A two-dimensional fluid model of snow plow type to simulate the plasma dynamics in a coaxial accelerator is described. The self-consistent model combines the description of the electric circuit with the plasma resistance and inductance, as well as the balance of magnetic and fluid pressures at the contact interface. The applicability of presented model has been proved by comparison of computational results with the high-speed photographs of plasma dynamics in the impulse plasma deposition (IPD) coaxial accelerator.