Changes between Version 1 and Version 2 of u/erica/UniformCollapse
- Timestamp:
- 06/29/15 12:41:25 (10 years ago)
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u/erica/UniformCollapse
v1 v2 1 Ignoring the pressure of the ambient, the local acceleration of a gas parcel at a distance r away from the origin for a uniform density sphere is given by: 1 '''Homologous Collapse of a uniform density sphere ''' 2 3 Ignoring the pressure forces in the gas (which is valid when the gas is Jeans unstable, i.e. [[latex($E_{grav}>>E_{kin}$)]]), the local acceleration of a gas parcel at a distance r away from the origin for a uniform density sphere is given by: 2 4 3 5 [[latex($\frac{d^2r}{dt^2} = -G\frac{M_r}{r^2}$)]] 4 6 5 7 6 Integrating this equation under the boundary conditions, the initial velocity [[latex($\frac{dr}{dt}=0$)]] and the initial radius is the radius of the sphere [[latex($r=r_0$)]], leads to an equation that describes the radius of the outer sphere over time, 8 Integrating this equation under the boundary condition, the initial velocity [[latex($\frac{dr}{dt}=0$)]] at the initial radius of the sphere [[latex($r=r_0$)]], leads to an equation that describes the radius of the outer sphere over time (i.e. over the course of collapse), and the velocity at this radius over time. 9