[mickey hirata]

I try to examine monopole radiation with x=0 plane sound-hard boundary condition.
But I have trouble by above message.
please give me suggestion to solve this problem.

I executed program below in ANSYS14.5.

/title,Radiation from a monopole
/nopr
/prep7

! define material properties
rho=1.2041 ! mass density
soundv=343.26 ! sound speed
freq=1.e3 ! working frequency
wavel=soundv/freq ! wavelength
pi=3.1415926535
omega=2.*pi*freq ! angular frequency
p0=0.5*freq ! amplitude of pressure
*dim,a,array,4
a(1)=0
a(2)=a(1)+1*wavel
a(3)=a(2)+1*wavel
a(4)=a(3)+1*wavel
h=(a(2)-a(1))/6
nz1=(a(3)-a(1))/h
sourcepoint=2/3*h ! source point of x


! set model dimensions
*do,j,1,3
sphere,a(j),a(j+1),0,90
*enddo
local,12
wpcsys,,12
vsbw,all
vsel,s,volu,,4,4
vsel,a,volu,,6,6
vsel,a,volu,,8,8
vdel,all
vsel,all
vglu,all

! define elements and material
local,11 ! set up local coordinate system
wpcsys,,11
et,11,200,7 ! temporary element
et,1,30,0,1 ! normal element
et,2,30,0,1,,1 ! PML element
mp,dens,1,rho
mp,sonc,1,soundv

! assign e and m
vsel,s,volu,,5,5 ! interior
vsel,a,volu,,1,1 ! interior
vatt,1,,1,11 ! normal element region
vmesh,all
vsel,s,volu,,2,2 ! exterior
vatt,1,,2,11 ! pml element region
vmesh,all

nummrg,kp ! merge nodes
etdel,11
alls

! constrains on PML exterior surface

asel,s,ext
asel,u,loc,x,0
asel,u,loc,y,0
asel,u,loc,z,0
nsla,s,1
d,all,pres,0.


! constrains on x=0 symmetric plane
nsel,s,loc,x,0
d,all,pres,0.
alls


! analytic incident dipole inside of model
awave,1,MONO,pres,int,p0,0,sourcepoint,0,0,rho,sou ndv
finish

! perform a solution
/solu
antype,harmic ! harmonic analysis
harfrq,freq ! frequency for analysis
hfscat,total ! scattered formulation
!ascres,total ! output total pressure field
solve
finish