*HEADING
EC38AFAW: Nonreflective end-condition with large drag with AC3D8
Compare IMPEDANCE WITH SIMPEDANCE, and STEADY STATE DYNAMICS, DIRECT
with SUBSPACE PROJECTION.
********************
*RESTART,WRITE
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**
**   Mesh Generation
**
*NODE, Nset=ODB_NSET
*NGEN,NSET=NALL
*NSET,NSET=LOAD
*NSET,NSET=QA_TEST,GENERATE
*ELEMENT,TYPE=AC3D8,ELSET=EALL
*ELGEN,ELSET=EALL
*ELSET,ELSET=NONREF
*surface,NAME=NRS
NONREF,S4
*SOLID SECTION,MATERIAL=ABSORB,ELSET=EALL
**
*MATERIAL,NAME=ABSORB
*DENSITY
 1.21,
*ACOUSTIC MEDIUM,BULK MODULUS
*ACOUSTIC MEDIUM,VOLUMETRIC DRAG
*AMPLITUDE,NAME=OMEGA
0.,0., 1E6,6.2831853E6
************************************************
**       ** ANALYTIC SOLUTION  **
**
**  at freq=100,
**  Impedance: Z = root( K_f (rho  - i r/omega))
**               = 516.411 -307.208 i
**  Propagation constant
**             b = i (omega/K_f) Z
**               = 1.35551 + 2.27859 i
**
**  Solution: with nonreflective end,
**  Complex pressure
**             p(x) = Z v(0) exp( - b x)
**  i.e. |p(x)| = |Z v(0)| exp ( - Re(b) x)
**              = 600.8805  exp ( -1.35551 x)
**
**       Arg(p) = Arg(Z) - Im(b) x
**       ppor   = -30.74799 - 130.5534 x
**
************************************************
*STEP
*STEADY STATE DYNAMIC,DIRECT
*IMPEDANCE
 NONREF,I4
**
** Conditions at x=0 : Define the source inward accel
**  to be  a =  omega i, so v (inward) = 1.
**
**  Area of face=A. Total inward VOLUME acceleration
**  is A*a. 1/4 of this should be distributed to each
**  of the corner nodes:
*CLOAD,LOAD CASE=2, AMP=OMEGA
LOAD, 8, 1.e0
*ENERGYPRINT
*NODE PRINT, NSET=QA_TEST
COORD,POR,PPOR
*OUTPUT,FIELD
*NODE OUTPUT
POR,
*ELEMENTOUTPUT
ENER,ELEN,ELEDEN
*OUTPUT,HISTORY
*NODE OUTPUT,NSET=QA_TEST
POR,
*ENERGYOUTPUT
ALLQB,ALLWK,ALLVD,ALLSE,ALLKE
*END STEP
**
**
*STEP
*STEADY STATE DYNAMIC,DIRECT
*SIMPEDANCE
 NRS,
*CLOAD,LOAD CASE=2, AMP=OMEGA
LOAD, 8, 1.
*ENERGYPRINT
*NODE PRINT, NSET=QA_TEST
COORD,POR,PPOR
*OUTPUT,FIELD
*NODE OUTPUT,NSET=QA_TEST
POR,
*ELEMENTOUTPUT
ENER,ELEN,ELEDEN
*OUTPUT,HISTORY
*NODE OUTPUT,NSET=QA_TEST
POR,
*ENERGYOUTPUT
ALLQB,ALLWK,ALLVD,ALLSE,ALLKE
*END STEP
**
**
*STEP
*FREQUENCY,NORM=MASS,EIGENSOLVER=LANCZOS
50, , ,
*NODE PRINT,F=0
*EL PRINT,F=0
*OUTPUT,FIELD,Frequency=0
*END STEP
**
**
*STEP
*STEADY STATE DYNAMIC,SUBSPACE PROJECTION
*IMPEDANCE
 NONREF,I4
*CLOAD,LOAD CASE=2, AMP=OMEGA
LOAD, 8, 1.
*ENERGYPRINT
*OUTPUT,FIELD
*NODE OUTPUT
POR,
*ELEMENTOUTPUT
ENER,ELEN,ELEDEN
*OUTPUT,HISTORY
*ENERGYOUTPUT
ALLQB,ALLWK,ALLVD,ALLSE,ALLKE
*END STEP
**
*STEP
*STEADY STATE DYNAMIC,SUBSPACE PROJECTION
*SIMPEDANCE
 NRS,
*CLOAD,LOAD CASE=2, AMP=OMEGA
LOAD, 8, 1.
*ENERGYPRINT
*OUTPUT,FIELD
*NODE OUTPUT
POR,
*ELEMENTOUTPUT
ENER,ELEN,ELEDEN
*OUTPUT,HISTORY
*NODE OUTPUT,NSET=QA_TEST
POR,
*ENERGYOUTPUT
ALLQB,ALLWK,ALLVD,ALLSE,ALLKE
*END STEP