NGC 6782 is an early-type barred spiral galaxy exhibiting a rich and complex morphology with multiple ring patterns .
To provide a physical understanding of its structure and kinematical properties , two-dimensional hydrodynamical simulations have been carried out .
Numerical calculations reveal that the striking features in NGC 6782 can be reproduced provided that the gas flow is governed by the gravitational potential associated with a slowly rotating strong bar .
In particular , the response of the gaseous disk to the bar potential leads to the excitation of spiral density waves at the inner Lindblad resonance giving rise to the appearance of a nearly circular nuclear ring with a pair of dust lanes .
For a sufficiently strong bar potential , the inner 4:1 spiral density waves are also excited .
The interaction of the higher harmonic waves with the waves excited at the inner Lindblad resonance and confined by the outer Lindblad resonance results in the observed diamond-shaped ( or pointy oval ) inner ring structure .
The overall gas morphology and kinematical features are both well reproduced by the model provided that the pattern speed of the bar is \sim 25 km s ^ { -1 } kpc ^ { -1 } .