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Birdstrike simulation pre and post impact
Smoothed Particle Hydrodynamics (SPH) reduces the time to create a mesh, because gaps and overlapping surfaces do not prevent mesh generation.
The generation and modification of finite element and control volume meshes can take a significant proportion of the time available in a modelling project. Reducing the time required to build meshes would improve the turnaround time and reduce the cost of solutions. One important accelerator would be eliminating the need to modify CAD geometries to make them suitable for model generation.
Solution adaptivity through mesh refinement and coarsening is a desirable feature in many analyses because it enables important features to be resolved accurately. Traditionally this has required the regeneration of meshes based on preceeding simulations. SPH enables the creation and deletion of particles as dictated by the solution, and there is no need to remesh because there is no connectivity between particles.
Smoothed Particle Hydrodynamics (SPH) is a Lagrangian meshless method for the solution of partial differential equations. Spatial discretisation is achieved via a distribution of interpolation points (pseudo-particles) that place no requirement on connectivity. This provides a mechanism for reducing the model set up time and is naturally suited to problems involving complex free surface behaviour, fracture or penetration. SPH tracks the movement of material and can therefore model problems involving history dependent material properties, such as resin cure.
An SPH code has been developed that can model a range of fluid flow problems involving free surfaces. The focus has been the development of a non-isothermal RTM simulation capability in 3D, and the code has been validated against a range of test cases. Additional developments have included the modelling of material strength that enables the solution of problems involving fluid-structure interaction, and a parallel version of the code has been developed.
Further developments are required to fully exploit the potential benefits of the meshless methodology. These relate to pre & post processing, variable particle resolution and improved parallel performance.
Application Areas
The method is particularly suited to fluid and structural dynamic problems involving free surfaces, fragmentation and complex physics.
Applications of interest to BAE Systems include:
- Manufacturing operations involving mould filling
- Hydrodynamic ram and bird strike
- Naval applications involving free surfaces
- Tank Sloshing
- Super-cavitation
