SV.v_zero ========= A multiple of the local sound speed or a fixed speed at the base of the wind. This results in the initial velocity of the wind being able to be greater or less than the local sound speed. Type Double Unit ['Speed of sound in the wind' or 'cm/s'] Values Greater than 0 File `sv.c `_ Parent(s) * :ref:`SV.v_zero_mode`: ``sound_speed``, ``fixed``