Glass half full: sound synthesis for fluid–structure coupling using added mass operator

We present a fast and practical method for simulating the sound of non-empty objects containing fluids. The method is designed and demonstrated for use in interactive 3D systems, where live sound synthesis is important. The key contribution of this work is to enhance the sound synthesis equation in the rigid-body audio pipeline to account for the fluid force on an object at the fluid–structure boundary. Additions include pre-processing steps to identify the mesh nodes of a tetrahedralized object that are in contact with the liquid and to apply an added mass operator to those structural boundary nodes and adjacent solid domain nodes by increasing their corresponding elements in the mass matrix proportional to the liquid’s density, which may vary with temperature and/or type of fluids. Our technique generalizes to any impermeable tetrahedral mesh representing the rigid objects and inviscid liquids.