The use of flow-based design tools in engineering is a reasonably new trend. Unified Modeling Language is the most widely-used example for software design. The use of flow-based design tools allows for more holistic system design and faster development. C to HDL tools and flow have a similar aim, but with C or C-like programming languages.
Most applications are ones which take too long with existing supercomputer architectures. These include bioinfomatics, CFD, financial processing and oil and gas survey data analysis. Embedded applications that require high performance or real-time data processing are also an area of use. System-on-a-chip design can also be done using this flow.
Xilinx System Generator from
StarBridge VIVA from defunct <s></s>
an overview of flows by Daresbury Labs.
Xilinx's ESL initiative, some products listed and C to VHDL tools.