Version 4 (modified by 9 years ago) ( diff ) | ,
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To implement angular momentum injection in our outflows, following Federrath 2014, we first define the following quantities:
these represent the total *accreted* mass (m_acc), center of mass (COM_acc), momentum (p_acc) and angular momentum (L_acc) from all the cells within the accretion volume surrounding the sink particle.
We use these quantities to (conservatively) update the particle's mass, COM, and so on, following:
where primes (') denote post-accretion quantities (i.e. m'-m represents the change in particle mass after an accretion event).
Now, angular momentum does not have the same form as above, namely:
as we might expect. This is because the position of the sink during the accretion event can change ever so slightly over the course of the accretion step, and thus, the angular momentum can change slightly as well (to maintain conservation of the com).. Thus, we instead write the angular momentum, post-accretion, as: