gree of accuracy in predicting complex changes in 

 coastal conditions worldwide for tactical/opera- 

 tional use. 



Atmospheric Sciences 



The communication problem grows more com- 

 plex as communication traffic increases and diver- 

 sifies in response to new equipment and vehicles 

 put into service in the air and on the surface. The 

 ionosphere, a prime regulator of communication 

 conditions, is a dynamic and rapidly fluctuating 

 part of the earth's environment upon which most 

 Navy long-distance communications depend. Both 

 natural and manmade ionospheric disturbances 

 are of critical importance to electromagnetic wave 

 propagation. Atmospheric physics has further- 

 more been of prime interest because of its impor- 

 tance in weather forecasting. 



Accordingly, this research involves the entire 

 atmosphere affecting naval systems and opera- 

 tions, from the marine boundary layer next to the 

 ocean surface to the ionosphere, and its influence 

 on naval communications. The effort is divided 

 into these areas: The lower atmosphere and ma- 

 rine boundary layer concerned with marine fog and 

 aerosol distributions and efl"ects on optical and 

 electromagnetic transmission; midatmosphere 

 cloud physics, upper atmosphere, and strato- 

 sphere for the estimation of impact on military 

 operations and the design of high-altitude aero- 

 stats for operational uses; and ionospheric plasma 

 dynamics and solar control of the ionosphere and 

 atmosphere for improved prediction of conditions 

 afi'ecting naval communications, navigation, and 

 surveillance systems. Research is being done on 

 measurement techniques and instrumentation, par- 

 ticularly on remote sensing. 



Astronomy and Astrophysics 



Scientific investigations are made of earth-space 

 environments to determine characteristics of natu- 

 ral backgrounds, efl'ects of energetic radiations on 

 space systems and personnel, and characteristics 

 of manmade disturbances. Data and technology 

 are provided for planning and assessment of im- 

 proved systems for surveillance, communication, 

 detection, precise time determination and trans- 

 fer, missile guidance, and navigation. The re- 

 search efi'ort can be categorized into: 

 Extraterrestrial radio background limits to military 

 systems; far ultraviolet and x-ray background; 

 solar phenomena affecting the earth's ionosphere 

 and satellite environment; near earth energetic 

 particle flux of cosmic rays and effects on sensi- 

 tive systems; characteristics of manmade disturb- 

 ances; and supporting instrumentation and vehicle 

 technology. 



76 DEFENSE 



Mathematical Sciences 



Research is encouraged in many fields of math- 

 ematics and computer science related to Navy 

 missions. Current research in artificial intelligence 

 seeks to determine how computers can learn and 

 comprehend facts and relationships with the long- 

 range goal of developing humanlike capabilities of 

 adaptation and inference-making. 



Fundamental statistical research directed to- 

 ward analyzing, evaluating, and discriminating 

 stochastic signals related to radar, sonar, and oth- 

 er communications media is underway. Improved 

 system performance will be possible through the 

 development of generalized probability models, 

 better filtering algorithms, and better robust esti- 

 mation procedures. More sophisticated models are 

 needed to evaluate the environment as well as the 

 stochastic signals generated from that environ- 

 ment. 



The ONR plans to establish an acoustics insti- 

 tute in theoretical (mathematical) acoustics which 

 will be closely coupled with experimental and 

 empirical acoustics activity. Work will include 

 methods for calculating wave propagation in a 

 random medium, construction of models of ocean 

 bottom, and general numerical computational 

 techniques appropriate for acoustics problems. 

 The results will have direct application to the de- 

 sign of underwater detection and communication 

 systems and in the design of quieter ships and 

 submarines. Related research in complex com- 

 mand, control, and communications systems will 

 also have direct application to these fundamental 

 Navy missions. 



Computational Fluid Dynamics 



Computational fluid dynamics is concerned with 

 solving numerically the equations of fluid motion 

 so that useful methodology for the design and op- 

 timization of naval ships, aircraft, and weapons 

 can be developed. 



Initially, aerodynamic and hydrodynamic flows 

 were emphasized, neglecting the effects of viscos- 

 ity. Examples include the computation of super- 

 sonic flow fields about bodies, a methodology lat- 

 er utilized in both aircraft and re-entry vehicle 

 design studies. Hydrodynamic computations have 

 concentrated on air-sea interface problems, such 

 as hydrofoil performance characteristics. 

 Numerical methods for flows, including the ef- 

 fects of viscosity, are still rather primitive and are 

 restricted to highly idealized fundamental prob- 

 lems. 



Problems of transonic flows, viscous flows, un- 

 steady flows, turbulent flows, and ship wave re- 

 sistance and ship motion in a seaway will be em- 

 phasized in the future. Also included will be a 



