I would like to enter the field of heterogenous computing and would like to do simulations with different architectures. I know that one can make some VHDL code and run a test bench to see how that kind of simulation works, but I would like to know what other tools, researchers are using today? Maybe to simulate things like power, time delays etc. I also have seen instances where FPGA's are used for quickly emulating processor architectures, but I would like to know further.
Update/Edit: I am specifically looking for opensource or free tools (ex: Modelsim free version) .