دانلود رایگان مقاله حالت ردیابی پرتو گاوسی

Abstract

A mode parabolic equation in the ray centered coordinates for 3D underwater sound propagation is developed. The Gaussian beam tracing in this case is constructed. The test calculations are carried out for the ASA wedge benchmark and proved an excellent agreement with the source images method in the case of cross-slope propagation. But in the cases of wave propagation at some angles to the cross-slope direction an account of mode interaction becomes necessary.

6. Conclusions

The results of test calculations show that at small angles of the sound propagation track to the cross-wedge direction the acoustic field in the water is determined by the water modes only, without interaction between them, even in the case of the resonant depths. With the increase of the angle of the track to the cross-wedge direction the necessity to take into account the interaction between modes also increases, including the bottom modes. As it is stated in the paper [8] concerning the speed of calculations by the modern 3D parabolic equation method: ‘‘In a MATLAB R2011a double precision programming environment, using one central-processing-unit core on an Intel⃝R Xeon⃝R X5492 Quad-core Processor, the Pade ADI method can complete one marching step in 54 s’’. It means that in the case of our ASA wedge cross-slope track with the length of 25 km the total number of marching steps is 2500. So the time of calculation should be around 37.5 h. Meanwhile, the time of calculations by the method developed in the current paper, with the use of the alike processor (mentioned above), consists only 32 s. Thus the developed method was proved to be very efficient in calculations of the acoustic fields. At present time we develop the method also based on the ray mode parabolic equations, but including the mode interaction. We hope that this method will be applicable to the case of an arbitrary environment.