Bondgraphs for qualitative and quantitative systems modeling

BG (Bondgraphs) are a systems representation that uses systematically the analogies between the engineering disciplines and prepares efficiently for simulation, even without writing equations. At the same time, they are useful for qualitative simulation since they give an idea of system behavior by inspection. After an introduction to the BG method and symbols, application to thermodynamics, chemistry, and osmosis is discussed; this is mostly qualitative since parameters are not well known. A pressure regulating valve is used as a worked example of a quantitative engineering simulation, yet this system appears in the literature on qualitative reasoning.