
Accession Number : ADA297994
Title : Modeling Flue Pipes: Subsonic Flow, Lattice Boltzmann, and Parallel Distributed Computers.
Descriptive Note : Technical rept.,
Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE ARTIFICIAL INTELLIGENCE LAB
Personal Author(s) : Skordos, Panayotis A.
PDF Url : ADA297994
Report Date : JAN 1995
Pagination or Media Count : 260
Abstract : The problem of simulating the hydrodynamics and the acoustic waves inside wind musical instruments such as the recorder the organ, and the flute is considered. The problem is attacked by developing suitable localinteraction algorithms and a parallel simulation system on a cluster of nondedicated workstations. Physical measurements of the acoustic signal of various flue pipes show good agreement with the simulations. Previous attempts at this problem have been frustrated because the modeling of acoustic waves requires small integration time steps which make the simulation very computeintensive. In addition, the simulation of subsonic viscous compressible flow at high Reynolds numbers is susceptible to slowgrowing numerical instabilities which are triggered by highfrequency acoustic modes. The numerical instabilities are mitigated by employing suitable explicit algorithms: lattice Boltzmann method, compressible finite differences, and fourthorder artificialviscosity filter. Further, a technique for accurate initial and boundary conditions for the lattice Boltzmann method is developed, and the secondorder accuracy of the lattice Boltzmann method is demonstrated. The computeintensive requirements are handled by developing a parallel simulation system on a cluster of nondedicated workstations. The system achieves 80 percent parallel efficiency (speedup/processors) using 20 HPApollo workstations. The system is built on UNIX and TCP/IP communication routines, and includes automatic process migration from busy hosts to free hosts. (AN)
Descriptors : *COMPUTERIZED SIMULATION, *ACOUSTIC WAVES, *COMPUTATIONAL FLUID DYNAMICS, *SUBSONIC FLOW, MATHEMATICAL MODELS, ALGORITHMS, DISTRIBUTED DATA PROCESSING, COMPUTER PROGRAMMING, PARALLEL PROCESSING, FINITE DIFFERENCE THEORY, COMPRESSIBLE FLOW, FLOW FIELDS, NUMERICAL INTEGRATION, ACOUSTIC SIGNALS, MACH NUMBER, NAVIER STOKES EQUATIONS, VISCOUS FLOW, VISCOSITY, HYDRODYNAMICS, REYNOLDS NUMBER, INCOMPRESSIBLE FLOW, BOLTZMANN EQUATION, SHEAR FLOW.
Subject Categories : Acoustics
Fluid Mechanics
Computer Programming and Software
Distribution Statement : APPROVED FOR PUBLIC RELEASE