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I would be very glad if anyone could help me here - is there anything wrong with my code? but what could it be, as the code is not exactly rocket science - or at least tell me, if you think my thread was posted to the wrong section. I tried substituting the 0 with a small number like 10-4, but then the graph blows up ridiculously in the order of 1040. NDSolve::ndnum: Encountered non-numerical value for a derivative at r 0.
enter image description here I can't figure out why there be ' non-numerical value for a derivative at t 0 ', there shouldn't be the non-numerical value at t0, the whole Mt should be >0 when t<20. > Infinity::indet: 'Indeterminate expression 0.If you precede your code with alpha11 alpha22 alpha32 alpha42 alpha51, you. Also, NDSolve is strictly a numerical solver, so it doesnt understand or accept unknown symbolic values like alpha1, alpha2, et cetera. Name your constants alpha1 or 1 instead of alpha1. The orbits in xy plane should be circular and go "around" the torus (like a satellite).įor comparison, I also plotted the torus in the xy plane, as the orbits should be circular or at least elliptical, and they seem completely wrong - like if there was no torus at all, they cross the planet, which is of course wrong - something like the case shown in attachment, remember, this is the xy plane! NDSolve::ndnum: Encountered non-numerical value for a derivative at t 0. Do not use slashes and underlines in variable names, it does not work. X has been chosen close to the toroid (9.5), because the potential is lowest near the toroid. NDSolve solves the differential equation numerically in the specified domain. I need to solve a system of 2nd order differential equations, that look something like DSolve gives an analytical symbolic solution to the differential equation. Let’s choose the flow at Reynolds number 2,000. This again can be done very easily using NDSolve.
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I am computing orbits of constant energy in a gravitational potential of a complicated planet (sth like a torus). In Mathematica 9, some additional checks prevent NDSolve from integrating the equation MATLAB Codes for Finite Element. To visualize the actual motion of the flow, the box can be seeded with mass-less particles, and the particles are tracked in time as they are carried by the flow.