bad_bursters
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bad_bursters [2014/06/03 17:50] lauer |
bad_bursters [2014/06/09 13:24] (current) lauer |
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| ====== Bad Bursters Logbook ====== | ====== Bad Bursters Logbook ====== | ||
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| ===== Log Book ===== | ===== Log Book ===== | ||
| - | * Input Person (Sarah Schwartz) | + | ===Input: Sarah Schwartz=== |
| - | * [ ] Looking up accretion rates for | + | * [X] X-ray bursts |
| - | * [ ] X-ray bursts | + | * [X] Accretion rate ~ 10^-8 Solar Mass / yr |
| - | * [ ] Novae | + | * [X] Radius ~ 10-15 km |
| + | * [X] Mass ~ 1 Solar Mass | ||
| + | * [X] Novae | ||
| + | * [X] Accretion rate ~ 10^-9 Solar Mass / yr | ||
| + | * [X] Radius ~ 10^4 km | ||
| + | * [X] Mass ~ 1 Solar Mass | ||
| * [ ] Density of in falling material | * [ ] Density of in falling material | ||
| - | * [ ] Masses of objects | + | * [X] Alpha parameter = 0<alpha<1 |
| - | * [ ] Alpha parameter | + | ===Code: Justin Brown=== |
| - | * Code Person (Justin Brown) | + | [[https://github.com/brownjustinmichael/VH1|Link to Code on GitHub]] |
| * 2D | * 2D | ||
| * [X] Get the VH-1 polar model working. | * [X] Get the VH-1 polar model working. | ||
| + | * Set ngeomx = 1 (radial cylindrical), ngeomy = 3 (theta), nlefty = 3, nrighty = 3 (periodic) | ||
| * [X] Set up accretion | * [X] Set up accretion | ||
| + | * Set nrightx = 2 (constant inflow), uotflo * rotflo * outer area of simulation (2 * pi * xmas) = 1 | ||
| + | * Set votflo to be the desired velocity at the boundary edge | ||
| * [X] Implement gravity | * [X] Implement gravity | ||
| - | * [ ] Implement an alpha viscosity model. | + | * In forces, set grav (n) under sweep "x", cylindrical to be -GM/xao(n)**2 |
| - | * Analysis Person (Amber Lauer) | + | * [X] Implement a viscosity model. |
| + | * We're choosing to use the derivative in the radial direction of only the tangential coordinate | ||
| + | * alpha*1/r(dv/dr)+alpha*d2v/dr2 | ||
| + | * In forces, set grav (n) under sweep "y", cylindrical angle to the above expression | ||
| + | * [X] Run Models | ||
| + | * [X] Non-dimensionalize | ||
| + | * The length unit is the radius of the neutron star, R_ns | ||
| + | * The time unit is sqrt (R_ns^3/GM_ns) | ||
| + | * The mass unit is M'sqrt (R_ns^3/GM_ns), where M' is the mass infall rate | ||
| + | * [X] Determine free parameters | ||
| + | * Outer radius of simulation, xmax | ||
| + | * Infall velocity, uotflo | ||
| + | * Viscosity, alpha | ||
| + | * Tangential initial velocity, votflo | ||
| + | * [X] Run models with uotflo = -0.1, votflo = 0.2, xmax = 10.0 | ||
| + | * [X] Viscid (alpha = 1.0) | ||
| + | * [X] Semi-Viscid (alpha = 0.1) | ||
| + | * [X] Inviscid (alpha = 0.0) | ||
| + | * [] Run models with uotflo = -1.0, votflo = 0.2, xmax = 10.0 | ||
| + | ===Analysis: Amber Lauer=== | ||
| * [x] Get visualization working | * [x] Get visualization working | ||
| * [x] Install NetCDF | * [x] Install NetCDF | ||
| - | −visit on ubuntu/linux was a quagmire, went with windows virtualbox installation :( | + | * visit on ubuntu/linux was a quagmire, went with windows virtualbox installation :( |
| * [x] Gathering the initial conditions for novae and X-ray bursts | * [x] Gathering the initial conditions for novae and X-ray bursts | ||
| - | −have average values for NS and WD, time permitting will constrain to single case and derive from scratch | + | * have average values for NS and WD, time permitting will constrain to single case and derive |
| - | * [ ] Determine the input abundances | + | *[x] PRESENTATION |
| - | * [ ] Build the nuclear network for the problem | + | * [x] Outline concepts and highlight theory for presentation |
| - | * [ ] Take output from the codes and determine when hydrogen burning begins | + | * [x] Encode .cdf data to video for presentation |
| + | * [x] Compile references for presentation | ||
| + | * [x] Compile images for presentation | ||
| + | |||
| + | |||
| + | Determined to be outside scope of project. | ||
| + | <del> | ||
| + | * [ ] Determine the input abundances | ||
| + | * [ ] Build the nuclear network for the problem | ||
| + | * [ ] Take output from the codes | ||
| + | * [ ]determine when hydrogen burning begins | ||
| + | * [ ]analyze data values to optimize scale(linear vs log) and ranges(0-?) for visualization | ||
| + | </del> | ||
| + | |||
| + | =====RESULTS===== | ||
| + | 1D on a solid surface was successful so the 2D case was the bulk of the project work. The solid case was unstable and resulted in an non-physical explosion. Both the infall and reflective cases were attempted, we found the [] to be optimal. We were able to model a non-viscous and viscous case using hydronamic force and energy equation. Terms for the extremely large B field (10^7-8 T) were not included. Both accreted around the central mass with a large high pressure/empty barrier for the non-viscous case, as the angular momentum is not dissipated. The viscous case correctly accreted on to the surface. | ||
| + | |||
| + | [[https://docmgmt.nscl.msu.edu/share/proxy/alfresco/api/node/content/workspace/SpacesStore/8e4a7857-347b-4603-9f64-bf2422ff5e7e/Simulating%20Accretion%20on%20Degenerate%20Matter%20to%20Model%20Surface.pdf|Presentation PDF]] | ||
| + | |||
| + | [[https://docmgmt.nscl.msu.edu/share/proxy/alfresco/api/node/content/workspace/SpacesStore/e6353d93-8726-45d6-bcf4-d2e3366fdb46/inviscid.mpg|video of non viscous accretion]] | ||
| + | |||
| + | [[https://docmgmt.nscl.msu.edu/share/proxy/alfresco/api/node/content/workspace/SpacesStore/507d83f6-8cc2-46c4-a1ee-34fc6e3e3889/viscous.mpg|video of viscous accretion]] | ||
| + | |||
| + | [[https://docmgmt.nscl.msu.edu/share/proxy/alfresco/api/node/content/workspace/SpacesStore/d4a5588e-c2ce-4136-bb49-78cbf8b1e959/zero%20pressure.mpg|video of accidental zero pressure accretion]] | ||
| + | |||
| + | |||
| + | References: | ||
| + | *Accretion Power in Astrophysics - Frank, King, Raine | ||
| + | *Accretion Disk for Beginners : [[http://www.astronomy.ohio-state.edu/~ryden/ast825/ | External Link]] (Notes PDF) | ||
| + | (further resources in presentation) | ||
| - | Link to Code on GitHub: [[https://github.com/brownjustinmichael/VH1|External Link]] | ||
| ~~DISCUSSION|Comments~~ | ~~DISCUSSION|Comments~~ | ||
bad_bursters.1401832246.txt.gz · Last modified: 2014/06/03 17:50 by lauer
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