Running the Program

The KRAKEN program is actually part of a complete package of modeling tools referred to as the Acoustics Toolbox and structured as shown in Fig. 4.1. Besides the KRAKEN normal mode model, there is also a 1) ray/beam tracing model, BELLHOP , 2) an FFP (spectral integral), SCOOTER , and 3) a time-domain FFP model, SPARC .

  
Figure: Structure of the Acoustics Toolbox.

The models take as input a user-provided environmental file (ENVFIL) to describe the problem. This file has the same format for all models. PLOTSSP can be used to produce a plot of the sound speed profile defined in the environmental file.

The models then produce a binary `shade' file (SHDFIL) that contains calculated pressure fields. PLOTFIELD can be used to convert the pressure to transmission loss and produce a color or grey shade plot of the transmission loss over range and depth. The program PLOTSLICE is used to plot a slice of the field along a fixed receiver depth. Additional programs exist for using the shade files to do matched-field processing, to compute a probability of detection or a radius of detection.

There are utilities available for converting between the NRL shade file format and the SACLANTCEN format (TONRL and TOSAC). This allows the SACLANTCEN models to be plotted using PLOTFIELD and PLOTSLICE for intermodel comparisons. There are also utilities for converting the shade file to an ASCII format (TOASC) and back to their original binary format (TOBIN). These programs allow you to transfer files between computers with incompatible binary files by transferring an ASCII file instead.

While the basic structure is as shown in Fig. 4.1, each of the models has additional plotting routines which are unique to it. For instance, the BELLHOP ray model produces rays and so it has a ray plotting program, while the KRAKEN normal mode produces modes and so it has a mode plotting program. In this chapter, we focus on the description of the KRAKEN component, however, the other models are also discussed (briefly).

Most of the development work has been done on a VAX using VMS Fortran but careful thought has been given to portability. The following changes are necessary to run KRAKEN under UNIX using the f77 compiler:

1. Change the logical record length used for opening files. VMS uses longwords (4 bytes) most other systems seem to use bytes.

2. Change the timing routines in TIME.FOR.

3. Change the machine constants in SLATECBESSEL.FOR or eliminate the Twersky ice-scatter option which uses those routines. This is done by replacing TWERSK.FOR with TWERSKYFUSE.FOR. With the latter routine it is no longer necessary to link with SLATECBESSEL and MATHIEU.

4. Apparently there is no way for the Unix system to retrieve a record length for a file automatically. You will need to modify the mode-file format to include the record length, do a preliminary read to obtain the record length, then re-open the file with the correct record length.

5. If you have core space problems, change the parameter MAXN which controls the maximum number of mesh points in depth. In KRAKEN this and other parameters are defined in the include-file COMMON.FOR . Similar include-files exist for KRAKENC , SCOOTER , SPARC , and BELLHOP .

• Structure of the KRAKEN model
• The Main Program
  • notes.hlp
  • kraken.hlp
• Acoustic Field Calculations
  • field.hlp
  • field3d.hlp
• Plotting routines
  • plotfield.hlp
  • plotgrn.hlp
  • plotmode.hlp
  • plotslice.hlp
  • plotssp.hlp
  • plottld.hlp
  • plottlr.hlp
  • plottri.hlp
• The BELLHOP ray/beam model
  • bellhop.hlp
  • plotray.hlp
• The SCOOTER FFP model
  • scooter.hlp
  • fields.hlp
• The SPARC pulse model
  • sparc.hlp
  • plotts.hlp
• The BOUNCE reflection coefficient model
  • bounce.hlp
  • plotrth.hlp