For a vector field \( \mathbf{D} = \rho \cos^2 \phi a_{\rho} + z^2 \sin^2 \phi a_{\phi} \) in a cylindrical coordinate system \( (\rho, \phi, z) \) with unit vectors \( a_{\rho}, a_{\phi}, a_z \), the net flux of \( \mathbf{D} \) leaving the closed surface of the cylinder \( (\rho = 3, 0 \leq z \leq 2) \) (rounded off to two decimal places) is .