Multiple Body Dynamics Research Articles

Development of a Modularized Virtual Flight Simulator based on Multiple Discipline Coupled Method

The problem of aircraft control involves multiple subjects and has always been extremely complicated in mechanics modelling. Virtual flight simulation was put forward in order to reduce the cost of full-scale airplane flying test and wind tunnel experiment. A typical virtual flight simulator includes a computational fluid dynamics (CFD) solver, a structure dynamics (FD) function, and a flight controller. However, existed virtual flight solver usually ignores the universal modelling of dynamics for complex aircraft configuration and the modularization of CFD, FD and flight controller module, which makes it very inconvenient for many in-house virtual flight codes for engineering application and commercial software development. A new framework of virtual flight simulation platform is established with a parallel Reynolds Averaged Navier-Stokes (RANS) solver, a structured moving overlapping grid function, a generic multiple body dynamics (MBD) solver, and a plug-in type flight controller platform. A universal data exchange interface between MBD and flight controller is presented. An X-wing missile flying forward and pitching-up maneuvering validation case is conducted with the current virtual flight simulator, the result is compared with Matlab Simulink solver based on steady aerodynamic database and good agreement is obtained.

Fluid–structure interaction simulation based on immersed boundary-lattice Boltzmann flux solver and absolute nodal coordinate formula

Large deformation fluid–structure interaction (FSI) is a typical nonlinear problem in aero elastics. Engineering applications can be found in aviation, marine engineering, and bio-fluid mechanics. A three-dimensional (3D) parallel FSI solver based on an immersed boundary-lattice Boltzmann flux solver (IB-LBFS) and absolute nodal coordinate formula (ANCF) is established. The computational efficiency of the parallel IB-LBFS with moving boundaries is improved by several acceleration techniques, including Euler–Lagrangian interpolation matrix parallel assembling and sparse matrix solving methods. Structure dynamics simulation discretized in high-order ANCF elements distinctly reduces the number of finite elements compared with the standard finite element method. A multiple body dynamics (MBD) solver including a rigid body, ANCF cable elements, and ANCF plate elements is developed. The IB-LBFS, MBD solver, and coupled FSI solver are tested by the corresponding validation examples. A framework of solving 3D FSI problems of complex multiple flexible structures with large deformation in incompressible flow is presented. An implicit boundary condition enforced method is applied to achieve a strong coupling approach. For application demonstration, the inflation process of several types of parachute systems is simulated in which different Young’s moduli of the parachute canopy are considered. The interaction between dynamic deformation and an unsteady vortex is obtained and discussed.

Dynamics of Multiple Bodies in a Corotation Resonance: Conserved Quantities and Relevance to Ring Arcs

Abstract The interactions among objects in a mean motion resonance are important for the orbital evolution of satellites and rings, especially Saturn’s ring arcs and associated moons. In this work, we examine interactions among massive bodies in the same corotation eccentricity resonance site that affect the orbital evolution of those bodies using numerical simulations. During these simulations, the bodies exchange angular momentum and energy during close encounters, altering their orbits. This energy exchange, however, does not mean that one body necessarily moves closer to exact corotation when the other moves away from it. Indeed, if one object moves toward one of these sites, the other object is equally likely to move toward or away from it. This happens because the timescale of these close encounters is short compared to the synodic period between these particles and the secondary mass (i.e., the timescale where corotation sites can be treated as potential maxima). Because the timescale of a gravitational encounter is comparable to the timescale of a collision, we could expect energy to be exchanged in a similar way for collisional interactions. In that case, these findings could be relevant for denser systems like the arcs in Neptune’s Adams ring and how they can be maintained in the face of frequent inelastic collisions.