BAGPIPES-a program for analyzing acoustic transmission in ductwork

In BAGPIPES, system equations are generated automatically in the form of duct superelements. During generation, the superelements are formed by successively enclosing layers of elements, so that the complete superelement is described by only the number of nodes needed to describe a single layer. Consequently the interior nodes, which are not required for superelement conductivity, do not add to the size of the system. Limits on the model size arise from the number of superelement nodes required for connectivity. Once the superelements have been assembled, nodes which are not required for the application of boundary conditions and sound sources, or for the solution output are condensed from the system. The result of these reductions in savings in run time and the ability to model far larger systems than would otherwise be possible within the confines of a personal computer. The program has been used to model several fittings commonly found in HVAC systems. In addition, a network including a plenum chamber was modelled and results compared with a complementary experimental study of the acoustic transmission through the network