  To study the star formation and feedback mechanism, we simulate the evolution
of an isolated dwarf irregular galaxy (dIrr) in a fixed dark matter halo,
similar in size to WLM, using a new stellar feedback scheme. We use the new
version of our original N-body/smoothed particle chemodynamics code, GCD+,
which adopts improved hydrodynamics, metal diffusion between the gas particles
and new modelling of star formation and stellar wind and supernovae (SNe)
feedback. Comparing the simulations with and without stellar feedback effects,
we demonstrate that the collisions of bubbles produced by strong feedback can
induce star formation in a more widely spread area. We also demonstrate that
the metallicity in star forming regions is kept low due to the mixing of the
metal-rich bubbles and the metal-poor inter-stellar medium. Our simulations
also suggest that the bubble-induced star formation leads to many
counter-rotating stars. The bubble-induced star formation could be a dominant
mechanism to maintain star formation in dIrrs, which is different from larger
spiral galaxies where the non-axisymmetric structures, such as spiral arms, are
a main driver of star formation.
