3/16/2023 0 Comments Degrees of freedomeHowever, examples of the trajectory simulations using the 6DOF equations are presented using existing low and high-Reynolds number force and moment correlations. Force and moment relationships specific to the Sensor Fish body are currently not available. Transformations between the body-fixed and interial reference frames are performed using a formulation based on quaternions. The equations of motion are written in the body-fixed frame of reference. Some simplifications are made by considering the Sensor Fish device to be a rigid, axisymmetric body. In this report, we describe a fairly general formulation for the coordinate systems, equations of motion, force and moment relationships necessary to simulate the 6DOF movement of an underwater body. Before the 6DOF Sensor Fish device can be developed and deployed, governing equations of motion must be developed in order to understand the design implications of instrument selection and placement within the body of the device. Rate gyros will be added to the new six degree of freedom (6DOF) device so that it will be possible to observe the six linear and angular accelerations of the Sensor Fish as it passes the dam. Pacific Northwest National Laboratory (PNNL) is in the process of redesigning more ยป the current 3DOF Sensor Fish device package to improve its field performance. The most recent Sensor Fish design, the three degree of freedom (3DOF) device, has been used successfully to characterize the environment fish experience when passing through turbines, in spill, or in engineered fish bypass facilities at dams. Since its initial development in 1997, the Sensor Fish has undergone numerous design changes to improve its function and extend the range of its use. The Sensor Fish device is being used at Northwest hydropower projects to better understand the conditions fish experience during passage through hydroturbines and other dam bypass alternatives. The study indicates that a 6DOF analysis will yield information about a spread of possible trajectories, while using an average drag coefficient can only represent the most likely = , The fragment trajectory distribution and steady tumbling rate is explored. The results of the example fragment indicate that the distance traveled in the early ight (from 2.5 km/s until decreasing down to 1 km/s) varies widely depending on the initial orientations. The simulation procedure is then demonstrated for an example fragment. The supersonic flow simulations are tested for simple geometries and show good agreement with literature values. Second, this the aerodynamic coefficient database is imported into a 6DOF rigid body dynamics solver in order to compute the resulting trajectories. The forces and moments are normalized and tabulated in a database. First, aerodynamic forces and moments as functions of orientation are computed using the SIERRA/Aero supersonic flow solver. In this report a process using existing technologies at Sandia National Laboratories (SNL) to simulate the six degrees-of-freedom (6DOF) trajectories of explosive fragments is described and tested.
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