Sister blog of Physicists of the Caribbean. Shorter, more focused posts specialising in astronomy and data visualisation.

Tuesday, 29 July 2014

A first test of ram pressure stripping


Nothing to do with morally dubious barnyard antics, RPS is simply gas stripping from one body (in this case a cold, dense disc) moving through a medium (which in this case is very hot and very low density). As the dense gas moves, "ram" pressure from the medium builds up, which can be strong enough to push the dense gas out of its happy stable orbit.

Here the medium is very very thin, and although it's a million Kelvin and moving at 1,000 km/s, it's only strong enough to push the outermost (lowest density) gas out of the disc. The colours are logarithmic, the long cone of gas which develops is fairly pathetic compared to the gas which remains in the disc.

This one is really jumping the gun - the "stable gas disc" has its gravity modelled purely by a fixed analytic potential (no self gravity) and no stars, let alone star formation. But it's a taste of things to come.

5 comments:

  1. Rhys Taylor  Can I run the FLASH code on a Linux machine with i5 and 4G memory?

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  2. Why do a get the feeling modeling of comets won't be far behind :)

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  3. Akira Bergman Yes, but you won't be able to run very high resolution simulations with it. This was run on an i7 with 16GB, but for our science-class runs we'll be using a 350 core computer cluster.

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  4. How long did this take to run on the i7?

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  5. Daniel Taylor Initially it was taking > 3 days. Then I realised I had the hot gas set to a density 100 million times lower than the cold gas, which causes problems for the adaptive mesh refinement. Whacking up the density a few orders of magnitude and it runs in about an hour. :)

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