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Progress on Forward Modeling for Acoustic-Propagation Simulations. Joe Werne (1) Keith Julien (2) (1) NorthWest Research Associates, Inc. (NWRA) Colorado Research Associates Division (CoRA) 3380 Mitchell Lane, Boulder, CO 80301 werne@cora.nwra.com
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Progress on Forward Modeling for Acoustic-Propagation Simulations Joe Werne(1) Keith Julien(2) (1)NorthWest Research Associates, Inc. (NWRA) Colorado Research Associates Division (CoRA) 3380 Mitchell Lane, Boulder, CO 80301 werne@cora.nwra.com (2)Department of Applied Mathematics University of Colorado, Boulder, CO julien@colorado.edu Julien, Werne CU, CoRA/NWRA
Progress on Forward Modeling for Acoustic-Propagation Simulations • Code Development: • Cartesian Geometry • Linear Acoustic Modes • 3D MHD • Spectral Accuracy in all 3 Directions • 3rd-order Runge-Kutta time stepping w/internal Newton-Raphson iteration scheme for implicit operations • Currently generalizing and adapting wave-radiation formalism for acoustic-wave radiation Julien, Werne CU, CoRA/NWRA
Progress on Forward Modeling for Acoustic-Propagation Simulations • Test Cases: • Acoustic wave-packet propagation, inviscid evolution • 1-D with constant sound speed (test diffusion/dispersion) • 3-D density anomaly (coin in two orientations) Julien, Werne CU, CoRA/NWRA
Progress on Forward Modeling for Acoustic-Propagation Simulations 1)1-D with constant sound speed (test numerical diffusion/dispersion): 0 dt 140 dt 280 dt After 2400 dt, amplitude drops by 0.7%. Negligible dispersion and diffusion errors. gridpoint gridpoint Julien, Werne CU, CoRA/NWRA
50 Mm 12.5 Mm C1=50 km/s Progress on Forward Modeling for Acoustic-Propagation Simulations 2)3-D density anomaly (coin in two orientations): C0=36 km/s Julien, Werne CU, CoRA/NWRA
Progress on Forward Modeling for Acoustic-Propagation Simulations 2)3-D density anomaly (coin in two orientations): Julien, Werne CU, CoRA/NWRA
l = 4Mm n = 5 mHz 22 Mm Progress on Forward Modeling for Acoustic-Propagation Simulations 2)3-D density anomaly (coin in two orientations): Julien, Werne CU, CoRA/NWRA
Progress on Forward Modeling for Acoustic-Propagation Simulations 2)3-D density anomaly (coin in two orientations): Julien, Werne CU, CoRA/NWRA
Progress on Forward Modeling for Acoustic-Propagation Simulations 2)3-D density anomaly (coin in two orientations): February 2004 Julien, Werne CU, CoRA/NWRA Julien, Werne CU, CoRA/NWRA
Progress on Forward Modeling for Acoustic-Propagation Simulations • Continued Test Work: • Sound-speed perturbations • Subsurface flows • Subsurface magnetic fields Julien, Werne CU, CoRA/NWRA