We present gas flow models for the Milky Way based on high-resolution grid-based hydrodynamical simulations .
The basic galactic potential we use is from a N-body model constrained by the density of red clump giants in the Galactic bulge .
We augment this potential with a nuclear bulge , two pairs of spiral arms and additional mass at the bar end to represent the long bar component .
With this combined model we can reproduce many features in the observed ( l,v ) diagram with a bar pattern speed of 33 { km } { s } ^ { -1 } { kpc } ^ { -1 } and a spiral pattern speed of 23 { km } { s } ^ { -1 } { kpc } ^ { -1 } .
The shape and kinematics of the nuclear ring , Bania ’ s Clump 2 , the Connecting arm , the Near and Far 3-kpc arms , the Molecular Ring , and the spiral arm tangent points in our simulations are comparable to those in the observations .
Our results imply that a low pattern speed model for the bar in our Milky Way reproduces the observations for a suitable Galactic potential .
Our best model gives a better match to the ( l,v ) diagram than previous high pattern speed hydrodynamical simulations .