464
J.L. Aroyan et al.
computed over each of the roughly 2 x 10
5
square subelements of the
six faces of the large rectangular extrapolation boxes used in the forward
simulations.
Although polar plots of emission data are dramatic, they do not permit
rapid examination of the pattern over all spherical angles. For this reason,
two alternate ways of visualizing the emission data are utilized in this
chapter. These alternate representations make use of the global mapping
of emission directions explained in Figure 1O.Al.
To familiarize readers with the output of the extrapolation process,
Figure 1O.A2a illustrates the far-field intensity pattern computed for a 2sided square pressure aperture (unbaffted and unphased) of side-length
2.0 A lying in the x = 0 plane. The surface pressure and normal derivative
data over a small 20 x 40 x 40 enclosing box was generated by FD simulation and then input to an extrapolation program. The normalized square
magnitude of the far-field pressure computed for 7,200 directions (3° increments in both latitude and longitude) was plotted in spherical polar
projection to create the figure. The forward and backward emission lobes
produced by this type of aperture are the main features of Figure lO.A2a.
A perspective global mapping of this same emission data with height indicating intensity is illustrated in Figure 1O.A2b, while Figure lO.A2c is a
contour plot of the same data projected down into the plane of the global
map. Once understood, these alternative representations provide an excellent means for rapid examination of the far-field data over all angles of
emission.
References
Aburto A, Rountry DJ, Danzer JL (1977) Behavioral Response of Blue Whales to
Active Sinals. San Diego, CA: Naval Command, Control and Ocean Surveillance
Center, RDT&E Division, San Diego. Technical Report 1746.
Albers VM (1965) Underwater Acoustic Handbook II. University Park, PA: The
Pennsylvania State University Press.
Alling A, Dorsey EM, Gordan JCD (1991) Blue whales (Balaenoptera musculus)
off the northeast coast of Sri Lanka: distribution, feeding and individual identification. In: Leatherwood S, Donovan GP (eds) Nairobi: United Nations Mar.
Mammal. Tech. Rep. 3, Cetaceans and Cetacean Research in the Indian Ocean
Sanctuary, pp. 248-258.
Alling A, Payne R (1988) Song of the Indian Ocean Blue Whale, Balaenoptera musculus spp., Unpublished manuscript.
Aroyan JL (1990) Numerical simulation of dolphin echolocation beam formation.
M.S. Thesis, University of California, Santa Cruz, CA.
Aroyan JL (1996) Three-dimensional numerical simulation of biosonar signal emission and reception in the common dolphin. Ph.D. Dissertation, University of
California, Santa Cruz, CA.
Aroyan JL, Cranford TW, Kent J, Norris KS (1992) Computer modeling of acoustic
beam formation in Delphinus de/phis. J Acoust Soc Am 92:2539-2545.
J.L. Aroyan et al.
computed over each of the roughly 2 x 10
5
square subelements of the
six faces of the large rectangular extrapolation boxes used in the forward
simulations.
Although polar plots of emission data are dramatic, they do not permit
rapid examination of the pattern over all spherical angles. For this reason,
two alternate ways of visualizing the emission data are utilized in this
chapter. These alternate representations make use of the global mapping
of emission directions explained in Figure 1O.Al.
To familiarize readers with the output of the extrapolation process,
Figure 1O.A2a illustrates the far-field intensity pattern computed for a 2sided square pressure aperture (unbaffted and unphased) of side-length
2.0 A lying in the x = 0 plane. The surface pressure and normal derivative
data over a small 20 x 40 x 40 enclosing box was generated by FD simulation and then input to an extrapolation program. The normalized square
magnitude of the far-field pressure computed for 7,200 directions (3° increments in both latitude and longitude) was plotted in spherical polar
projection to create the figure. The forward and backward emission lobes
produced by this type of aperture are the main features of Figure lO.A2a.
A perspective global mapping of this same emission data with height indicating intensity is illustrated in Figure 1O.A2b, while Figure lO.A2c is a
contour plot of the same data projected down into the plane of the global
map. Once understood, these alternative representations provide an excellent means for rapid examination of the far-field data over all angles of
emission.
References
Aburto A, Rountry DJ, Danzer JL (1977) Behavioral Response of Blue Whales to
Active Sinals. San Diego, CA: Naval Command, Control and Ocean Surveillance
Center, RDT&E Division, San Diego. Technical Report 1746.
Albers VM (1965) Underwater Acoustic Handbook II. University Park, PA: The
Pennsylvania State University Press.
Alling A, Dorsey EM, Gordan JCD (1991) Blue whales (Balaenoptera musculus)
off the northeast coast of Sri Lanka: distribution, feeding and individual identification. In: Leatherwood S, Donovan GP (eds) Nairobi: United Nations Mar.
Mammal. Tech. Rep. 3, Cetaceans and Cetacean Research in the Indian Ocean
Sanctuary, pp. 248-258.
Alling A, Payne R (1988) Song of the Indian Ocean Blue Whale, Balaenoptera musculus spp., Unpublished manuscript.
Aroyan JL (1990) Numerical simulation of dolphin echolocation beam formation.
M.S. Thesis, University of California, Santa Cruz, CA.
Aroyan JL (1996) Three-dimensional numerical simulation of biosonar signal emission and reception in the common dolphin. Ph.D. Dissertation, University of
California, Santa Cruz, CA.
Aroyan JL, Cranford TW, Kent J, Norris KS (1992) Computer modeling of acoustic
beam formation in Delphinus de/phis. J Acoust Soc Am 92:2539-2545.