Changes between Version 37 and Version 38 of u/u/erica/BEboundary
- Timestamp:
- 05/30/13 13:23:59 (11 years ago)
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u/u/erica/BEboundary
v37 v38 24 24 Here are some lineouts I made at a 45-degree angle-- 25 25 26 [[Image( )]]26 [[Image(AmbRhoLineMat.gif, 35%)]] 27 27 28 28 = BP = … … 32 32 These plots show a very different scenario. The ambient remains quiescent in this case; the density of the ambient does not change and the radial velocity remains close to 0 out there. The only motions we see is inside of the BE sphere itself, as it undergoes classic outside-in collapse. The free fall time for the ambient in these cases is tff=40Myr, or t=2.38>>tsim. 33 33 34 [[Image(AmbRhoLineBP.gif, 35%)]] 35 34 36 = Ambient 1/3 = 35 37 … … 37 39 38 40 This case is closest to the Matched case. Here we see the effects of the Poisson boundary conditions in a similar way that we did above in the Matched case but not as exaggerated. That is, the velocity increases near the spherical boundary, but not as drastically. Near the end of the simulation, when the speeds have approached vrad/cs~4, we very quickly see a build up of density in the corresponding ambient region. I wonder if this time corresponds to the time we see a 'turn-over' in the solution from compression wave to classic collapse? The free-fall time of ambient in this case is tff = 7 Myr, or t=0.44>tsim=0.28. 41 42 [[Image(AmbRhoLinew3.gif, 35%)]] 39 43 40 44 = Ambient 1/10 = … … 44 48 Here the ambient remains quiescent most of the way through the simulation, as the BE sphere begins to collapse. We see only very late in the sim, after the collapse is well underway, a transonic flow begin to develop in the ambient medium, closer in to the sphere than the other cases. This is interesting, both the diminished strength of the flow speed and the closer proximity of the flow to the sphere, i.e. further away from the spherical boundary than in previous cases. This flow doesn't quite reach the BE sphere surface by the end of the simulation. The free-fall time of the ambient in this case is tff = 14 Myr, or in computational units, tff=0.7869 > tsim = 0.4. 45 49 50 [[Image(AmbRhoLinew10.gif, 35%)]] 51 46 52 = Ambient 1/30 = 47 53 … … 49 55 50 56 This case is nearest the stability case. The freefall time of the ambient is 24 Myr, and in computational time, t=1.4, which exceeds the time of the simulation, tsim=0.7 (see above table). The fact that we do not see any radial motions develop in the ambient medium over the course of the simulation is in agreement with the tff >> tsim. The only motions we see develop is inside of the sphere as it undergoes collapse. 57 58 [[Image(AmbRhoLinew30.gif, 35%)]] 51 59 52 60 = Stability Case = … … 56 64 The freefall time of the ambient is tff=43 Myr, or t=2.5>>tsim. 57 65 66 [[Image(AmbRhoLinew100.gif, 35%)]] 67 58 68 = Remarks = 59 69
