Numerical simulations are import for analyzing Big Data and realizing applications in the Internet of Things. Running numerical simulations on mobile devices makes analyzing and reasoning about Big Data ubiquitous. However, mobile devices are limited in energy and compute resources, and connectivity to a dedicated infrastructure like a cloud cannot always be assured. Therefore, we propose to run the simulation on a distributed environment consisting of a mobile device and the cloud. This environment has a number of constraints for compute and network resources that need to be considered for providing simulation results in time and with high quality. In this paper we propose an architecture for mobile simulations and list challenges for realizing them.