Hi Vaclav,
I am trying to put energy trackers throughout the code. A point that
is not clear to me is how to compute energy dissipation due to the
numerical damping (especially with the aspherical integrator --). Can
elucidate that subject a bit?
I never thought about that before.
Thinking in 1D :
- numerical damping is like an added force in "acceleration=(f+f_d)/m"
- the work of this force on dt is (first order approximation)
dW=velocity*f_d, and this product is always negative by definition of
Cundall's damping.
dW is defined at the body level, not interactions. It is removed from
the system in Newton's integration.
This definition should apply for defining 6 dW_i corresponding to all 6
DOF's present in Newton integrator, since each DOF is damped independently.
Aspherical integration is apparently not damping rotational motion => no
dissipation.
If torque was damped like in spherical integration, there would probably
not be anything specific.
I hope it helps. Cheers.
Bruno
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