*HEADING
EC36AFE4: EIGENVALUE ANALYSIS, ACOUSTIC ORGAN PIPE MODES  [AC3D6]
*NODE,nset=base
1,0.,0.,0.
101,1.,0.,0.
201,1.,0.,-1.
*Ncopy,old set=base,new set=top,change number=20,shift
0,165.8,0.

*NGEN, Nset=ODB_NSET
1,21
101,121
201,221
*Nset,nset=top
21,121,221
*ELEMENT,TYPE=AC3D6,ELSET=EALL
1,1,101,201,2,102,202
*ELGEN,ELSET=EALL
1,20
*MATERIAL,NAME=AIR
*DENSITY
1.293, 
*ACOUSTIC MEDIUM,BULK MODULUS
1.42176E5, 
*SOLID SECTION,MATERIAL=AIR,ELSET=EALL
**
** Sets added by addodb
**
*Elset,Elset=ODB_ESET
EALL,
**
**
*Nset, Nset=ODB_NSET
base, 20, ODB_NSET, top
**
**
*STEP
 OPEN/OPEN CONDITION
*FREQUENCY,EIGENSOLVER=AMS
14,,2000.,10.0,4.0,3.0
*OUTPUT,FIELD,FREQUENCY=0
*BOUNDARY
base,8
top,8
*NODE PRINT
POR,PPOR
*OUTPUT,HISTORY,freq=0
*MODAL OUTPUT,VARIABLE=ALL
*END STEP
*************************
*STEP
 OPEN/CLOSED CONDITION
*FREQUENCY,EIGENSOLVER=AMS
14,,2000.,10.0,4.0,3.0
*OUTPUT,FIELD,FREQUENCY=0
*BOUNDARY
base,8
*NODE PRINT
POR,PPOR
*OUTPUT,HISTORY,freq=0
*MODAL OUTPUT,VARIABLE=ALL
*END STEP