*HEADING
EC3KAFAW: Nonreflective end-condition with large drag with AC3D20
Compare IMPEDANCE WITH SIMPEDANCE, and STEADY STATE DYNAMICS, DIRECT
with SUBSPACE PROJECTION.
********************
*RESTART,WRITE
********************
**
**   Mesh Generation
**
*NODE, Nset=ODB_NSET
1,    0, 0
41,  .5, 0
51,   0, 1.
91,  .5, 1.
101,  0, 2.
141, .5, 2.
501,  0,  0, 1.
541, .5,  0, 1.
601,  0, 2., 1.
641, .5, 2., 1.
1001, 0,  0, 2.
1041,.5,  0, 2.
1051, 0, 1., 2.
1091,.5, 1., 2.
1101, 0, 2., 2.
1141,.5, 2., 2.
*NGEN,NSET=NALL
1,41
51,91
101,141
501,541
601,641
1001,1041
1051,1091
1101,1141
*NSET,NSET=LOAD1
1,101,1001,1101
*NSET,NSET=LOAD2
51,501,601,1051
*NSET,NSET=QA_TEST,GENERATE
1,41,2
*ELEMENT,TYPE=AC3D20,ELSET=EALL
1,1,3,103,101,
1001,1003,1103,1101,
2,53,102,51,
1002,1053,1102,1051,
501,503,603,601
*ELGEN,ELSET=EALL
1,20,2,1
*ELSET,ELSET=NONREF
20,
*surface,NAME=NRS
NONREF,S4
*SOLID SECTION,MATERIAL=ABSORB,ELSET=EALL
**
*MATERIAL,NAME=ABSORB
*DENSITY
 1.21,
*ACOUSTIC MEDIUM,BULK MODULUS
 0.1424E6,
*ACOUSTIC MEDIUM,VOLUMETRIC DRAG
1400.,
*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
100,
*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. This should be distributed in the ratio
**  (-1/12,1/3) to the (corner,midside) nodes, 
**  respectively:
*CLOAD,LOAD CASE=2, AMP=OMEGA
LOAD1, 8, -.33333
LOAD2, 8, 1.33333
*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
100,
*SIMPEDANCE
 NRS,
*CLOAD,LOAD CASE=2, AMP=OMEGA
LOAD1, 8, -.33333
LOAD2, 8, 1.33333
*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,EIGENSOLVER=AMS
4,,2000.,10.0,4.0,3.0
*OUTPUT,FIELD,FREQUENCY=0
*NODE PRINT,F=0
*EL PRINT,F=0
*OUTPUT,HISTORY,Frequency=0
*END STEP
**
**
*STEP
*STEADY STATE DYNAMIC
100,1000,20
***IMPEDANCE
** NONREF,I4
*CLOAD,LOAD CASE=2, AMP=OMEGA
LOAD1, 8, -.33333
LOAD2, 8, 1.33333
*ENERGYPRINT
*OUTPUT,FIELD
*NODE OUTPUT
POR,
*ELEMENTOUTPUT
ENER,ELEN,ELEDEN
*OUTPUT,HISTORY
*ENERGYOUTPUT
ALLQB,ALLWK,ALLVD,ALLSE,ALLKE
*END STEP
**
*STEP
*STEADY STATE DYNAMIC
100,
***SIMPEDANCE
**NRS, 
*CLOAD,LOAD CASE=2, AMP=OMEGA
LOAD1, 8, -.33333
LOAD2, 8, 1.33333
*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