A large number of HPC applications migrate to Cloud Environments. These HPC applications include various Engineering and Physics type simulations. Gravitational N-body simulation is one of the most challenging and computationally intensive applications used to study evolutionary phenomena of galaxies or cosmological structures. The requirements of this type of simulation are introduced and discussed with respect to emerging service delivery models of Cloud environments, such as: WaaS and CloudLightning. Moreover, discussions about other types of Engineering and Physics simulations that can be performed in the Cloud along with advantages and disadvantages are given.