POSITIONS OF TRANSDUCER ELEMENTS IN AN ACOUSTIC 'NEAR-FIElD' ARRAY. 

 REPORT NO. NRL-6728 (MAY 1968. ^OP) BY GERAlD A. SABIN. DDC NQ. IS 

 AD-669-449. 



UNDERWATER SOUND REFERENCE DIV. 

 NAVAL RESEARCH LABORATORY 

 ORLANDO, FLORIDA 



SOUND - NORMAL MODES »-*-* 



NORMAL MODE SOLUTIONS FOR SOUND SPEED PROFILES LANGUAGE - FORTRAN IV 



COMPUTER - CDC 3800 



PROVIDES A NORMAL MODE SOLUTION OF THE WAVE EQUATION WITH THE SOUND 

 SPEED PROFILE FOR THE MEDIUM REPRESENTED BY A SET OF DISCRETE VALUES. 

 THE SEA BOTTOM IS ASSUMED TO BE A SEM I -I NF I N I T E FLUID, SPECIFIED BY A 

 CONSTANT DENSITY AND A CONSTANT SPEED OF SOUND AND WITH NO ATTENUA- 

 TION. THE INTERFACE BETWEEN THE WATER COLUMN AND THE BOTTOM IS FLAT 

 AND LEVEL. USER SELECTS THE MAXIMUM NUMBER OF MODES DESIRED. OUTPUT- 

 - THE NORMALIZED E I GENFUNCT I ONS OR MODE SHAPES ARE OBTAINED FROM THE 

 EIGENVALUES AND PLOTTED. THE GROUP VELOCITY CHARACTERISTIC IS OB- 

 TAINED OVER A RANGE OF FREQUENCIES AND TABULATED. PROPAGATION LOSS IS 

 PLOTTED AS A FUNCTION OF RANGE. DOCUMENTATION WILL BE IN A FORTH- 

 COMING NRL REPORT. 



JOHN CYBULSKI 



CODE 8177, ACOUSTICS DIVISION 

 NAVAL RESEARCH LABORATORY 

 WASHINGTON, D. C. 20390 



PROPAGATION LOSS - NORMAL MODES LANGUAGE - FORTRAN 



COMPUTER - CDC 3800 



CALCULATES UNDERWATER SOUND PROPAGATION IN A HORIZONTALLY STRATIFIED 

 MEDIUM. THE PROGRAM CALCULATES A SET OF HORIZONTAL PHASE VELOCITIES 

 FOR THE NORMAL MODES AND THEN SERIES THE MODE AMPLITUDE FUNCTIONS TO 

 FIND THE SOUND LEVELS. INPUT — SOUND VELOCITY PROFILE, SOURCE DEPTH, 

 POSITION OF RECEIVERS IN RANGE AND DEPTH, SURFACE LOSS, AND BOTTOM 

 LOSS TABLE. OUTPUT — PROPAGATION LOSS AT THE VARIOUS RECEIVERS. PRO- 

 CEDURE — APPROXIMATE VALUES OF THE HORIZONTAL PHASE VELOCITY ARE CAL- 

 CULATED USING RAY THEORY. EXACT VALUES ARE FOUND BY ITERATING IN THE 

 COMPLEX PLANE. SOUND INTENSITIES ARE CALCULATED BY FORMING THE SERIES 

 OF NORMAL AMPLITUDE FUNCTIONS. DOCUMENTATION — FORTHCOMING NRL REPORT 



DR. H. P. SUCKER, JR. 

 CODE 8170 



NAVAL RESEARCH LABORATORY 

 WASHINGTON, D. C^ 20390 



SOUND - SPEED COMPUTATIONS 



SOUND VELOCITY LANGUAGE - FORTRAN 



COMPUTER - CDC 3200 

 (COPY ON FILE AT NODC) 



COMPUTES SOUND VELOCITY USING WILSON'S EQUATIONS. OUTPUT CARDS HAVE 

 VELOCITY OF SOUND IN METERS/SEC, PRESSURE IN KG/SQ-CM, SIGMA-T, IN 

 ADDITION TO INPUT STATION DATA AND IDENTIFICATION. 



NAVAL UNDERWATER WEAPONS RESEARCH 



PAGE 100 



