Internal shocks in a relativistic wind as a source for gamma-ray bursts?

We investigate the recent proposal made by Rees and Mészáros (1994) that GRBs result from internal shocks in the relativistic wind emerging from two coalesced neutron stars. Using a simple model of that wind, where a large number of layers with different Lorentz factors interact through a series of mildly relativistic shocks we compute the efficiency of the process and the time profile of the resulting burst. We show that a great variety of profiles can be obtained using plausible initial distributions of Lorentz factors in the wind. However, the rather low overall efficiency (< 10%) of the process and limits imposed on the burst duration can be used to put severe constraints on the nature of the energy source.