*HEADING
EC24AFAW: Nonreflective end-condition with large drag with AC2D4
Compare IMPEDANCE WITH SIMPEDANCE, and STEADY STATE DYNAMICS, DIRECT
with SUBSPACE PROJECTION.
********************
*RESTART,WRITE
********************
**
**   Mesh Generation
**
*NODE, Nset=ODB_NSET
1,    0
41,  .5
101,  0, 1.25e-2
141, .5, 1.25e-2
*NGEN,NSET=NALL
1,41
101,141
*NSET,NSET=LOAD
1,101
*NSET,NSET=QA_TEST,GENERATE
1,41
*ELEMENT,TYPE=AC2D3,ELSET=EALL
1,1,3,103
2,1,103,101
*ELGEN,ELSET=EALL
1,20,2,2
2,20,2,2
*ELSET,ELSET=NONREF
39, 
*surface,NAME=NRS
NONREF,S2
**
**  Acoustic Element Properties
**
*SOLID SECTION,MATERIAL=ABSORB,ELSET=EALL
1., 
*MATERIAL,NAME=ABSORB
*DENSITY
 1.21,
*ACOUSTIC MEDIUM,BULK MODULUS
 0.1424E6,
*ACOUSTIC MEDIUM,VOLUMETRIC DRAG
1400.,
**  
**  For reference, these IMPEDANCE PROPERTY
**  constants could be used to specify the nonreflecting 
**  condition at the given frequency:
**    1/k1=1.3541796E-06, 1/c1=1.43027502E-03
**
*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
**
************************************************  
*Elset,Elset=ODB_ESET
EALL,
*Nset, Nset=ODB_NSET
ODB_NSET, NALL, LOAD, QA_TEST
**************************************************
*STEP
*STEADY STATE DYNAMIC,DIRECT
100,
*IMPEDANCE
NONREF,I2
**
** Conditions at x=0 : Define the source inward accel
** to be  a =  omega i, so v (inward) = 1.
** Area of face=1.25e-2. (Each loaded node has a tributary 
** area of 6.25e-3) Total inward VOLUME acceleration 
** is 1.25e-2*a. Half of this is distributed to each node
** on the face:
*CLOAD,LOAD CASE=2, AMP=OMEGA
LOAD, 8, 6.25e-3
*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
LOAD, 8, 6.25e-3
*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
*FREQUENCY,NORM=MASS,EIGENSOLVER=LANCZOS
22, , ,
*NODE PRINT,F=0
*EL PRINT,F=0
*OUTPUT,FIELD,Frequency=0
*END STEP
**
**
*STEP
*STEADY STATE DYNAMIC,SUBSPACE PROJECTION
100,1000,20
*IMPEDANCE
NONREF,I2
*CLOAD,LOAD CASE=2, AMP=OMEGA
LOAD, 8, 6.25e-3
*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
100,
*SIMPEDANCE
NRS, 
*CLOAD,LOAD CASE=2, AMP=OMEGA
LOAD, 8, 6.25e-3
*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