[yt-users] Mass Flux Across Surface Binned By Velocity

[Nathan Goldbaum]

And you can get the positions of the cell centers with surface['x'],
surface['y'], and surface['z'].


On Mon, Jul 7, 2014 at 2:42 PM, Michael Zingale <
michael.zingale at stonybrook.edu> wrote:

> If you are ok with using the normal of the cell-center of the zone instead
> of reconstructing how the surface cuts through a zone and computing the
> normal to that surface (which seems a bit like a level-set technique),
> then, taking the origin at 0,0,0, the normal velocity is just the radial
> velocity:
>
> v_r = v_x (x/r) e_x + v_y (y/r) e_y + v_z (z/r) e_z
>
> where e_i is the unit vector in the respective Cartesian direction x,y,z
> are the Cartesian coordinates (with respect to the center) and r is the
> radial distance.
>
>
>
>
> On Mon, Jul 7, 2014 at 3:16 PM, Melinda Soares-Furtado <
> msoares.physics at gmail.com> wrote:
>
>> This is great. Now I just need to figure out how to get the total
>> velocity normal to the surface.
>>
>> Regards,
>> Melinda Soares-Furtado
>> msoares at princeton.edu
>> http://cargo.ucsc.edu/msoares
>> 415-860-0438
>>
>>
>>
>> On Thu, Jul 3, 2014 at 7:00 PM, Nathan Goldbaum <nathan12343 at gmail.com>
>> wrote:
>>
>>> Hi Melinda,
>>>
>>> I believe you'll be able to construct that by extracting the x,y,z
>>> velocity fields and Density fields from the surface object:
>>>
>>> vx, vy, vz = surf['x-velocity'], surf['y-velocity'], surf['z-velocity']
>>> dens = surf['Density']
>>>
>>> These will be four flat numpy arrays which correspond to the values of
>>> the velocity and density fields at the surface boundary.
>>>
>>> Hope that helps,
>>>
>>> Nathan
>>>
>>>
>>> On Thu, Jul 3, 2014 at 2:19 PM, Melinda Soares-Furtado <
>>> msoares.physics at gmail.com> wrote:
>>>
>>>> Hello, folks. I have a code that is computing the flux across a sphere
>>>> of a given radius, as shown below. This code provides me with the
>>>> summed flux across the surface, however what I am hoping to do is to bin
>>>> this flux up into various velocities ranging from v_min to v_max. Thus,
>>>> determine the mass flux across the surface for a chosen velocity bin.
>>>>
>>>> Does anyone know of a simple way to read out flux for a given velocity
>>>> (normal to the surface) rather than the summed total?
>>>>
>>>> Code:
>>>>
>>>>
>>>>
>>>> from yt.mods import *
>>>> pf=load("/trove/msoares/50Stars_LRefine5_Derefine0.05_velocity/50Stars_hdf5_plt_cnt_0200")
>>>> rad=0.1/pf['pc']
>>>> sp = pf.h.sphere([0,0,0],2.0*rad)
>>>> surf = pf.h.surface(sp,"Radius",rad)
>>>> flux = surf.calculate_flux("x-velocity","y-velocity","z-velocity","Density")
>>>> print flux
>>>>
>>>>
>>>> Regards,
>>>> Melinda Soares-Furtado
>>>>
>>>> _______________________________________________
>>>> yt-users mailing list
>>>> yt-users at lists.spacepope.org
>>>> http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org
>>>>
>>>>
>>>
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>>
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>>
>
>
> --
> Michael Zingale
> Associate Professor
>
> Dept. of Physics & Astronomy • Stony Brook University • Stony Brook, NY
> 11794-3800
> *phone*:  631-632-8225
> *e-mail*: Michael.Zingale at stonybrook.edu
> *web*: http://www.astro.sunysb.edu/mzingale
>
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