Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Simple illustrations of range-dependence and 3-D effects by normal-mode
  sound propagation modelling   As is well known, the sound-speed profile has significant effects on
underwater acoustic sound propagation. These effects can be quantified by
normal-mode models, for example. The basic case is a laterally homogeneous
medium, for which the sound speed and the density depend on depth only and not
on horizontal position. Effects of horizontal medium-parameter variation can be
quantified by coupled-mode models, with coupling between mode expansions for
laterally homogeneous parts of the medium. In the present paper, these effects
are illustrated for media with a particularly simple horizontal parameter
variation such that mode shapes do not vary with horizontal position. The modal
wavenumbers depend on horizontal position, however. At a vertical interface
between regions with laterally homogeneous medium parameters, each mode is
reflected as well as transmitted. For the media considered, reflection and
transmission coefficients can be computed separately for each mode without mode
coupling, and this is done recursively, stepping through the laterally
homogeneous regions in appropriate order. Continuous-wave as well as pulse
computations are used to illustrate frequency-dependent reflections from ridges
and diffraction into shadow zones behind islands, for example.

37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys
7
The categories of this paper are: hep-th
32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex
21
The categories of this paper are: adap-org
1
The categories of this paper are: cs
36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
29
The categories of this paper are: funct-an
12
The categories of this paper are: nucl-th
14
The categories of this paper are: math-ph
26
The categories of this paper are: bayes-an
28
The categories of this paper are: alg-geom