ASCEND modelling environment

ASCEND is a flexible modelling environment for solving hard engineering and science problems. It offers: an object-oriented model description language for describing your system, an interactive user interface that allows you to solve your model and explore the effect of changing the model parameters, and a scripting environment that allows you to automate your more complex simulation problems.
Find ASCEND modelling environment at: http://ascend.cheme.cmu.edu/