Changes between Version 3 and Version 4 of u/erica/CylindricalGravity
- Timestamp:
- 08/18/14 13:52:14 (10 years ago)
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u/erica/CylindricalGravity
v3 v4 3 3 The governing equation is Poisson's equation for gravity, which for a given mass distribution can be solved for the gravitational potential. In astrobear, we use the potential to solve for the gravitational forces in the fluid. The equation we use for the resultant force is either in conservative or non-conservative form (want to read more into the numerical methods here and link to these pages). 4 4 5 === The Laplacian===5 === Laplace Operator === 6 6 7 7 8 8 In cartesian coordinates, the Laplacian contains only simple derivatives, i.e. does not contain any functions of position as it does in cylindrical or spherical coordinates. 9 9 10 Laplacian in Cartesian coordinates: 10 '''in Cartesian coordinates:''' 11 11 12 [[latex($\nabla^2 = \frac{\partial^2f}{\partial x^2} + \frac{\partial^2f}{\partial y^2} + \frac{\partial^2f}{\partial z^2} $)]] 12 13 14 '''in Cylindrical coordinates:''' 13 15 14 in Cylindrical coordinates: 16 [[latex($\nabla^2 = \frac{1}{\rho} \frac{\partial}{\partial \rho}(\rho \frac{\partial f}{\partial \rho}) + \frac{1}{\rho ^2}\frac{\partial^2 f}{\partial \phi^2} + \frac{\partial^2f}{\partial z^2} $)]] 15 17 16 in Spherical 18 '''in Spherical''' 17 19 18 and in 2.5 d: 20 '''and in 2.5 d:''' 19 21 20 22