ADSLib Acoustic Duct Simulation ASPack Acoustic Simulation Library

ADSLib – Acoustic Duct Simulation ASPack – Acoustic Simulation Library Package EADS. Lib – European Acoustic Duct Simulation Library ARTSIM - Acoustic Real. Time Simulation Package A European Collaboration based on the Open Source Concept EMAS – European Musical Acoustics Simulation ARTSPAC – Acoustic Real-Time Simulation ADSS –Library Acoustic Duct Simulation Package Software

Goal of the project Simulation package for arbitrary topologies of acoustical ducts with realistic termination conditions.

Applications Computer Optimization of Wind Instruments n Interactive Design of Wind Instruments n Accurate Modeling of arbitrary topologies (e. g. ventilation duct systems, exhaust systems) n Bore reconstruction n Surface condition related loss reconstruction n Determination of true termination impedance n

Final Stage Single Mode, Multi Mode, 2 D+3 D CFD n Frequency Domain, Time Domain n Basic building blocks n straight and bent tubes and cones n various kinds of side holes, bells n various realistic (measured) termination conditions n loss coefficients related to certain surface conditions n n Easy interactive I/O, numerical & semigraphical

Primary Concepts Efficiency – never calculate something twice n Flexibility – allow any shape with shunt impedances (tone holes) n Extendibility – add new models at any time without invalidating application software n Generality – don’t restrict future models in any way, allow mixed mode simulation n Portability – generate code from abstract descriptions, don’t rely on specific compiler/OS n Team Development – strict interfaces n

Efficiency Hierarchical representation with pre-calculated propagation matrices of whole sections which are rarely modified. n Impedance cache for each section to avoid recalculation in case of constant upstream conditions. n Notification mechanism invalidates only those cache entries which are affected by the change of a geometric or acoustical property value. n

Example: Pressing a key Key up/down switches termination conditions A 3 A 1 ZUp A 2 ZIn ZBell ZOpen ZTerm= const ! Input Impedance known by CFD (e. g. Lattice-Boltzmann)

Example: Pressing a key Key up/down switches termination conditions A 3 A 1 ZDown A 2 ZIn ZBell ZOpen ZTerm= const ! Input Impedance known by CFD (e. g. Lattice-Boltzmann)

Extendibility, Generality Object oriented approach (inheritance of functionality, partial overload, new properties) n Generic application interface n Enumeration of model capabilities n Model communicates its properties by name, type and description n Application can register any property for subsequent modifications n n Generic model and wave datatypes

Portability ANSI C++ n No OS dependent libraries n Generic graphical output n Simple application interface compatible with VB, C++, Java, Delphi… n Open Source policy allows everybody to create its own applications from tested and proven technologies. n

Team Development UML Design n Abstract description of class dependencies enforces interface discipline n Documentation already on abstract level n Skeleton code generation for C++ includes all comments n Version control system n

UML Representation

Real-Time Simulation 0, 0 mm

Real-Time Simulation 0, 2 mm