Changes between Version 50 and Version 51 of u/erica/CoreCollapseBlog
- Timestamp:
- 04/17/18 15:31:07 (7 years ago)
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u/erica/CoreCollapseBlog
v50 v51 1 = = 4/15/18 ==1 = 4/15/18 = 2 2 3 3 Fixed the AMR criteria so that just the inner regions of the sphere are refined and moved to modeling the collapse in 3D, simulating an octant of the domain (running the full cube or an octant didn't make a noticeable difference in the behavior of the boundaries). 4 4 5 Running the code for 2 freefall times using the initial peak density of the sphere (~50 milliseconds) :5 Running the code for 2 freefall times using the initial peak density of the sphere (~50 milliseconds), where the freefall time is given by: 6 6 7 7 $t_{ff}\approx .5 \frac{1}{\sqrt{G \rho}}$ 8 9 === Domain and IC's === 8 10 9 11 || $T_{sim}$ || $.6 (CU) \approx 2 ~tff$ || 10 12 || Hydro BC's ||Outflow only (stepping on outer density and temp) on outward facing sides, reflecting on inside faces|| 11 13 || Poisson BC's || Multipole on outward facing sides, reflecting on inner || 12 || Self-gravity || On ||13 14 || Lx = Ly = Lz (CU) || [0, 2] || 14 15 || Clump radius (CU) || R_clump = 1 (CU) || … … 18 19 || Eff. resolution (CU) || dx = .001953125 (CU) || 19 20 || Eff. resolution (cm) || dx = 1.43e+7 (cm) || 21 || Mtot (total mass in box) || Mbox = 5 solar masses || 22 || Msphere || Msphere = 3 solar masses || 20 23 21 Things to still work-on: 24 === Physics === 25 26 || EOS || Ideal gas || 27 || $\gamma$ || 5/3 || 28 || Cooling || Not turned on -- need to add neutrino source term cooling || 29 || Self-gravity || On || 30 31 === Things to still work-on === 22 32 23 33 -Sink particle initialization to match progenitor mass?[[br]] … … 27 37 -Add magnetic fields 28 38 29 === = Post-interpolation onto Mesh: Checking HSE ====39 === Results === 30 40 31 As shown below, the profiles generated by AstroBEAR's HSE module closely match the input progenitor profiles, which are in HSE. Interpolation onto the grid for the hydro simulation can be closer or further from these initial profiles depending on resolution as the following line plot shows: 41 ==== Checking HSE after interpolation of profile onto mesh: ==== 42 43 As shown below (post from 3/15), the profiles generated by AstroBEAR's HSE module closely match the input progenitor profiles, which are in HSE. How well the simulation data matches the input progenitor profile following Interpolation onto the mesh then depends on the resolution. The following line plot shows that increasing the resolution by a factor of 8 (blue curve) improves the accuracy of the HSE solver -- the sphere reaches HSE over much smaller region in the higher resolution case rather than the lower resolution run. It seems HSE is achieved by about 30 grid cells on the finest mesh -- thus, want to minimize the physical distance these cells take up within the sphere. 32 44 33 45 [[Image()]] 34 46 35 At a resolution of ~, the sphere is very close to HSE within .1 of its radius.47 At an effective resolution of ~$dx = .0019$, the sphere is very close to HSE within .1 of its radius. 36 48 37 = = 3/15/ 18 ==49 = 3/15/ 18 = 38 50 39 51 Running the same setup but at 8x higher resolution gives profiles that more closely match the input progenitor density: … … 59 71 I also might need to adjust $\gamma$ in these simulations to more closely match the progenitor peak temperature of T=7e+9. $\gamma = 1.667$ in this simulation setup. 60 72 61 = = 3/15/18 ==73 = 3/15/18 = 62 74 63 75 Have a working 2D solution on the grid — … … 92 104 The run files used to produce this simulation are attached as "*.*_mar15" 93 105 94 = = 3/5/18 ==106 = 3/5/18 = 95 107 96 108 The HSE module takes as input: … … 103 115 [[Image(Screen Shot 2018-03-01 at 9.50.04 AM.png,50%)]] 104 116 105 = = 2/28/18 ==117 = 2/28/18 = 106 118 107 119 To get the progenitor profiles from excel into a fortran readable format for astrobear, open the desired sheet and go to save as. Select “MS-DOS formatted text (.txt)”. … … 109 121 The input file for the code needs to have the number of entries as a header, the next line specifies column values and units, and the following nentries lines have the values of the progenitor separated by spaces. (See example attached to this page). 110 122 111 = = 2/26/18 ==123 = 2/26/18 = 112 124 113 125 The Lane Emden equation non-dimensionalizes the HSE equation in an attempt to find analytic solutions. However, analytic solutions only exist for certain values of the polytropic index. Thus, if we are looking for numerical solutions, we can instead just start with the equation of HSE in spherical coordinates and discretize it: … … 124 136 125 137 126 = = 2/7/18 ==138 = 2/7/18 = 127 139 128 140 Fryer sent progenitor data. The density, pressure, temperature, and velocity profiles of this progenitor look like: … … 153 165 154 166 155 = = 2/5/18 ==167 = 2/5/18 = 156 168 157 169 We would like to model the progenitor of a core collapse supernova in astrobear. The project will be a parameter study to explore the role of magnetic fields and turbulent perturbations on the collapsing core.
