  The origin of grand design spiral structure in galaxies is still under debate
but one of promising scenarios involves tidal interactions. We use N-body
simulations to study the evolution of a Milky Way-size galaxy in a Virgo-like
cluster. The galaxy is placed on a typical eccentric orbit and evolved for 10
Gyr. We find that grand design spiral arms are triggered by pericenter passages
and later on they wind up and dissipate. The arms formed in the simulations are
approximately logarithmic, but are also dynamic, transient and recurrent.
