A.forced vertex at the centre and free vortex outside
B.forced cortex at the centre as well as outside
C.free vortex at the centre and forced vortex outside
D.free vortex at the centre as well as outside
A.forced vertex at the centre and free vortex outside
B.forced cortex at the centre as well as outside
C.free vortex at the centre and forced vortex outside
D.free vortex at the centre as well as outside