Here
we present the results of benchmarking SWAMPRA.FOR against the Range-dependent
Acoustic Model (RAM) by Collins. The benchmark problem contains
range-independent bathymetry and a sound speed profile for Gulf water which
varies with depth. The sound speed profile for three types of water in Mexican
Gulf was obtained from Ocean Acoustic Library and it is shown on Fig. 1.
The
receiver depth and the source depth was 900m, test frequencies were 500 Hz and
1000 Hz.
Fig.2
and 3 show plots of the transmission loss versus range obtained with SWAMP and
RAM.
The
input file SWAMPRA.IN for frequency 500 Hz was:
1 2025.0 2025.0 900.0 900.0
500.0 ! nwhat,h, hhh, hs, hr, freq
1.0 1.8 1600.0 0.35
! rho0, rho1, c11, alpha
75
500000.0 500000.0 500000.0 !
dh(mult.r), rstart, rall, rend
500.0
100.0 500.0 .5 ! rrr1 delrm delrs
DMS accuracy par.
%
Sound speed profile: depth, sound speed %
-1 -1 ! Terminate with -1 –1
To read the
description of each parameter go here:
User manual for "SWAMP-1 CW propagation"
The
input file RAM.IN for RAM for frequency 500 Hz was:
Fig.1
range-independent
example
500.0
900.0 900.0 freq zs zr
500000.0
500.0 2 rmax dr ndr
4000.0 2.0 1 2025.0 zmax dz ndz zmplt
1500.0
8 1 0.0 c0 np ns rs
0.0
2025.0 rb zb
500000.0
2025.0
-1
–1
%
Sound speed profile: depth, sound speed %
-1
-1
0.0
1600.0 z cb
-1
-1
0.0
1.8 z rhob
-1
-1
3900.0
0.5 z attn
4000.0
20.0
-1
–1 Fig.2 Fig.3