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Julien, Werne CU, CoRA/NWRA
February 2004
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 [email protected]
(2)Department of Applied Mathematics University of Colorado, Boulder, CO [email protected]
Julien, Werne CU, CoRA/NWRA
February 2004
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
February 2004
Progress on Forward Modeling for Acoustic-Propagation Simulations
Test Cases:
Acoustic wave-packet propagation, inviscid evolution
1) 1-D with constant sound speed (test diffusion/dispersion)
2) 3-D density anomaly (coin in two orientations)
Julien, Werne CU, CoRA/NWRA
February 2004
Progress on Forward Modeling for Acoustic-Propagation Simulations
1) 1-D with constant sound speed (test numerical diffusion/dispersion):
gridpoint
gridpoint
0 t 140 t 280 t After 2400 t, amplitude drops by 0.7%.
Negligible dispersion and diffusion errors.
Julien, Werne CU, CoRA/NWRA
February 2004
Progress on Forward Modeling for Acoustic-Propagation Simulations
2) 3-D density anomaly (coin in two orientations):
12.5 Mm
50 Mm C0=36 km/s
C1=50 km/s
Julien, Werne CU, CoRA/NWRA
February 2004
Progress on Forward Modeling for Acoustic-Propagation Simulations
2) 3-D density anomaly (coin in two orientations):
Julien, Werne CU, CoRA/NWRA
February 2004
Progress on Forward Modeling for Acoustic-Propagation Simulations
2) 3-D density anomaly (coin in two orientations):
22 Mm
4Mm 5 mHz
Julien, Werne CU, CoRA/NWRA
February 2004
Progress on Forward Modeling for Acoustic-Propagation Simulations
2) 3-D density anomaly (coin in two orientations):
Julien, Werne CU, CoRA/NWRA
February 2004
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
February 2004
Progress on Forward Modeling for Acoustic-Propagation Simulations
Continued Test Work:
Sound-speed perturbations
Subsurface flows
Subsurface magnetic fields
