autodyn euler blast solver
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6-1ANSYS, Inc. Proprietary© 2009 ANSYS, Inc. All rights reserved.
February 27, 2009Inventory #002665
Chapter 6
Euler Blast (Ideal Gas) Solver
ANSYS AUTODYN
Euler Blast (Ideal Gas) Solver
6-2ANSYS, Inc. Proprietary© 2009 ANSYS, Inc. All rights reserved.
February 27, 2009Inventory #002665
Training Manual
• Efficient and accurate solution of blast problems– Multi-dimensional implementation of the explicit FCT (Flux Corrected Transport)
formulation of Boris & Book
• Rectangular cells aligned with coordinate directions– Grid can be graded
• Hydrodynamic inviscid flow– Single ideal gas per Part
• No void regions• Unused regions can model rigid structures
• In-flow and Out-flow boundaries
• Joined Parts
• Coupling to Lagrange solvers
• Extensive Remapping options
Overview
Euler Blast (Ideal Gas) Solver
6-3ANSYS, Inc. Proprietary© 2009 ANSYS, Inc. All rights reserved.
February 27, 2009Inventory #002665
Training Manual
• Detonation and expansion of 1000kg charge initially modelled as a 1D spherical calculation using the AUTODYN 2D multi-material Euler solver
– Models the detonation of the explosive accurately
– Uses a very high resolution mesh
• Results are remapped into an AUTODYN 3D Ideal Gas Solver mesh as initial conditions
– At large expansions, detonation products behave like air, so HE and Air can be combined into a single material (Air)
• Allows assessment of the effects of building confinement on the propagation of blast waves
Example: Urban Blast
Euler Blast (Ideal Gas) Solver
6-4ANSYS, Inc. Proprietary© 2009 ANSYS, Inc. All rights reserved.
February 27, 2009Inventory #002665
Training Manual
Initial material locations
Final material locations
Final pressure contoursFinal pressure profile
1D Spherically Diverging Detonation Wave(AUTODYN 2D Multi-material Euler Solver)
Example: Urban Blast
Euler Blast (Ideal Gas) Solver
6-5ANSYS, Inc. Proprietary© 2009 ANSYS, Inc. All rights reserved.
February 27, 2009Inventory #002665
Training Manual
Urban Blast
Example: Urban Blast
Euler Blast (Ideal Gas) Solver
6-6ANSYS, Inc. Proprietary© 2009 ANSYS, Inc. All rights reserved.
February 27, 2009Inventory #002665
Training ManualExample: Explosion in a Building
Euler Blast (Ideal Gas) Solver
6-7ANSYS, Inc. Proprietary© 2009 ANSYS, Inc. All rights reserved.
February 27, 2009Inventory #002665
Training ManualExample: Explosion in a Building
Euler Blast (Ideal Gas) Solver
6-8ANSYS, Inc. Proprietary© 2009 ANSYS, Inc. All rights reserved.
February 27, 2009Inventory #002665
Training Manual
• Refine lets you refine a rectilinear 3D mesh by subdividing existing cells into multiple cells
– You specify the number of subdivision to be used in the I, J and K directions
– Primarily used for Euler FCT meshes, but can also be used for Lagrange, ALE and MM Euler
• Block Remap performs a fast remap from a refined mesh to the unrefined mesh
Refine and Block Remap
Before Refinement After Refinement
Euler Blast (Ideal Gas) Solver
6-9ANSYS, Inc. Proprietary© 2009 ANSYS, Inc. All rights reserved.
February 27, 2009Inventory #002665
Training Manual
Data source: Risk Management Solutions and Sanborn Map Co.
Fill Block
• Imports a meshed and filled Euler Ideal Gas Solver Part from an external file
– External file includes:
• The (I,J,K) range spanned by the data
• The (X,Y,Z) dimensions for a single cell (all cells are the same size)
• A flag for each cell:
0 – Cell is part of a structure (unused)
1 – Cell is filled with air
2 – Cell is filled with air and assigned a gauge
Euler Blast (Ideal Gas) Solver
6-10ANSYS, Inc. Proprietary© 2009 ANSYS, Inc. All rights reserved.
February 27, 2009Inventory #002665
Training ManualStaged Blast Calculations• Fill Block, Refine and Block Remap can be used together to perform large range
staged blast calculations
Stage 1 Stage 2 Stage 3
Euler Blast (Ideal Gas) Solver
6-11ANSYS, Inc. Proprietary© 2009 ANSYS, Inc. All rights reserved.
February 27, 2009Inventory #002665
Training Manual
3D
1D (spherical)
2D (axial)
Multi-dimensional Remapping• Accuracy can be maximized, by remapping blast solutions from 1D to 2D to 3D
Euler Blast (Ideal Gas) Solver
6-12ANSYS, Inc. Proprietary© 2009 ANSYS, Inc. All rights reserved.
February 27, 2009Inventory #002665
Training ManualWorkshop 5: Urban BlastGoal:
Model a Explosive blast in an urban environment
Procedure:
Start AUTODYN standalone
Set up and solve a problem using 2D Axial Symmetry to model the initial spherical blast
Set up a 3D problem to model the urban area of the blast
Remap the results from the 2D model into the 3D model as initial conditions
Run the 3D solve
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