We present the first detailed hydrodynamic simulation of a superoutburst to
incorporate the full tidal potential of a binary system. A two-dimensional
smoothed particle hydrodynamics code is used to simulate a superoutburst i
n a binary with the parameters of the SU UMa system Z Chamaeleontis. The si
mulated light curves shows all the features observed in such systems. Analy
sis of the mass flux through the disc and the growth rate of the superhumps
and disc eccentricity show that the superoutburst-superhump phenomenon is
a direct result of tidal instability. No enhanced mass transfer from the se
condary is required to initiate or sustain these phenomena. Comparisons of
superoutbursts with normal outbursts are made and we show that the model ca
n be reconciled with the behaviour of U Geminorum-type dwarf novae, which s
how no superoutbursts.