Viscous fluid dynamical calculation of the reactionC12(85 MeV/nucleon) +Au197

Proton spectra have been calculated for the reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(85 MeV/nucleon) + ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$ using a three-dimensional hydrodynamical model with viscosity and thermal conductivity and final thermal breakup. The theoretical results are compared to recent data. It is shown that the predicted flow effects are not observable as a result of the impact parameter averaging inherent in the inclusive proton spectra. In contrast, angular distributions of medium mass nuclei ($A>\mathrm{}3\mathrm{}$) in nearly central collisions can provide signatures for flow effects.