Download - AUTODYN Euler Blast Solver

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February 27, 2009Inventory #002665

Chapter 6

Euler Blast (Ideal Gas) Solver

ANSYS AUTODYN




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




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




Training Manual

Initial material locations

Final material locations

Final pressure contoursFinal pressure profile

1D Spherically Diverging Detonation Wave(AUTODYN 2D Multi-material Euler Solver)





Training Manual

Urban Blast





Training ManualExample: Explosion in a Building




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




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




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




Training Manual

3D

1D (spherical)

2D (axial)

Multi-dimensional Remapping• Accuracy can be maximized, by remapping blast solutions from 1D to 2D to 3D




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

Download - AUTODYN Euler Blast Solver

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