Changes between Version 20 and Version 21 of u/GasPhiBE
- Timestamp:
- 10/04/12 16:09:28 (12 years ago)
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u/GasPhiBE
v20 v21 110 110 Now, this is where things get hard for me to understand. First, I see the range of phi, and magnitude of phi is drastically different for this matched ambient case. This may make sense, based on more mass in the ambient meaning stronger gravitational potential due to the ambient. However, I would expect that at very small radii, just above Rbe, the approximation of the ambient as a uniform sphere should be very good. This is because there is SOOOO much more mass in the ambient than in the sphere (see above calculation). Thus, very early on, I would expect the potential to be growing more and more negative as more and more mass is enclosed in this uniform sphere. Indeed, we see this behavior from the function derived above, but NOT in the simulation. Can someone please explain this discrepancy? 111 111 112 === =Update --- the importance of the integration constant ===112 === Update --- the importance of the integration constant === 113 113 114 114 Ah, so the potential needs to be calculated up to the correct additive constant, which the above formulation was NOT doing. I see now that by using Gauss's law to get the force, and integrating from infinity, the potential matches that of my sims. 115 115 116 116 [[Image(ForWiki1.png, 60%)]] 117 [[Image(NewPhiMatched.png, 60%)]] 118 [[Image(NewPhiLight.png, 60%)]] 117 [[Image(NewPhiMatched.png, 60%)]] Compare to:[[Image(LineMatchedPhi.png, 50%)]] 118 119 [[Image(NewPhiLight.png, 60%)]] Compare to:[[Image(LineLightPhi.png, 50%)]]
