[aspect-devel] velocity RMS

[Timo Heister]

Hi Cedric,

5 cm/s are about 1.6e6 m/year, so I think something with the units
does not add up correctly for you. Are you setting "set Use years in
output instead of seconds = false"?

Oh, and what are the boundary conditions at the top and bottom? It
looks like there are some artifacts on the top boundary...

On Fri, Dec 14, 2012 at 6:27 AM, Thieulot, dr. C. (Cedric)
<c.thieulot at uu.nl> wrote:
>
> Hi,
> I am trying to run a model where I impose on the right boundary an in/out-flux given by a cosine function. The integral of the flux on the boundary is therefore zero.
> Here's what the input file looks like:
>
> [...]
> set Prescribed velocity boundary indicators = 1:function
> [...]
> subsection Boundary velocity model #velocity is prescribed on the right boundary to produce a balanced in- & outflow of material.
>    subsection Function
>       set Variable names      = x,z
>       set Function constants  = a=100.0*3600.0*24.0*365.25 , pi=3.14159
>       set Function expression = 5.0/a*cos(z/670000.*pi);0
>    end
> end
>
> The amplitude of the cosine is 5cm/year. If you look at the attached images, you'll see that the velocity flow pattern I get and its magnitude are plausible/satisfactory.
> However when I look at the statistics file I see that the RMS velocity (said to be in m/year) is around 6.5e5 and that the max velocity is around 1.6e6.
> Correspondingly the timetsep dt is around 7e-4 years which stalls my simulation. I also attach the statistics file.
> How is it this possible ?
>
> cheers,
>
> Cedric.
>
>
>
>
>
>
>
> _______________________________________________
> Aspect-devel mailing list
> Aspect-devel at geodynamics.org
> http://geodynamics.org/cgi-bin/mailman/listinfo/aspect-devel




--
Timo Heister
http://www.math.tamu.edu/~heister/