*HEADING
EC12AFAW: Nonreflective end-condition with large drag. AC1D2
********************
*RESTART,WRITE
********************
*NODE, Nset=ODB_NSET
1, 
41,.5
*NGEN,NSET=NALL
1,41
*NSET,NSET=QA_TEST,GENERATE
1,41
*NSET,NSET=LOAD
1,
*ELEMENT,TYPE=AC1D2,ELSET=EALL
1,1,3
*ELGEN,ELSET=EALL
1,20,2,1
*ELSET,ELSET=NONREF
20,
************************************************
**
**  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.,
************************************************
*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, QA_TEST, LOAD
**
*STEP
*FREQUENCY,NORM=MASS,EIGENSOLVER=LANCZOS, eigensolver=lanczos, SIM=NO
11, , ,-100
*NODE PRINT,F=0
*EL PRINT,F=0
*OUTPUT,FIELD,FREQ=0
*OUTPUT,HISTORY,FREQ=0
*OUTPUT,HISTORY,FREQ=0
*END STEP
**
**
*STEP
*STEADY STATE DYNAMIC,SUBSPACE
100,
*IMPEDANCE
 NONREF,I2
**
** Conditions at x=0 : Define the source inward accel
** to be  a =  omega i, so v (inward) = 1.
** Each loaded node has a tributary area of 1. 
** Total inward VOLUME acceleration is 1*a:
*CLOAD,LOAD CASE=2, AMP=OMEGA
LOAD, 8, 1.
**
*NODE PRINT, NSET=QA_TEST
COORD,POR,
*OUTPUT,FIELD 
*NODE OUTPUT,NSET=QA_TEST
POR,
*OUTPUT,HISTORY
*NODE OUTPUT,NSET=QA_TEST
POR,
*END STEP
**
*STEP
*STEADY STATE DYNAMIC,DIRECT
100,
*IMPEDANCE
 NONREF,I2
*CLOAD,LOAD CASE=2, AMP=OMEGA
LOAD, 8, 1.
**
*NODE PRINT, NSET=QA_TEST
COORD,POR,
*END STEP