01665nam 2200469I 450 991070587740332120170725143550.0(CKB)5470000002453640(OCoLC)994295750(EXLCZ)99547000000245364020170724j199803 ua 0engurbn|||||||||txtrdacontentcrdamediacrrdacarrierPreconditioning the Helmholtz equation for rigid ducts /Kenneth J. Baumeister, Kevin L. KreiderCleveland, Ohio :National Aeronautics and Space Administration, Lewis Research Center,March 1998.1 online resource (18 pages) illustrationsNASA technical memorandum ;107349"March 1998.""Performing organization: National Aeronautics and Space Administration, Lewis Research Center"--Report documentation page.Includes bibliographical references (pages 5-6).Acoustic propagationnasatDuctsnasatHelmholtz equationsnasatFinite difference theorynasatPreconditioningnasatAcoustic propagation.Ducts.Helmholtz equations.Finite difference theory.Preconditioning.Baumeister Kenneth J.1400246Kreider Kevin L.Lewis Research Center,GPOGPOBOOK9910705877403321Preconditioning the Helmholtz equation for rigid ducts3485381UNINA