An alternative is to use np.ravel:
>>> np.zeros((3,3)).ravel()
array([ 0., 0., 0., 0., 0., 0., 0., 0., 0.])
The importance of ravel over flatten is ravel only copies data if necessary and usually returns a view, while flatten will always return a copy of the data.
To use reshape to flatten the array:
tt = t.reshape(-1)