A NEW PROCEDURE TO ACHIEVE REQUIRED ACCURACY IN COMPUTATIONAL OCEAN ACOUSTICS: THEORETICAL DEVELOPMENT

Ocean acoustic wave propagation can be predicted by applying numerical methods to solve representative wave equations computationally. For this purpose, numerical methods have been introduced; a latest introduction was the Predictor-Corrector Method. An important question arises: Whether or not these numerical methods can produce satisfactory required accurate results? This may cause an accuracy concerned by the users. This paper introduces a new Predict-Correct Procedure to examine whether or not the result meets the accuracy requirement. If not, the procedure can improve the result until it becomes satisfactorily accurate. Discussions will be given on the mathematical and computational developments of the Predictor-Corrector Method as well as the Predict-Correct Procedure. Following that is a discussion on how the Predict-Correct Procedure works. An important part of this paper is devoted to show how this new procedure can achieve the goal of obtaining the required accurate prediction results.

RAY CHAOS IN UNDERWATER ACOUSTICS AND ITS APPLICATION

In this note we revisit the channelling effect of deep ocean acoustic wave propagation. To model propagation phenomena ray theory is used, where particular attention is payed to ray chaos. The effect of transitions between two archetypal sound speed versus depth profiles (Munk and double duct profiles) is studied. To do this the novel concept of launching basin is introduced. Its use in identifying the launching parameters of rays which remain stable is indicated, something which is highly desirable for understanding sonar system performance.