[CIG-LONG] Extension - Compressible Layer in Gale

[atyl0789 at uni.sydney.edu.au]

G'day All,

Thanks very much for the advice so far, it has been very helpful :)

>The only real problem you may have is from having such a deformed
>grid.  For runs with an air layer, I would recommend making the top of
>the simulation fixed.  Air will flow in and out of the simulation, but
>the mesh will stay the same.  And, as Louis Moresi said, it does not
>really matter what the air does, since it really only acts as a
>stabilization term.

I apologise if this is a silly question, but how do I make the top of the simulation fixed/free slip? I initially thought that I would just set vy=0 at the top and change WrapTop=true to false, however someone suggested that I instead just set the top boundary to be static. I'm actually not clear on what the difference between these approaches is, so any explanation would be much appreciated :)

>In HydrostaticTerm, there is a variable 'height'.  Set that to the top
>of your material layer, not the top of the simulation.

That makes a lot of sense, I can't believe I didn't think of that! However I wonder whether when the model extends, this height would eventually become incorrect and I would end up with the hydrostatic term in the air layer? Would this be an issue at all?

Thanks again for the help!

Cheers,
Aaron Tyler