed in the rapid fire electromagnetic launch bore, one in the main accelerating segment and the other in the pre-loading segment. The projectile placed in the main accelerating segment should be shot first, and then the other is loaded into the main segment from the pre-loading segment. The main driving current (I-main) can only be discharged again when the second projectile has arrived at the key position (the projectile position corresponds to the discharging time) in the main accelerating segment. So, it is important to be able to detect when the second projectile arrives at the key position in the main accelerating segment. The B-dot probe is the most widely used system for detecting the position of the projectile in the electromagnetic launch bore. However, the B-dot signal is affected by the driving current amplitude and the projectile velocity. There is no current in the main accelerating segment when the second projectile moves into this segment in rapid fire mode, so the B-dot signal for detecting the key position is invalid. Due to the presence of a high-intensity magnetic field, a high current, a high-temperature aluminum attachment, smoke and strong vibrations, it is very difficult to detect the projectile position in the bore accurately. So, other measurements need to be researched and developed in order to achieve high reliability. A measurement system based on a laser (non-contact) and metal fibers (contact) has been designed, and the integrated output signal based on this detector is described in the following paper.
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