A suite of idealised , global , gravitationally unstable , star-forming galactic disc simulations with 2 pc spatial resolution , performed with the adaptive mesh refinement code ramses is used in this paper to predict the emergent effects of supernova feedback .
The simulations include a simplified prescriptions for formation of single stellar populations of mass \sim 100 M _ { \odot } , radiative cooling , photoelectric heating , an external gravitational potential for a dark matter halo and an old stellar disc , self-gravity , and a novel implementation of supernova feedback .
The results of these simulations show that gravitationally unstable discs can generate violent supersonic winds with mass loading factors \eta \gtrsim 10 , followed by a galactic fountain phase .
These violent winds are generated by highly clustered supernovae exploding in dense environments created by gravitational instability , and they are not produced in simulation without self-gravity .
The violent winds significantly perturb the vertical structure of the disc , which is later re-established during the galactic fountain phase .
Gas resettles into a quasi-steady , highly turbulent disc with volume-weighted velocity dispersion \sigma > 50 { km / s } .
The new configuration drives weaker galactic winds with mass loading factor \eta \leq 0.1 .
The whole cycle takes place in \leq 10 dynamical times .
Such high time variability needs to be taken into account when interpreting observations of galactic winds from starburst and post-starburst galaxies .