ISALE3D

From AMCGMedia

An oblique collision of two planetesimals at 5 km/s, simulated using iSALE3D.

iSALE3D

The vast majority of our current understanding of impact is derived from models and experiments where the impactor strikes perpendicular to the target surface. In reality, such events are extremely unlikely to occur; the most common impact angle is 45° to the target plane and over 90% of all impacts are oblique (<70°). It is therefore vital to understand oblique impact processes. iSALE3D is a new tool for studying oblique impacts, based on iSALE.

Technology

iSALE3D (impact-SALE3D) is a multi-material extension of the SALE3D hydrocode (Simplified Arbitrary Lagrangian Eulerian) and iSALE. This software has been developed and optimised specifically for simulating planetary-scale impact processes by Dirk Elbeshausen, Dr. Gareth Collins and Dr. Kai Wuennemann.

Features

• Regular structured mesh
• Explicit finite-difference solution algorithm
• Arbitrary Lagrangian Eulerian material description
• Artificial viscosity for shock capturing
• Multi-material advection scheme with PLIC/SLIC interface reconstruction
• ANEOS and Tillotson equation of state routines
• Fast and efficient output data read/write/compression algorithms
• Parallelisation using MPI (Message Passing Interface) libraries
• Custom Visualisation software (VIMoD)

Validation

iSALE3D is in the process of being validated against laboratory experiments and is being tested along with other hydrocodes as part of the Impact Hydrocode Benchmark and Validation Project. Model development and validation are ongoing, funded through separate projects, to ensure that iSALE3D is a state-of-the-art tool in the study of impacts throughout the solar system.

Applications

iSALE3D is being used to study the effect of impact angle on:

• Crater formation
• Collision of small bodies
• Crater formation in high strength targets

Developers

iSALE is actively developed by AMCG members

• Dr. Gareth Collins
• Tom Davison
• Ross Potter

and by our partner research group at the Museum fur Naturkunde, Unversitat de Berlin

• Dr. Kai Wuennemann
• Dirk Elbeshausen

iSALE3D owes much of its sophistication to the pioneering early development of SALE by

• Dr. Boris Ivanov
• Prof. Jay Melosh

Publications

1. Elbeshausen, D., Wünnemann, K. and Collins, G.S. 2008. Crater Scaling for Oblique Impacts in Frictional Targets: Insight from 3D Hydrocode Modelling. Lunar and Planetary Science XXXIX, LPI Contribution No. 1391, p.1795
2. Wünnemann, K., Collins, G.S. and Elbeshausen, D. 2008. Limitations of Point-Source Analogy for Meteorite Impact and Implications to Crater-scaling, Large Meteorite Impacts and Planetary Evolution IV. LPI Contribution No. 1423, paper id. 3076
3. Collins G.S., Morgan J.V., Wünnemann K., Elbeshausen D., Gulick S., Barton P. and Christeson G. (2007) Is the Chixculub crater asymmetry due to target asymmetry or oblique impact? Insight from numerical modelling. Eos Trans. AGU, 88(52), Fall Meet. Suppl., Abstract U22A-02.
4. Wünnemann K., Elbeshausen D. and Collins G.S. (2007) The effect of impact angle on the formation of meteorite impact craters: Insight from 3D numerical modeling. Eos Trans. AGU, 88(52), Fall Meet. Suppl., Abstract U22A-01.
5. Elbeshausen D., Wünnemann K. and Collins G. S. (2007) Three-dimensional numerical modeling of oblique impact processes: Scaling of cratering efficiency. LPSC XXXVIII, #1952.

Installation instructions

Some specific iSALE3D installation instructions may be found here.